# Full Throttle Hesitation



## TheRealist (Oct 28, 2009)

Ok.. *sigh* here it goes..
At full throttle ONLY i get hesitation (lets say in 2nd gear since its the most noticable)
Heres how it goes.. normal shift from 1st to 2nd @ 3000rmp
in 2nd I floor it.. now from 2500rpm to 5000rpm i get around 3 hesitations.
it doesnt jerk at all.. its just like the boost leaves me or the fuel is not being sent properly.. who knows..
Heres the tricky part.. it doesnt happen all the time....








I've been to the dealer and the problem didn't appear when i tried it with the mechanic... bottom line.. he doesnt know wtf is wrong with the car. Probably think im nuts







And oh yes, no codes..
I really would need some help here.. going to the dealer again this week..


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## groggory (Apr 21, 2003)

Hm... dirty fuel filter?
Have you checked your spark plugs (gap and clean)
Do you put good gas in? It could be dirty injectors or a bad fuel pump.


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## j.burton50 (Oct 20, 2008)

*Re: (groggory)*

sounds like a missfire. just cause theres no code doesnt mean its not there. did you actually get the codes pulled or are your going by the CEL? missfire can be from dirty injectors/spark plugs, fuel filter etc. just like ^ stated above. sounds like ur rdy for a full tune up and some fuel injector treatment 
id bet against the fuel pump being bad tho.


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## groggory (Apr 21, 2003)

The fuel pump is a long shot...but possible.


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## TheRealist (Oct 28, 2009)

*Re: (groggory)*

Plugs have been changed 10000kms ago. Didnt check them tho.
I'll try to change the fuel filter. 
Dunno about the fuel pump.. maybe i'll ask them to check the pressure when I go?
Always put 91 oct in or 94 when I can. So thats not an issue.
So maybe I should just ask to do a full clean up of the fuel lines, injectors etc? 
would some BG 44k work for me?


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## Pimpert88 (Sep 20, 2008)

having same problem bump


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## jettasmooth (Aug 7, 2002)

*Re: (Pimpert88)*

what plugs? and what gap are you running? Could be improperly gapped. If you are running BKR7E, they need replacing much more frequently.


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## TheRealist (Oct 28, 2009)

*Re: (jettasmooth)*

I dont't know what plugs.. bought the car at the dealer used and said the plugs had been changed.
what plugs should i put on it then for stock engine?


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## jettasmooth (Aug 7, 2002)

*Re: (TheRealist)*

if the plugs were done at the dealer, they should be correct (if they actually replaced them)
sounds like a bad wiring harness or coilpack on the fritz. Check your coilpack harness and see if there are any wires that are cracked.


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## TheRealist (Oct 28, 2009)

*Re: (jettasmooth)*

Keep in mind.. the problem isnt always there either... and when it does it... its like i get more boost that i usually do when its not doing it.. (during the surge/loss type boost)
it goesssssssssss stop goesssssssssssss stop goessssssssssss
all in 2nd gear..and its smooth how it does it.. doesnt cut off violently.
wires are fine.. checked them yesterday..
If someone can find this prob ill be the happiest dude


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## groggory (Apr 21, 2003)

*Re: (TheRealist)*


_Quote, originally posted by *TheRealist* »_Keep in mind.. the problem isnt always there either... and when it does it... its like i get more boost that i usually do when its not doing it.. (during the surge/loss type boost)
it goesssssssssss stop goesssssssssssss stop goessssssssssss
all in 2nd gear..and its smooth how it does it.. doesnt cut off violently.
wires are fine.. checked them yesterday..
If someone can find this prob ill be the happiest dude









How did you check the harness? Did you pull back any of the friction tape and look?
Honestly, I'd start with a pressure test.
Vacuum leaks are a b1tch for turbo charged cars...just sooo many systems depend on a clean vacuum system.


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## TheRealist (Oct 28, 2009)

*Re: (groggory)*

ahh thats what i didnt want to hear..
so what do I tell the dude at the dealer.. do a boost leak?
such trouble for this problem.. sheeshh
Dealer hasnt found squat last time i went for that problem..


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## groggory (Apr 21, 2003)

Do a pressure test.
Pressure test the entire intake and vacuum system.


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## TheRealist (Oct 28, 2009)

AT 10 psi is that enough for stock engine?


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## bass_4_ever (Dec 6, 2007)

this happened to me... i changed the coilpacks, spark plugs, gaps, maf, etc. I was told to change the 02 sensors (front & rear) as well as the *TEMPERATURE SENSOR*. My car no longer misfires. I checked it out with a vag-com, aparently my temperature gauge was reading 90 degrees inside the car. With a vag-com, the temperature was reading @ 78-85 degrees and not warming up anymore. Turns out my temperature sensor was reading the engine was cold and needing to warm up. So it was feeding more gas than needed into the engine to compensate for the cold engine. After changing my 02 sensors & temperature sensor (not thermostat) the car runs like a champ! Good luck!


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## TheRealist (Oct 28, 2009)

Thanks for the reply Bass, i'll take everything in account and see what I can change without breaking the bank. My car is under warranty but they wont change squat since there is no CEL... these *******  

Thanks to everyone for helping out.. I'll post some updates when i changed some things.


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## TheRealist (Oct 28, 2009)

Alright I got some updates. 

I changed my spark plugs yesterday, and one of them (plug #3) had some oil on the thread... now could this be the misfiring or hesitation at full throttle I was looking for? 

Any inputs? I mean it shouldn't be tough to change the valve cover.. but just wanted to know if that could be the slight hesitation i am getting...


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## TheRealist (Oct 28, 2009)

Ok guys, it was the cover gasket for the leak and finally got codes P0330 and P0300 (misfires) so change the coil on that cylinder. 

Thanks for your help peeps


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## bass_4_ever (Dec 6, 2007)

thanks for the update!


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## TheRealist (Oct 28, 2009)

Ok new updates!!!
not good ones tho..
The slight hesitation at full Throttle is still there.. but its like the probleme is not as noticeable...

Bringing in the car again for a diagnostic..


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## thelettert (Sep 23, 2005)

if u changed out ur coils then Im practically positive its your MAF starting to die. Just had the same problem myself. You should try cleaning it in 99% alchohol solution first. 

Mine started doing all that ****tyness and finally the traction and engine light came on simultaneously. (which usually means the MAF is officially dead... or that a wheel speed sensor died) but anyway, Checked the readings with a scanner.. had zeros accros the board. Bought a brand new bosch one from ecs for like a hundred bux, popped it in, problems gone. car pulls like a champ now. (besides that im overheating stil lol)


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## DexYves (Jun 30, 2009)

bass_4_ever said:


> this happened to me... i changed the coilpacks, spark plugs, gaps, maf, etc. I was told to change the 02 sensors (front & rear) as well as the *TEMPERATURE SENSOR*. My car no longer misfires. I checked it out with a vag-com, aparently my temperature gauge was reading 90 degrees inside the car. With a vag-com, the temperature was reading @ 78-85 degrees and not warming up anymore. Turns out my temperature sensor was reading the engine was cold and needing to warm up. So it was feeding more gas than needed into the engine to compensate for the cold engine. After changing my 02 sensors & temperature sensor (not thermostat) the car runs like a champ! Good luck!


Is the "*TEMPERATURE SENSOR*" you're talking about the "air temp sensor" or "water temp sensor"?


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## jpelcman (Feb 7, 2010)

i believe that could be the coolant temp sensor, anyways is it possible this is a dv issue or possibly an n75? im having similar issues


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## DexYves (Jun 30, 2009)

I also have similar problems. I have new coil packs, new fuel filter, fuel line cleaned, sea-foamed. And my car kept throwing MAP sensor codes. So I'm guessing the sensor is either bad or covered by too much oil. I'm gonna upgrade my IC and check or replace the MAP sensor. I'll let you know if that solves the problem.


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## TheRealist (Oct 28, 2009)

DexYves said:


> I also have similar problems. I have new coil packs, new fuel filter, fuel line cleaned, sea-foamed. And my car kept throwing MAP sensor codes. So I'm guessing the sensor is either bad or covered by too much oil. I'm gonna upgrade my IC and check or replace the MAP sensor. I'll let you know if that solves the problem.


I just cleaned my fuel lines too, injectors, etc.. much better now.. dunno if the problem is going to pop up again.. haven't drove my car enough since..

I'll let you know about it.. please post anything that solved something


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## kay207 (Nov 20, 2009)

*Same issue!*

You know... I have been dealing with this same problem since I have gotten my 2001 1.8t Jetta in July of 2009 , and no matter how many posts I have read about the same problems, not 1 has ever turned up a definite solution to the problem! I have changed *my spark plugs, coil packs, DV, MAF, CTS, First O2 sensor, vacuum pump, alternator, thermostat (twice), the timing belt and the water pump*... and get this, I am still getting a CEL and sometimes have a strange hesitation in boost... Any recommendations? At some point I am going to do a pressure test ( having the time to do it evades me though). I am thinking about getting some new spark plugs in the meantime, I have a stock AWW engine... what should I get?


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## DexYves (Jun 30, 2009)

kay207 said:


> You know... I have been dealing with this same problem since I have gotten my 2001 1.8t Jetta in July of 2009 , and no matter how many posts I have read about the same problems, not 1 has ever turned up a definite solution to the problem! I have changed *my spark plugs, coil packs, DV, MAF, CTS, First O2 sensor, vacuum pump, alternator, thermostat (twice), the timing belt and the water pump*... and get this, I am still getting a CEL and sometimes have a strange hesitation in boost... Any recommendations? At some point I am going to do a pressure test ( having the time to do it evades me though). I am thinking about getting some new spark plugs in the meantime, I have a stock AWW engine... what should I get?


What's the code coming out with the CEL? Mine was usually about the MAP sensor.


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## bassep (Apr 11, 2010)

TheRealist said:


> Always put 91 oct in or 94 when I can. So thats not an issue.
> So maybe I should just ask to do a full clean up of the fuel lines, injectors etc?
> would some BG 44k work for me?


Just because you're using a good octane doesn't mean the quality of the gas is good. I started using gas at a new station down the road - a kangaroo gas station which didn't specify a name brand. I always use 93 Oct. It took a few months and a couple of bottles of techron cleaner before I linked the gas station up to my car running really sh***y. Unfortunately I'd also put a new set of plugs on in between :banghead: I just went back to the old station across the road and paid the extra couple of cents per gal. for Chevron with techron additive and that's all I use ever since. No more problem. I don't know about the BG stuff but I will swear by the techron injector cleaner.


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## kay207 (Nov 20, 2009)

DexYves said:


> What's the code coming out with the CEL? Mine was usually about the MAP sensor.


The code is a P1296... which is a cooling system malfunction code... I have done just about everything to the cooling system and the light still hasn't turned off... the water pump was just changed on monday.


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## TheRealist (Oct 28, 2009)

Alright so the dealer didnt find anything wrong (what a surprise) saying it pulled fine... No codes he said too.

He updated the ECU after he cleaned my whole fuel lines (injectors..)

So i noticed today after driving hard that the problem appeared again..:banghead: but it was less frequent or less noticeable if I can say. 

I also notice that it ALWAYS and I say ALWAYS ONLY happens when i floor it at low RPM.
if im running at 4000 rpm and floor it while being in 2nd gear, its all good. ONLY happens when i floor it from 2000 rpm and that is in every gear..and doesn't happen 100% of the time.

I can hear the turbo spooling.. and the suddenly it reduces spool speed for .5 sec goes back to normal and the does it again... so its like a valve or something is saying.. "ok too much air stop spooling for .5 sec" the starts back..

But i mean.. why would it ONLY do it while the spool starts from 1800-2000 rpm.....mystery:screwy:


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## slayer001 (Apr 26, 2010)

*turbo stops spooling ??? OMG*

That is called Turbo surging. ECu is requesting too high boost, when exhaust gases do not have enougth power to spin it.
So the turbo stops .....

Troubleshooting:
a) bad DV, or just broken vacuum line to DV.
test DV, disconnect vacuum line, which goes to DV and test if there is vacuum, when engine running on iddle. Remove DV and try it it is sealed - no air shall flow. Apply vacuum on DV and air shall flow freely.
b) bad map in ECU closing N75 valve too much, which leads to turbo stalling
)
c) bad N75, remains closed 
d) vacuum leak in pipe bringing pressure from turbo outlet to N75 or vacuum leak from N75 to Wastegate valve.
Disconnect electrical connector on N75 valve and test the car. 
If there is no hesitation = good pipes, still may be bad N75 or Ecu
hesitations remains =repair leak in tubes
e) may be bad wastegate - internal spring is too strong, or WG is slighty blocked

*
In any case, Turbo surging = stopping is damaging the turbo, so be very careful*


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## TheRealist (Oct 28, 2009)

kay207 said:


> I am thinking about getting some new spark plugs in the meantime, I have a stock AWW engine... what should I get?



get those : PFR6Q from NGK


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## TheRealist (Oct 28, 2009)

*nice*



slayer001 said:


> That is called Turbo surging. ECu is requesting too high boost, when exhaust gases do not have enougth power to spin it.
> So the turbo stops .....
> 
> Troubleshooting:
> ...


Thx for that reply, very helpful. I will check everything you mentionned tommorow and let you all know what might be wrong.
But yeah it is the turbo that stops, like the spooling hesitates for 1 second..

Btw, what do you mean by "Remove DV and try it it is sealed " missed that one.. hehe can u detail it more since im clearly a DV newb.

Thanks dude


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## calvin_xl (Feb 21, 2007)

*vagcom graph*

My symptoms looks the same as yours, but start at 2500+ rpm.
I changed the DV, boost surge is still there.
Bellow are 2 runs with the vagcom graph. The gray line is the N75 duty cycle. The funny thing is that it works well for a wile and then goes back to 0 in the middle of the acceleration several times.
Can a faulty N75 could have this funny behavior ? I was expecting something like if faulty = does not work at all, but not times to time. 

The first run is with a cold engine (and N75 behavior is normal), second run is with hot engine (N75 crapy behavior).


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## TheRealist (Oct 28, 2009)

calvin_xl said:


> My symptoms looks the same as yours, but start at 2500+ rpm.
> I changed the DV, boost surge is still there.
> Bellow are 2 runs with the vagcom graph. The gray line is the N75 duty cycle. The funny thing is that it works well for a wile and then goes back to 0 in the middle of the acceleration several times.
> Can a faulty N75 could have this funny behavior ? I was expecting something like if faulty = does not work at all, but not times to time.
> ...


Well it sure looks like my issue... its like in the same hard acceleration I have several drops that are equally spaced throughout the run...although my issue is there also when engine is cold..:laugh:

Let me know what you find.. i am about to change DV and N75.. but not sure its really that.. This thing has been going on forever and no codes, plus dealer not finding anything.. guess i'Ll have to start changing random things :sly: hehehe...

anyways, for the benefit of all, please post any improvement of any sort that could help.


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## calvin_xl (Feb 21, 2007)

*new n75 ordered*

I sure will quick the results posted.
I have ordered a new n75 that should arrive in a week.
For information I also tried the test with the n75 connector unplugged as slayer001 suggested.
The results was that there were no more hesitations, so that should clear an eventual leak issue.
Of course, try this test carefully (do not run 20 miles with full throttle or bye bye turbo), one acceleration is enough.


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## GLI_1.8T (Jul 21, 2004)

calvin_xl said:


> I sure will quick the results posted.
> I have ordered a new n75 that should arrive in a week.
> For information I also tried the test with the n75 connector unplugged as slayer001 suggested.
> The results was that there were no more hesitations, so that should clear an eventual leak issue.
> Of course, try this test carefully (do not run 20 miles with full throttle or bye bye turbo), one acceleration is enough.


Doesn't the N75 stay open when it is unplugged? Therefore it will only hold whatever the wastegate spring is capable of doing, around 5psi?


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## vwturbo02 (Sep 8, 2006)

Yeah, i thought N75 made the car go into limp mode? :sly:


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## Atomic Ed (Mar 19, 2009)

Humm.... It could be something as simple as timing pull-back due to the knock sensors. If you have Vag Com, log group 20 and 115. If the timing pull is more than 5-6 degress, and it's at the same rpm in the dip in the actual boost, then you may have a lean condition or too much timing advance at temp.


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## TheRealist (Oct 28, 2009)

Atomic Ed said:


> Humm.... It could be something as simple as timing pull-back due to the knock sensors. If you have Vag Com, log group 20 and 115. If the timing pull is more than 5-6 degress, and it's at the same rpm in the dip in the actual boost, then you may have a lean condition or too much timing advance at temp.


hmm.. if no Vag-Com then im screwed for that check up ...

but explain time pull.. My timing belt was changed i'd say 6 months ago.. if it was a tooth off it would show a CEL for sure..
so what is timing pull-back exactly?


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## chucklesmcfarland (Apr 6, 2008)

Hey folks,

I'm gonna start following this thread since I am having a similar issue. I can see it's driving others crazy too.

:banghead:


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## calvin_xl (Feb 21, 2007)

*timing advance ?*

Hi Atomic, thanks for the proposal.

I will check that as soon as I go home.
A question, I assume that on our car the timing advance is manage by the ECU, so how can I eventually modify it, is it something I can program?

Thanks,


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## Atomic Ed (Mar 19, 2009)

Sorry,

Timing pull is just my slang for retarding the timing. If you are getting timing retard, it's a result of your problem, not the cause. You can adjust timing with a free software tool called Lemmiwicks (do a search), but you need to figure out what's going on first.

Are using a stock turbo and stock ECM software (not chipped?)? If so, and you are getting timing pull, then engine knock is coming from some source. Either a lean condition, like dirty injectors, bad FPR or other things that are limiting fuel flow. Too high of an engine temp or air inlet temp will also cause timing retard. 

If you find out you have timing retard, take the info back to your mechanic and let him do some further diagnostics.


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## TheRealist (Oct 28, 2009)

Atomic Ed said:


> Sorry,
> 
> Timing pull is just my slang for retarding the timing. If you are getting timing retard, it's a result of your problem, not the cause. You can adjust timing with a free software tool called Lemmiwicks (do a search), but you need to figure out what's going on first.
> 
> ...


Thx for the explanation. As for me, my 1.8t is bone stock. Just got the injectors cleaned (fuel line etc), replaced plugs, replaced one bad coil.
Brought it to the dealer several times, no codes except for that 1 time where there was a misfire and then he changed the bad coil. Oil on one plug so he also changed the valve cover gasket.

So i am now with an issue that could come from different things (MAF, N75, DV, Boost leak, etc)
still waiting on that N75 update  I'll see if I need to change mine after that..


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## jettasmooth (Aug 7, 2002)

you could just unhook the N75 vac lines and block it off, and run it on wastegate boost pressure to see if your hesitation disappears.

Also if you have a bad MAF, simply unplugging it should make the car run better, since it will default the MAF and use the 02 and MAP for fueling adjustment instead.


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## DubDubin90 (Apr 9, 2008)

Try unplugging your MAF and drive around. The car will probly run like crap and have a little less power but if the stuttering stops then you'll know if its the MAF. Just a free way to check that...I would also keep looking into the N75 and vac lines for issues. For the DV, he meant earlier to pull out the DV valve, push the valve all the way up through the bottom n put your finger over the nipple on top to seal it n see if the valve stays open when your finger prevents air from entering the top through the nipple. Check by blowing through it. Then make sure you cant blow through it when it's in its normal position. Other then that just check little vac stuff n do a boost test. look it up how to do it. GL!


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## DubDubin90 (Apr 9, 2008)

Didn't mean to repeat jettasmooth's post about MAF just saw it lol


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## Dub-Nub (Sep 27, 2005)

My buddies car is having the same problem, he brought it over to my house today to check it out

Did a boost leak test, found a problem by the AFR hose, tightened it up. No more leaks were heard. 

His mechanic switched the o2 sensors around, the front was in back and back was in front which we changed

His coilpack wiring harness has cracks in it and i am thinking that is causing the problem

I suggested for him to switch to copper plugs, he is getting coilpacks switched out 31st. Right now he is driving without the MAF plugged in and will update me, he said its his 2rd MAF. What would cause MAF's to go bad this fast?


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## TheRealist (Oct 28, 2009)

Dub-Nub said:


> Right now he is driving without the MAF plugged in and will update me, he said its his 2rd MAF. What would cause MAF's to go bad this fast?


I'd say from oil from filter, if he is in fact using K&G air filters...:thumbup:

He seems to have a much bigger problem that i have... Drove the car today, ran it hard.. and its not doing the hesitation...:screwy: this thing comes up whenever it feels like it..:banghead:


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## Dub-Nub (Sep 27, 2005)

He is using a Neuspeed filter that does require oiling, i told him he is probably over oiling the thing.

I am hoping the fact that the o2 sensors were backwards busted the MAF sensor somehow, not sure how but maybe it had to work harder or something gosh i dont know lol but the only code that came up was for o2 sensor.

He let me know that with it unplugged it was driving fine and with the maf plugged in it was causing problems where it felt like tiny misfires and would not boost well.


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## vee_dubb_gti (Nov 17, 2004)

*Ding ding ding!*



Atomic Ed said:


> Humm.... It could be something as simple as timing pull-back due to the knock sensors. If you have Vag Com, log group 20 and 115. If the timing pull is more than 5-6 degress, and it's at the same rpm in the dip in the actual boost, then you may have a lean condition or too much timing advance at temp.


2X :thumbup:

need to log timing pull and intake air temps.


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## DubDubin90 (Apr 9, 2008)

Dub-Nub, I've heard that having a short ram intake will mess MAFs up, probably cause of the oil like you said. I wouldn't oil it at all anymore and try cleaning up the old MAFs. You can look up how to do it using 99% alcohol or something


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## TheRealist (Oct 28, 2009)

vee_dubb_gti said:


> 2X :thumbup:
> 
> need to log timing pull and intake air temps.



hmmm.. for my problem i doubt it.. the IAT that is. I don't have an increased crank time when engine is cold nor do I have poor fuel economy nor do i have spark knock.


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## Dub-Nub (Sep 27, 2005)

DubDubin90 said:


> Dub-Nub, I've heard that having a short ram intake will mess MAFs up, probably cause of the oil like you said. I wouldn't oil it at all anymore and try cleaning up the old MAFs. You can look up how to do it using 99% alcohol or something


We are going to wait for the new coilpacks and new spark plugs to see how that affects it, it probably will not change anything but its an extra thing to cross off the list and wouldnt hurt. After that we will do a MAF cleaning using some specific MAF cleaner and after that take care of the coilpack harness cracks..i am thinking just some electrical tape and then cover it up using some heat shield or something.


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## kay207 (Nov 20, 2009)

*N75 location*

Where exactly is the N75 located? It is something that I would like to look into changing next... seeming as how I have changed just about everything else in the last 8 months. lol:banghead:


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## Dub-Nub (Sep 27, 2005)

kay207 said:


> Where exactly is the N75 located? It is something that I would like to look into changing next... seeming as how I have changed just about everything else in the last 8 months. lol:banghead:


IN this picture is the device thats top left of the brake fluid cap (yellow), has 2 hoses going into it and it sits inside the TIP.


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## Dub-Nub (Sep 27, 2005)

My buddies car has been fixed as he states. The problem was the front and rear o2 sensors were switched, after the car adapted the problem disappeared.


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## Chodaboy1.8t (Jan 24, 2005)

*Any updates?*

Just wanted to see if there have been any solutions to the problem, having the same issues myself...


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## As4urazz (Mar 25, 2006)

Take a look at ur PVC hoses under intake manifold. Follow the y pipe from cylinder head down under intake. Remove the bracket betw intake and radiator to get a good look.


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## TheRealist (Oct 28, 2009)

Chodaboy1.8t said:


> Just wanted to see if there have been any solutions to the problem, having the same issues myself...


Well i'm still waiting on Calvin to shoot me his results after he changed the N75 valve.

I'll let ya know if anything does it for me.. right now nothing has fixed it from what I did.. I doubt its a boost leak since i get a good boost most of the time. Anyways, i'll keep posting.


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## rustywoodstone (Jul 6, 2007)

I had a problem like the one you guys are figuring out now. I replaced the hockey puck thing in this picture. The thing under the word remove. I also added a newer N75 (stock) and lastly upgrade my smic. 

My hesitation went away.

Figured I would add that for what it's worth. Good luck!


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## groggory (Apr 21, 2003)

The hockey puck thing (PCV Valve) would be a good thing to check. It should act as a one-way valve (engine -> intake). If you can blow (intake -> engine) that is bad. Basically your metered air from your MAF will now be allowed to flow into the crank case and valve cover which means the ECU's calculations will be messed up.

Check it out. It'd be nice if that were the problem.


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## TheRealist (Oct 28, 2009)

sweet, its easy to check too. Ill check it out when I get home. let you know soon.


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## rustywoodstone (Jul 6, 2007)

yeah and don't even bother going to a dealer and asking for this part. I figured I would pick one up real fast at mine. Guy wanted 89 bucks!! add puking smiley face here.


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## TheRealist (Oct 28, 2009)

groggory said:


> The hockey puck thing (PCV Valve) would be a good thing to check. It should act as a one-way valve (engine -> intake). If you can blow (intake -> engine) that is bad. Basically your metered air from your MAF will now be allowed to flow into the crank case and valve cover which means the ECU's calculations will be messed up.
> 
> Check it out. It'd be nice if that were the problem.


Well I unhooked the PCV valve for a check up (black puck looking valve) and blew threw the hole (intake -> engine) and could cleary blow air inside. If that wasn't my problem then I think I found something that can certainly help my engine 

Thx for that post groggory. Will post when i have the fix done.


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## calvin_xl (Feb 21, 2007)

*timing advance mesure*

I am back home, so back in the car doing measures.

The graph below shows the N75, the RPM and the idle stabilizer (group 20).
I did these measure flowing atomic advice.

The goal was to check if there were a correlation between the value obtained and the boost surge.
According to Atomic the group 20 should not be higher than 5-6 degree.

The first run shows that the max value reached is 3 deg (in the small table), for the second run the value goes up to 5.3 deg on one of the cylinder.

One can definitely see that the N75 drop happen at the same time the group 20 values vary.

But I am not sure which event happen first (the n75 drop or the idle stabilizer).

Also the funny thing is that values are different depending on the cylinder (maybe due to the vag-com sampling rate).
I will read more on that.

If I can not find an explanation this week-end I will give 121$ to my favorite dealer on Tuesday for a new N75.


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## TheRealist (Oct 28, 2009)

calvin_xl said:


> If I can not find an explanation this week-end I will give 121$ to my favorite dealer on Tuesday for a new N75.


Thx for the results, I'll have to replace my pcv valve and see what happens. If nothing happens, then i'll assume its the N75.


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## forcefedjetta (Aug 14, 2003)

my car does this at the track top of 3rd and some times into 4th i think its my p-flow i installed a velosity stack so we'll see next week if it works


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## TheRealist (Oct 28, 2009)

but then again, it still could be anything... without those freakin codes we can't know for sure...


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## TheRealist (Oct 28, 2009)

groggory said:


> The hockey puck thing (PCV Valve) would be a good thing to check. It should act as a one-way valve (engine -> intake). If you can blow (intake -> engine) that is bad. Basically your metered air from your MAF will now be allowed to flow into the crank case and valve cover which means the ECU's calculations will be messed up.
> 
> Check it out. It'd be nice if that were the problem.


Quick question. I was reading up on the PCV, maybe im just confused.. but shouldn't it let a little air pass?
Just asking. Because I took it out of the inlet pipe and blew through that opening and could pass air to crankcase...

so time to change it?


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## cri-cri (Sep 27, 2009)

The *PRV* valve (aka puck valve located on the inlet pipe) is *NOT* a one-way valve. You should be able to blow air both ways, no problem. And yeah, I'm 100% positive as I changed it a couple of weeks ago.

*PRV* (Pressure Regulating Valve):









The *PCV* (breather) valve (located under the intake manifold) is a one-way valve. You should be able to blow air only one way (through the thick end of the valve).

Breather (PCV) Valve:


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## TheRealist (Oct 28, 2009)

Thank you for that correction Cri Cri


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## kay207 (Nov 20, 2009)

Does the PCV valve fail often?


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## groggory (Apr 21, 2003)

cri-cri said:


> The *PRV* valve (aka puck valve located on the inlet pipe) is *NOT* a one-way valve. You should be able to blow air both ways, no problem. And yeah, I'm 100% positive as I changed it a couple of weeks ago.
> 
> *PRV* (Pressure Regulating Valve):
> 
> ...


 What's the proper way ot testing both of these?


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## cri-cri (Sep 27, 2009)

@kay207: 
Mine was still working after 7 years although the spring inside was really weakened. I replaced it as I got the 034 PCV kit which includes a new one. 
@groggory: 
Not sure how to actually test the PRV... Some say 


> the valve closes with suction so unless you want to suck on it really hard, you won't be able to close it


 some others say 


> It will let air pass in both directions until a certain pressure


 I guess it's a matter of checking whether air still passes through and making sure it's not clogged up... As to the PCV, you should be able to blow air through the thick end but you should not be able to blow air through the narrow end. If it behaves like that it's OK, if not you have to change it.


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## TheRealist (Oct 28, 2009)

Question. 

Besides testing the N75 valve with a 12v batterie. Can i just put ignition on and listen for the "tic tic tic tic tic"?? 

If i should be hearing that tic with the ignition on, well... i'm not hehe 

Put ignition in, started tic tic ticing for 20 sec then stopped. 

Resistance on my N75 is still 29 so in range? they say 20-40 ohms... 

So what about that tic that stopped...


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## TheRealist (Oct 28, 2009)

cri-cri said:


> @kay207:
> Mine was still working after 7 years although the spring inside was really weakened. I replaced it as I got the 034 PCV kit which includes a new one.


 about that PCV... where the f is it? haha


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## Matt 337 (Apr 10, 2009)

I'm having this same problem, mostly in second gear, sometimes in first but always at low rpms.... 
I get intermittent misfire codes and my spark plugs have < 3000 miles on them.


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## calvin_xl (Feb 21, 2007)

*lambda value are ok*

I did more measures and the lamba values are fine ~1. and around .9 during hard accel which is close to the expected values. 
I have ordered the N75 and should get it Thursday. I will let you know.


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## TheRealist (Oct 28, 2009)

calvin_xl said:


> I did more measures and the lamba values are fine ~1. and around .9 during hard accel which is close to the expected values.
> I have ordered the N75 and should get it Thursday. I will let you know.


 sweet, thx dude


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## TheRealist (Oct 28, 2009)

*Check it out, that is what is happening*

Hey all, I found this video on youtube from a guy saying he had surging going on.. it is probably the closest example of what im getting althought i get it in 2nd, 3rd, 4th and 5th. (he gets it in 3rd). Guy said changing his N75 fixed it... 

watch and comment plz  

http://www.youtube.com/watch?v=8aWcwW3Lr50


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## calvin_xl (Feb 21, 2007)

*same here*

This is exactly my issue. I should get the N75 tomorrow and will do the swap in the evening when I come back from work. So we shall see


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## TheRealist (Oct 28, 2009)

calvin_xl said:


> This is exactly my issue. I should get the N75 tomorrow and will do the swap in the evening when I come back from work. So we shall see


 Hey I wanted to know, do you have any fault codes of any kind for the N75? or nothing at all, just the problem with no codes?


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## calvin_xl (Feb 21, 2007)

*fault code*

No fault code besides the usual misfire ones. I dismissed them since they seems to come from my wire harness being cracked and that during most of the runs none occurred.


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## TheRealist (Oct 28, 2009)

calvin_xl said:


> No fault code besides the usual misfire ones. I dismissed them since they seems to come from my wire harness being cracked and that during most of the runs none occurred.


 got it


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## calvin_xl (Feb 21, 2007)

*bingo N75 faulty*

Yahoo, it did it. My car is back, it runs like a champ. 
So in fact it was that stupid N75 also called solenoid valve by the dealer that was dead. 

In fact it was not completely dead, it work at the beginning when the ECU regulates it a 99-98% to build boost, but when the ECU tries to moderate it to regulate and stabilize the flow - which happens around 3000 RPM - the valve half starts to die. 

So I hope that will fix your issue too. 
Notice that my car is full stock, so I can no talk for people who have nods on theirs. 

Basicaly here is what it took me to find out : 

Changed the Y shaped tube for the cam case breather + the MAF + cleaned the TB. 
ThenI got the recall for the coils (didn't changed anything but it was free). 
And for the boost stuff, I cahnged the DV (but it was not that) and finaly the N75 and that was it. 

I had absolutely no error codes for the boost, the lambda reading were correct, the miss fire were just intermittent and due to my cracked harness so they were not the cause. 

Anyway, it just took me more than a month to find out and a lot's of reading but it was worth it. 

Now I just hope that I didn't prematurely damage my turbo by doing so many tests (but I do not thing so, anyway we will see). 

Good chance theRealist, it just cost me 121$ for the valve. 


PS: the test in the bentley manual is crap, they told you to mesure the resitance to check is the valve is fine. Except we the valve half-work, the resistance when it is breathing cold air is fine, but after the second run when the car is hot, it dies. This is why in one of my posts I realised that my first run leaving home was always fine, but after the symptoms were coming back.


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## Chodaboy1.8t (Jan 24, 2005)

*Fixed my issue as well...*

Thankfully along with a few on this thread, I was able to fix my issues as well. First thing I did was to put the stock N75 valve back on. That helped a little, but I still had the hesitation problem. That ended up being a vac leaked caused by a crack in my dip stick tube. Car runs great now. Hope this helps...


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## TheRealist (Oct 28, 2009)

Hey Calvin, I'm happy for you. hehehe 

So i just hope it is the N75 as my car is bone stock too. We'll see and i'll post any updates as soon as I have some. Thanx to everyone that contributed to this post as it was very useful for a lot of people. 

Updates will come on my part.


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## screaminseagull (Jun 15, 2002)

I have great news for a lot of people. I had the same symptoms as the original poster and i put in a new N75 valve and my car is running perfect again. Before my boost gauge showed 10 vac at idle and WOT 10spi down to 5 and up again etc. Now it reads 20 vac and holding 10 psi WOT.


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## TheRealist (Oct 28, 2009)

screaminseagull said:


> I have great news for a lot of people. I had the same symptoms as the original poster and i put in a new N75 valve and my car is running perfect again. Before my boost gauge showed 10 vac at idle and WOT 10spi down to 5 and up again etc. Now it reads 20 vac and holding 10 psi WOT.


 That is music to my ears. Thx for the post dude  That damn N75 hehe..


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## WeaselMF (Jun 9, 2010)

*You guys ROCK!!!*

I just bought a 2003 Turbo S, and have been plagued with this problem. I also was getting no codes and quit looking at the N75 because It tested fine with the meter. I was trying to figure out how to check the boost pressure sensor (located on the front of the intercooler). That thing is nearly impossible to get to, but now, I am headed to the parts place to get a new N75. Again, thanks to all for the info and the hard work.


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## TheRealist (Oct 28, 2009)

WeaselMF said:


> I just bought a 2003 Turbo S, and have been plagued with this problem. I also was getting no codes and quit looking at the N75 because It tested fine with the meter. I was trying to figure out how to check the boost pressure sensor (located on the front of the intercooler). That thing is nearly impossible to get to, but now, I am headed to the parts place to get a new N75. Again, thanks to all for the info and the hard work.


 I don't understand, it tests fine and you stopped looking at N75 but still going to change it? 
Tell us if ever you do change it if it fixed your problem  
I ordered mine.


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## calvin_xl (Feb 21, 2007)

*weird N75*

The Realist, IMF meant that he tested the N75 the way the manual recommends it. This is done with a meter to measure the resistance of the sensor. If you are between 27 and 40 ohms the N75 is supposed to be good.
I did it too and the readings were correct, this is why I stopped incriminating the N75.
It is only after having checked everything else that I came back to the N75. And guess what, I discovered that it starts to fail only when it starts to raise in temperature. I would bet that for a faulty one the resistance increase with the temperature and that the ECU signal can not drive it anymore which is why it gives up.
Bottom line, testing the N75 when it is cold is not an accurate test.


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## TheRealist (Oct 28, 2009)

Ok got it.

someone tried to steal my car this week-end.. 

He popped the cylinder and screwed my door handle completly... 400$ to change everything and reprogram..:banghead:

anyways... just wanted to vent a little haha 

Again, thx everything for their help


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## WeaselMF (Jun 9, 2010)

*Update on the 2003 Beetle Turbo S*

Well I got my new N75 solenoid today and promptly installed it, and guess what... It actually fixed the problem. It doesen't have the sudden surge of boost like it did before, but it also doesn't surge, which I am sure is a lot easier on the turbo. I am incredibly happy that ya'll helped me finally fix this problem. I, like many others, have spnt way way way to much time trying to figur this one out. Thanks again!


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## StillANoob (Dec 16, 2009)

had the same thing happen to me.... i changed my coilpacks and everything was perfect again....


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## thelettert (Sep 23, 2005)

anyone in here have any experience with other n75 valves dieing? 
im running apr program and audi TT n75j, and am experiencing the same hesitation as OP in second gear at low rpms. then it lets the boost out to 5psi n goes soft limp mode.


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## TheRealist (Oct 28, 2009)

thelettert said:


> anyone in here have any experience with other n75 valves dieing?
> im running apr program and audi TT n75j, and am experiencing the same hesitation as OP in second gear at low rpms. then it lets the boost out to 5psi n goes soft limp mode.


I dunno about that limp mode.. is it constant? or comes and goes?
Heard good things about the N75J Bosch valve.. should be a smooth ascention in boost..

If you have vag-com maybe try the same N75 log as Calvin?


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## thelettert (Sep 23, 2005)

its very random not consistant. but is often. been running n75j for years. boost delivery was great and only had problems during very cool weather (would overboost/hard limp)

now its back more often. sometimes it pulls amazingly hard and smooth all the way through second gear no problem. but sometimes if you go WOT at low rpm it will start to spool then stutter a bit back n forth, then let the boost out to 5psi. (thats soft limp right...)

so ur saying there is another n75j other than the TT... this bosch u speak of?

and have no acces to a vag com. could it be DV also? why would it only allow 5psi then? that could only be electronically limted. which is why i assume the n75 is getting stuck or something...


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## TheRealist (Oct 28, 2009)

Well, it seems you both are having the same problem as we are.. although I am not getting into limp mode (or so I think)
Just hesitation once in a while.


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## thelettert (Sep 23, 2005)

TheRealist said:


> Well, it seems you both are having the same problem as we are.. although I am not getting into limp mode (or so I think)
> Just hesitation once in a while.


well when you get the hesitation, and you continue to accelerate, after it finishes hesitating what does it do? continues at normal max boost? or does it let the boost out?


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## TheRealist (Oct 28, 2009)

Continues after it hesitates..I don't go into Limp mode
like I said before, it : goesssssssss stop goesssssssss stop goesssss

each hesitation being equally spaced in the RPM range and is almost or not noticeable at high RPM.


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## Sniped43 (Mar 30, 2009)

Me and a friend had the exact same problem, changed the MAP sensor on the intercooler and it went away instantly and pulled like normal. good luck.


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## silverstone18t (Aug 18, 2004)

Does anyone have the actual VW diagnostic procedures for surging? It seems like people have figured out MAF, N75, MAP, etc as the problem parts. Did anyone actually find these from a recommended diagnostic procedure? Or did all of this happen by trial and error?

If someone has an actual diagnostic procedure could they please post it, that would help alot.

For example if all you know is it is surging, what is the recommended first place to look? And when you look at it, how do you actually measure that it is good or bad? 

I know somebody on here must have the official diagnostic procedure.


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## Cryser (Sep 9, 2009)

silverstone18t said:


> Does anyone have the actual VW diagnostic procedures for surging? It seems like people have figured out MAF, N75, MAP, etc as the problem parts. Did anyone actually find these from a recommended diagnostic procedure? Or did all of this happen by trial and error?
> 
> If someone has an actual diagnostic procedure could they please post it, that would help alot.
> 
> ...


My understanding of the surging situation is this

VW doesn't have a surging diagnostic procedure because it doesn't happen at stock boost levels, Surging is caused when the turbo can not intake enough air for the amount of boost that it is producing. The reason this get fixed through so many different avenues(mainly change the N75 valve on nearly stock chipped cars) is the delay that these other valves have compared to the stock valve that is used. Personally I fixed my surging issues through the install of a silicone TIP and a BpI flowstack. The flowstack allows enough air in smoothly at the low RPMs while the Silicone TIP prevents the pancaking that happens with the stock TIP. I've driven in my car with a few people that have had surging issues and they have stated wear I can build boost in 5th gear below 2K they would being surging I attribute this to the flowstack allowing in more air then your standard intake with just a filter on the end of a pipe. When people fix it by replacing a sensor, more then likely the sensor was bad or going bad and relaying bad info to the ECU. When I bought my car the pervious owner had used a N7H "race" valve from ECS to stop the surging she was encountering from her GIAC chip. When I swapped back to the N75F valve I too had this surging issue, now with the flowstack and Samco TIP I can run the N75F valve just fine


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## TheRealist (Oct 28, 2009)

But the thing is, most people that posted here (and myself) are having surging issues with stock cars. 

My car is bone stock and Calvin's car is bone stock and STILL having the surging/hesitation issue..
I'm going to get my N75 valve today and install it and see what it does.

I'll post the results when i have tested my car to tell you if that fixed the problem. But i have to tell you having been to the dealer more than 5 times for this issue, no one, and I say no one has found anything on my car althought I know the hesitation is there.. (3 different dealers too)

So.. as you stated above.. it is only a problem when we go WOT and doesn't throw codes.. which makes it frustrating for ppl like me..

Anyhow.. i'll post when I'll have tested the beast.


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## Cryser (Sep 9, 2009)

How many miles are n the car, have you both looked over your ignition harness for cracks in the wires? Might be time for a coil recall(although they should have done that when you brought it to the dealer) or some new plugs


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## silverstone18t (Aug 18, 2004)

My car is probably pretty similar to most on here with issues:

90K miles
APR chip
APR DV
AFE drop in filter
0.72 5th gear swap
otherwise stock engine


I went 3-4 years stock no issues. Started surging a little. Performed the mod list above. Fine for 5-10K miles then surging again. Just recently surging bad on part throttle. Most noticeable at low RPM in 1st/2nd or 5th. At 3-4K RPM in 3rd/4th it does not happen, at least not much.

On a side note I blow a coilpack once or twice a year. I just replaced all 4 and it had no effect on the surging.


I am going to try the airflow mods of the TIP and velocity stack, I like those ideas for sure. 

But I guess my question still is, how do I reliably test the individual parts of the system to know if they have gone bad? VW should at least have recommended procedures for testing the sensors (other than the OBDII/VAG-COM method). There must be simple resistance measurements that can be made on some of them. It would be nice to have an idea if the sensor really was bad or not before just buying one to try it.

If it comes down to it and buying a new part to try it is the only way to go, which sensors/valves do you do first? Is this a good gameplan:

1. N75
2. MAF
3. MAP
4. Temp Sensor
5. Coolant Temp Sensor


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## TheRealist (Oct 28, 2009)

silverstone18t said:


> If it comes down to it and buying a new part to try it is the only way to go, which sensors/valves do you do first? Is this a good gameplan:
> 
> 1. N75
> 2. MAF
> ...


Well, 2 people here had the issue, changed the N75 and it fixed it. I haven't changed anything except cleaning fuel line/injectors, changing plugs, 1 coil. Other than that nothing else. Im going to get the N75 tonight.
MAF usually, and I say usually, gives out bad Idle.. but exceptions do exists.

Im going N75.
But honestly this type of problem is the worst in its class. no codes, intermittent. Its like a sleeping monster.
The MAP could be the problem too but its so hard to reach or test.. The n75 should have between 25-40 omhs of resistance.
Could be the Throttle body too, the alignement.

ill post when the n75 is changed..


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## TheRealist (Oct 28, 2009)

Coil recall was done.
Harness looks perfect but still wouldn't be able to see tiny cracks..


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## silverstone18t (Aug 18, 2004)

Cryser said:


> Personally I fixed my surging issues through the install of a silicone TIP and a BpI flowstack. The flowstack allows enough air in smoothly at the low RPMs while the Silicone TIP prevents the pancaking that happens with the stock TIP.


How did you mount the BPI flowstack? Do you have a short ram or a cold air intake making the install pretty easy? I'm using the stock box with a drop in AFE filter. Can the flowstack be used on a stock box and if so will it really make a difference there?


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## TheRealist (Oct 28, 2009)

*Final Update*

OK!
Updates.

N75 Changed. Pushed the car really hard for about 30 min and NO MORE HESITATION/SURGING.

For now.. haha!

I'll take it for another stroll tommorow as my problem came and went. But overall, smoother acceleration, harder pull and for a longer time.

It's not THAT noticeable (except for the hesitations that are gone), but like I said it still might not be the problem. So I give myself a couple of runs and I will definetly confirm things in a week or so.

Thanks to all that contributed to this thread.


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## silverstone18t (Aug 18, 2004)

TheRealist said:


> N75 Changed. Pushed the car really hard for about 30 min and NO MORE HESITATION/SURGING.



What N75 did you use? J, K, race, whatever?


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## TheRealist (Oct 28, 2009)

silverstone18t said:


> What N75 did you use? J, K, race, whatever?


Stock : *058 906 283F* which is the F version.


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## Cryser (Sep 9, 2009)

silverstone18t said:


> How did you mount the BPI flowstack? Do you have a short ram or a cold air intake making the install pretty easy? I'm using the stock box with a drop in AFE filter. Can the flowstack be used on a stock box and if so will it really make a difference there?


I just got a 2.5in -> 3in coupler from siliconeintakes.com and have it clamped directly to the MAF


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## TheRealist (Oct 28, 2009)

*Bottom line*

Bottom line is... for the particular problem, it was the N75 that was faulty and it wasn't throwing codes nor was the resistance out of play. 

Ask away if you want any clarification on the symptomes that I had.

Good luck to others.


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## calvin_xl (Feb 21, 2007)

*good news*

It was money well spent then.
Enjoy the car and do not get a ticket


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## Big_Tom (Aug 19, 2007)

i read your whole entire thread and i am having the exact same full throttle hesitation. i am hesitant to change my N75 because i'm not even using it. i have all the ports capped off and its still plugged in electronically and the problem presists. it's not there until the car is fully warmed up most of the time. i've replaced the plugs, new oem coil packs, new green top CTS, no MAF, new front o2 sensor, fresh mobil 1 oil. could a bad n75 cause problems just being plugged in?


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## TheRealist (Oct 28, 2009)

Well, I am wondering if one of the 3 ways is plugged in? is the long tip that goes inside the inlet pipe still in there?

Because if so, it surely still makes a difference even tho you unplugged the 2 other lines. but if nothing is connected to the n75 BUT the electrical connection, then.. I dunno...


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## TheRealist (Oct 28, 2009)

Big_Tom said:


> could a bad n75 cause problems just being plugged in?


I personally doubt it.


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## hootyburra (Feb 19, 2007)

It would be interesting to see what installing a MBC and eliminating the n75 would do to cure the problem.


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## Cryser (Sep 9, 2009)

Big_Tom said:


> could a bad n75 cause problems just being plugged in?


I don't see how if the only thing you have plugged in is the electrical connector and the other plugs are looped together or blocked off then the n75 can't control anything. There is no line running to the wastegate from the n75 so it can't control that.


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## Big_Tom (Aug 19, 2007)

I'm going to try completely unplugging my n75 today to see if that helps. i'll take a picture of the thing so you can see how i have it connected.


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## Big_Tom (Aug 19, 2007)

The Bay










The N75


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## alexlm (Feb 27, 2009)

Big_Tom said:


> The Bay
> 
> 
> 
> ...


how did it work??? I have a t3/t4 and I am having the same problem, but I have the n75 conected to my MBC so I what to try your setup.


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## Big_Tom (Aug 19, 2007)

well the car seems to run a little better since i unplugged the n75. my CEL is still there, but the hesitation seems to have subsided for the time being. it seems to have a bit smoother boost onset. I'm going to leave the n75 unplugged for now and we'll see what happens. i only drove about 20 mins so i think it's too soon to say if the problem is gone, but it certainly has not gotten worse with the N75 out of the bay completely


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## TheRealist (Oct 28, 2009)

Big_Tom said:


> well the car seems to run a little better since i unplugged the n75. my CEL is still there, but the hesitation seems to have subsided for the time being. it seems to have a bit smoother boost onset. I'm going to leave the n75 unplugged for now and we'll see what happens. i only drove about 20 mins so i think it's too soon to say if the problem is gone, but it certainly has not gotten worse with the N75 out of the bay completely


Have you watched the video that I posted in this thread? if so, is that the exact same thing that is happening? Plus, have you looked at the N75 duty cycle of Calvin?

Let me know.


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## Big_Tom (Aug 19, 2007)

i saw your video, thats not what my car is doing. my car used to do that when i was stock turbo on uni stage 1+. now i have having a full throttle hesitation where like if i floor it from a roll the car goes nowhere. its like all ignition/fuel is lost until i let off the gas then everything is normal again. if i ease into the gas all is fine, i just cant floor it immediately


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## TheRealist (Oct 28, 2009)

Big_Tom said:


> i saw your video, thats not what my car is doing. my car used to do that when i was stock turbo on uni stage 1+. now i have having a full throttle hesitation where like if i floor it from a roll the car goes nowhere. its like all ignition/fuel is lost until i let off the gas then everything is normal again. if i ease into the gas all is fine, i just cant floor it immediately


Then that has nothing to do with the N75..

I heard about softwares being updated (I assume you are flashed or chipped?)
Seems like its ECU related.

What about a Throttle body alignement? (since its driven by wire).
But definetly not a N75 Hesitation problem..


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## nick0188 (Nov 9, 2007)

I had similar problems and it was always the case that my map was covered in oil. I always said I'd never do it but I got a catch can and no more problems! Our PCV system is JUNK..


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## Big_Tom (Aug 19, 2007)

> Then that has nothing to do with the N75..
> 
> I heard about softwares being updated (I assume you are flashed or chipped?)
> Seems like its ECU related.
> ...


i do believe you are right about it not being n75 related in my case because im not even using the thing and havent been for almost 2 years now. my car seems not to care if i have the n75 plugged in or not. 



> I had similar problems and it was always the case that my map was covered in oil. I always said I'd never do it but I got a catch can and no more problems! Our PCV system is JUNK..


it's got to be my MAP sensor being covered in oil. at one point there was a fair amount of oil in my IC pipes. i did just install a catch can about a week ago. im going to remove it tomorrow and clean the thing and see what happens. or i might just buy a used one if the price is right


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## TheRealist (Oct 28, 2009)

Well if you suspect oil might be down there, taking out the MAP and cleaning it might be a good idea.
As good boost comes from good O2 sensor (front), N75, MAP, Coils, Plugs, MAF in general.

Let us know how it goes


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## John V (Jul 14, 2005)

Okay, I'm having this problem and don't know what to try next.

I have a 3" DP with cat to a 3" cat-back. Car was fine for months with this setup, but now it starts hesitating at WOT. It pulls very hard for a second, then feels like it misfires (it stutters and fails to accelerate smoothly, like it's hitting a fuel cut or hard timing retard) and then it accelerates but obviously at a much lower boost level. I do not have a boost gauge.

I replaced the N75 and I am having the exact same issue.

The car is a 2002 Jetta 1.8T. The PCV hose is in good shape. There are no stored codes. The CEL is not on (when I had coil pack problems before it would flash the CEL when it misfired). When I had O2 problems before the car threw a code.

Wouldn't a MAP, MAF or coil issue throw a code? Thoughts? This is driving me nuts!


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## TheRealist (Oct 28, 2009)

hmmm might be limp mode?
when you stop car and restart its all fine until you pull hard again and then does the same thing?


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## John V (Jul 14, 2005)

Not sure. If it were going into limp mode, would it not throw a code? No codes are thrown. And I'm not just talking about the CEL - I scanned for codes with a standard OBD-II reader and nothing is shown. 

Thoughts?


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## spa_bg79 (Dec 29, 2005)

*boost surge*

here is my video. same problem. 

http://www.youtube.com/watch?v=-MG19cR2a8A

should i change the N75. I got an N75 from a buddy an it was fine for a day. then it started doing it again. it's happening in WOT in 3rd, 4th and 5th.
chipped on UNI 1+, APR DV, no codes


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## TheRealist (Oct 28, 2009)

spa_bg79 said:


> here is my video. same problem.
> 
> http://www.youtube.com/watch?v=-MG19cR2a8A
> 
> ...


My that looks like the problem I had... but geez the fluctuation is faster in the video you posted.. I had 4-5 fluctuations in one full pull (lets say in 2nd).

how is your DV hooked up?


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## hootyburra (Feb 19, 2007)

it might be crazy but could this be from not having an anti buzz t fitting. sorry if that is a newb mistake on my part; but just a thought


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## TheRealist (Oct 28, 2009)

John V said:


> Not sure. If it were going into limp mode, would it not throw a code? No codes are thrown. And I'm not just talking about the CEL - I scanned for codes with a standard OBD-II reader and nothing is shown.
> 
> Thoughts?


As soft limp mode is a way to protect itselft, the car should normally give you a code of some sort. Yes.
So if no codes..its like the problem isn't big enough for the computer to alert you.

keep us updated on the symptoms..


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## TheRealist (Oct 28, 2009)

hootyburra said:


> it might be crazy but could this be from not having an anti buzz t fitting. sorry if that is a newb mistake on my part; but just a thought


What the deuce is an anti buzz t fitting? :sly:


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## John V (Jul 14, 2005)

So this morning, merging onto the freeway the car was more normal. It boosted up strongly for a couple seconds, then boosted down but pulled smoothly the entire way.

Normally this kind of move would make the car buck like it was hitting the traction control, but for some reason it was better today. Maybe because it was cooler? I only started noticing the fuel cut / throttle cut problem when it got really hot.

Is my 3" TBE causing the car to overboost and hit limp? I'm not super familiar with these cars and the search sucks at the moment. I do need to hook up a boost gauge to see if it's going over 15psi. But why would that be happening?

Hoping someone has some more insight into this.


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## Big_Tom (Aug 19, 2007)

so i cleaned my MAP sensor today and double checked all my IC clamps and what not. the problem still exists. the car drive perfect until i reach the 190 on the temp gauge and the car is fully warmed up. it seems like the longer i drive and the hotter it gets the worse the misfires are. i dont think its MAP or N75 related now. its tolerable at its worst, the CEL doesnt blink and it doesnt disrupt daily driving much but it is present, noticeable and annoying to me:banghead:


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## hootyburra (Feb 19, 2007)

TheRealist said:


> What the deuce is an anti buzz t fitting? :sly:


http://www.boostcontroller.com/index.php?item=161

I know I have read about it before in this forum. 

Just a thought.


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## silverstone18t (Aug 18, 2004)

TheRealist said:


> What the deuce is an anti buzz t fitting? :sly:


The anti buzz t fitting is a "special" T fitting for mechanical boost gauges. The anti buzz part of it means it restricts airflow a little. So when lifting the throttle for example and the boost starts to fluctuate, the pulses are somewhat restricted by the fitting. The boost gauge gets a "filtered" air pressure signal so it doesn't buzz (or in reality just buzzes less).

But the amount of air that flows through this tube to the boost gauge should be tiny, basically none, unless you have a leak in this line. So this shouldn't affect this problem at all.


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## TheRealist (Oct 28, 2009)

Big_Tom said:


> so i cleaned my MAP sensor today and double checked all my IC clamps and what not. the problem still exists. the car drive perfect until i reach the 190 on the temp gauge and the car is fully warmed up. it seems like the longer i drive and the hotter it gets the worse the misfires are. i dont think its MAP or N75 related now. its tolerable at its worst, the CEL doesnt blink and it doesnt disrupt daily driving much but it is present, noticeable and annoying to me:banghead:


Dude do you have Vag-Com?

What about the Temp sensor? 
Have you checked it out?


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## Big_Tom (Aug 19, 2007)

naw i dont have a vagcom. also i cannot get anyones scanners to read my ecu. it wont connect. im DP'd in the ass right now. also the coolant temp sensor is new. the only sensors im using that arent new are my IAT and MAP


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## TheRealist (Oct 28, 2009)

Big_Tom said:


> naw i dont have a vagcom. also i cannot get anyones scanners to read my ecu. it wont connect. im DP'd in the ass right now. also the coolant temp sensor is new. the only sensors im using that arent new are my IAT and MAP


Well one of those 2 could be the problem.. try testing both and see if they are in range (resistance)


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## Big_Tom (Aug 19, 2007)

I finally got my friends vagcom to work. 


Wednesday,30,June,2010,21:23:12:52081
VCDS Version: Release 908.0
Address 01: Engine Labels: 06A-906-032-AJQ.lbl
Control Module Part Number: 06A 906 032 HR
Component and/or Version: 1.8L R4/5VT G 0007
Software Coding: 07500
Work Shop Code: WSC 79667 
Additional Info: XXXXXXXXXXXXXXXXX XXXXXXXXXXXXXX
12 Faults Found:
16622 - Manifold Pressure / Boost Sensor (G31): Signal too High
P0238 - 35-00 - -
16490 - Manifold / Barometric Pressure Sensor (G71) / (F96): Implausible Signal
P0106 - 35-00 - -
17763 - Cylinder 1 Ignition Circuit: Open Circuit
P1355 - 35-10 - - - Intermittent
17766 - Cylinder 2 Ignition Circuit: Open Circuit
P1358 - 35-10 - - - Intermittent
17769 - Cylinder 3 Ignition Circuit: Open Circuit
P1361 - 35-10 - - - Intermittent
17772 - Cylinder 4 Ignition Circuit: Open Circuit
P1364 - 35-10 - - - Intermittent
17704 - Error in Mapped Cooling System (check Temp-Sensor and Thermostat)
P1296 - 35-10 - - - Intermittent
18057 - Powertrain Data Bus: Missing Message from ABS Controller
P1649 - 35-10 - - - Intermittent
17968 - Maximum Engine Speed Exceeded: Engine Warranty VOID! 
P1560 - 35-10 - - - Intermittent
17511 - Oxygen (Lambda) Sensor Heating; B1 S1: Performance too Low
P1103 - 35-00 - -
16519 - Oxygen (Lambda) Sensor B1 S1; Heating Circuit: Malfunction
P0135 - 35-10 - - - Intermittent
17956 - Boost Pressure Regulation Valve (N75): Open Circuit
P1548 - 35-00 - -
Readiness: 0000 0000

all but the top 2 were cause by me unplugging things to test except for the top 2 faults. i think i need a new MAP


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## TheRealist (Oct 28, 2009)

Big_Tom said:


> all but the top 2 were cause by me unplugging things to test except for the top 2 faults. i think i need a new MAP


Bingo.


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## Soze.K (Mar 15, 2009)

Had the same problem...


Coil packs


Change em..


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## ProtectedBy9mm (Mar 11, 2010)

So did it end up being the MAP?? And when you say MAP, are you talking about the one in the Intercooler? i asked my mechanic to about it, cause i have the EXACT problem as OP, and he said ,"iv never fixed anything by replacing a/the MAP sensor.." that kinda pissed me off.

Thank you.

PS:
New coils
N75J
NEW K03s
2.5" CB
intake
possibly a chip/tune: I have no idea, it gets codes but no CEL, EVER.


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## 20V GLI (Apr 14, 2009)

*Full-Throttle-Hesitation*

My car has this same problem on my 04 gli with CEL but it also leaks antifreeze but the tempature gauge shows normal readings. this happens after car is truned off.



bass_4_ever said:


> this happened to me... i changed the coilpacks, spark plugs, gaps, maf, etc. I was told to change the 02 sensors (front & rear) as well as the *TEMPERATURE SENSOR*. My car no longer misfires. I checked it out with a vag-com, aparently my temperature gauge was reading 90 degrees inside the car. With a vag-com, the temperature was reading @ 78-85 degrees and not warming up anymore. Turns out my temperature sensor was reading the engine was cold and needing to warm up. So it was feeding more gas than needed into the engine to compensate for the cold engine. After changing my 02 sensors & temperature sensor (not thermostat) the car runs like a champ! Good luck!


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## TheRealist (Oct 28, 2009)

check level and pressure test it. it might be too full.. like mine was :sly:


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## ProtectedBy9mm (Mar 11, 2010)

Well, i found MY problem....

The "arm" that connects the wastgate rod to the "door", inside the exhaust outlet on the turbine has TONS of lateral play. So when the turbine is cold, cold car, the door will open and close fine. but when it warms up, the metal expands and the door can not create a seal.

yea, fun stuff. turbine had less than 2k on it, and thats PROBABLY what blew my OE engine 2 months ago.


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## mk4doorigami (Jun 28, 2007)

*same thing was happening to me*

change the MAF sensor:thumbup:


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## viasevenvai (May 8, 2006)

I have a similar issue. When my car does it it usually throws the traction light on. When I press the ESP button to turn the traction light off (traction control back ON) it won't go off, it's like the computer got mad that I went full throttle and glitched. I have to turn the car off to get the ESP button to work again.

I think the ABS sensors shouldn't be ruled out, or perhaps something with the differential can cause this?


I have new plugs and coils. My fuel filter and pump are still brand new from my stg III kit also. I've cleaned my MAF about 40,000 miles ago.

My car does it pretty predictably in 3rd gear usuallly, I just throttle through it though and nothing bad happens.


I'll let you know if I find the problem.


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## bazz780 (Aug 11, 2004)

hey guys, hope you can help, i actually have intermittent power loss on my car (remapped audi S3), it pulls really well at times with no problems and no sound of boost leak, and other times it 'whooshes' like boost is leaking when i try to accelerate hard WOT or if im accelerating in higher gears at low revs and the car feels like its not pulling well, could it be N75 or the hockey puck thing?, i checked for leaks and there aint none, i dont believe its the DV and as the problem is intermittent must be an electrical issue? 

On vagcom car is running at 220bhp but mine has been remapped, i have not had a chance to do a data run when car is behaving to see if it produces more bhp. 

please help as its driving me barmy! 

thanks


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## Marcio (Sep 4, 2009)

my car done that one time, the abs and traction control lights came in at the same time just after I started the car. rought idle too.
i just turn it off, turn the ignition on again and wait about 10 sec, i could hear the eletronic throttle open and closing by itself (self alignment). then it just went back to normal.
I soon predicted my battery was going dead, so the ecu need to align the throttle almost everytime.
turns out the previous owner had changed the battery for and new one, but out of specification.
changed the battery and never got it again.

back to the topic related problem.
ive got an 05 chipped GTI.
had the same surging boost problem.
changed the n75 for the J one. i know it suposed to be the "racing one" but it feels much smooth than the factory F (maybe it was broken anyway)
it wont surge anymore and until now (about 2 weeks using it daily) never reached limp mode.





viasevenvai said:


> I have a similar issue. When my car does it it usually throws the traction light on. When I press the ESP button to turn the traction light off (traction control back ON) it won't go off, it's like the computer got mad that I went full throttle and glitched. I have to turn the car off to get the ESP button to work again.
> 
> I think the ABS sensors shouldn't be ruled out, or perhaps something with the differential can cause this?
> 
> ...


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## ScubaStevo87 (Aug 9, 2010)

I was having this same problem when I first bought my 01 1.8t. I changed the plugs, coil packs and fuel filter and it reduced the frequency but didnt fix the problem. Went and got a REVO software trial put on my car... BAM. Didn't do it anymore and even since the trial has run out it has run 100%. 

Probably just luck (or a coincidence) for me but there's my $.02.


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## Entiz (Nov 22, 2004)

Had the same issue on my car. 

Cleaned the MAF - No change
Replaced N75 - No change
Corrected gap on spark plugs to .028 (chipped) - Worked


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## Ross08 (Jul 26, 2011)

hey guys dont mean to bring this thread back from the dead but im currently experiencing surging with my car. here is my story 

put my air in and then few days later car was surging and jerking as i applied throttle. 
- eventually just turned into car would idle like crap. unplugged the maf car idled but still had that cut when you applied gas. 
- Bought a new maf and it didnt help right away but symptoms got better. I could drive but not put the pedal down or in low rpms the car would jerk * although all codes had went away ( which were codes for MAF and knock sensor). 

- got it home and then bam idled like crap again. Although no codes this time. 
- Replaced spark plugs and car runs fine. (besides the cut out when the pedal is floored)


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## Big_Tom (Aug 19, 2007)

MAP sensor... that's what fixed my problem


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## Ross08 (Jul 26, 2011)

i had a map sensor problem and it ran a code. not like this though. it feels like the fuel. And its weird how replacing spark plugs made it a million times better.


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## SCK (Jul 13, 2000)

Chodaboy1.8t said:


> Thankfully along with a few on this thread, I was able to fix my issues as well. First thing I did was to put the stock N75 valve back on. That helped a little, but I still had the hesitation problem. That ended up being a vac leaked caused by a crack in my dip stick tube. Car runs great now. Hope this helps...


Sorry for bring this thread alive... Had similar issue for months, hesitation when engine is warm between 2000-3000 rpm. Planning to get a new N75 but I also noticed the dip stick tube is broken (more than just a crack). I've never thought that could be a problem thou. Is it easy to replace the dip stick tube?


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## SCK (Jul 13, 2000)

Just found the answer to my own question. 

http://forums.vwvortex.com/showthre...ick!-Why-you-are-having-problems!-Pics-inside!


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