# HELP: Vrt issues - Breaks up at 4000 rpm



## brandon0808 (Mar 19, 2009)

The setup:
9:1 head spacer
4" maf housing
kinetic manifold
kinetic 3" downpipe
MBS 3" exhaust
brand new as of 5/11/13 Tial 38mm wastegate . 8.7 lb spring
greddy rs bov - recirculated
all welded aluminum intercooler piping
c2 42# software
bosch green top injectors- 42#
rotomaster turbo ( some of this was from a kinetics kit)
ngk bk7 plugs gapped to .024

What the car is doing:
I got the car on the road a few weeks ago and the car wasn't running right, it wouldn't pass 4k and would buck/ pop/ hesitiate like a mother. I boost leak tested it found a bunch of leaks. My most solid solution was to get the piping welded to prevent future leaks.

Once the piping was welded together the car would pull up to roughly 4500 rpm but nothing more than that. Fast forward to the middle of this week and the car started pulling up until ~ 6000 rpm, after that I felt as if it wasn't making power. 

I suspected maybe the old tial was the culprit ( it had a 6 lb spring) as I wouldn't ever see 6lbs on my boost gauge, only 4-5. 

Yesterday I put on a new tial wastegate and the car is back to only making 4000 rpm, once I hit 4000 rpm it bucks violently, hesitates, and I can hear a loud rush/ pop of air.

After some more research last night I plan on changing my fuel filter today and I want to buy an aeromotive stealth in tank pump in the near future.

The car starts, idles, and runs great up until 4000 rpm.

I will appreciate any suggestions and will provide more info or pics if needed. I really want to get this thing running right. Thanks in advance.


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## PjS860ct (Dec 22, 2002)

try lowering plug gap and ground 1 of the coilpack bolts to the car


Post a couple of pics of your setup as well


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## the mad conductor (Nov 12, 2009)

Def regap the plugs and run copper plugs. 


Sent from my iPhone while inside your mom


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## Norwegian-VR6 (Feb 6, 2002)

Check that you have a 3bar fpr.


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## brandon0808 (Mar 19, 2009)

Here are some pics
new tial


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## brandon0808 (Mar 19, 2009)

PjS860ct said:


> try lowering plug gap and ground 1 of the coilpack bolts to the car
> 
> 
> Post a couple of pics of your setup as well


I will give this a try , hopefully tomorrow or the day after. What should I gap them to? .020?



the mad conductor said:


> Def regap the plugs and run copper plugs.
> 
> 
> Sent from my iPhone while inside your mom


What plugs do you recommend? I'm running these NGK BKR7E



Norwegian-VR6 said:


> Check that you have a 3bar fpr.


Will do thank you!!


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## masterqaz (Oct 5, 2007)

Bkr5e are copper plugs. They'll be fine. Just setup the gap. 

What's the afr up top when it bucks.


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## ChrisJGuzman (Apr 13, 2002)

Ever clean the air filter?


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## PjS860ct (Dec 22, 2002)

also if you can move the filter away from the MAF housing the air has a little more time to straighten out before it goes pass the sensor.. 

.020 is fine...

clean setup btw :thumbup:


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## brandon0808 (Mar 19, 2009)

I should have some time Thursday to work on the car a bit. I picked up some ngk bk5's, a fuel filter, and I plan on running that extra ground. I'll report back with the results!


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## PjS860ct (Dec 22, 2002)

Why did you get the bkr5e plugs? ^^^

Those are hot plugs. Keep the bkr7e that's in there now and just re gap closer.
Ngk= higher the number the colder it is n is best for turbo cars... 
Lower the number the hotter it is... ngk5 is stock plugs


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## brandon0808 (Mar 19, 2009)

PjS860ct said:


> Why did you get the bkr5e plugs? ^^^
> 
> Those are hot plugs. Keep the bkr7e that's in there now and just re gap closer.
> Ngk= higher the number the colder it is n is best for turbo cars...
> Lower the number the hotter it is... ngk5 is stock plugs


I picked those up because my local autoparts store had them and since they were recommended. I'll return them though. 



Norwegian-VR6 said:


> Check that you have a 3bar fpr.


Forgot to do that today :banghead: I knew I was missing something. I will have to check tomorrow, this is my reminder. 



masterqaz said:


> What's the afr up top when it bucks.


No wideband so I'm not sure.


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## brandon0808 (Mar 19, 2009)

So I pulled all of the plugs today and cleaned them off. I took the gap down to .020 . I also added a ground from a coilpack bolt to one of the ground bolts on the transmission. I forgot to check which fpr so I will do that tomorrow. The air filter is also pretty clean. 

The car is still doing the same thing, sometimes it will buck, others it will not. Sometimes it will make a pop noise (boost going somewhere I assume) at 4k rpm and other times it will rev a little past 4k rpm but the power just doesn't seem to be there. I can try to take a video of what it is doing if that will help. It also feels to be a little slower with this different gap but I didn't get a chance to drive it a whole lot with this new gap. I will report back tomorrow.


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## TBT-Syncro (Apr 28, 2001)

brandon0808 said:


> So I pulled all of the plugs today and cleaned them off. I took the gap down to .020 . I also added a ground from a coilpack bolt to one of the ground bolts on the transmission. I forgot to check which fpr so I will do that tomorrow. The air filter is also pretty clean.


running 30+ psi? if not, there is no reason to run a gap that small. all you're doing is hiding the real cause.

p.s. i run 20 psi at .028 (used to run .032 fine)


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## Norwegian-VR6 (Feb 6, 2002)

Bosch F3Cs plugs from Ebay with no gapping and check your fpr. Then buy a wideband.
:beer:


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## the mad conductor (Nov 12, 2009)

^^ def get a wideband. need to figure out what your AFRs are when this is happening.


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## brandon0808 (Mar 19, 2009)

TBT-Syncro said:


> running 30+ psi? if not, there is no reason to run a gap that small. all you're doing is hiding the real cause.
> 
> p.s. i run 20 psi at .028 (used to run .032 fine)


Only at 9lbs of boost right now. I will buy an aermotive stealth pump in the near future so that I can crank the boost up. I just want to figure this out beforehand. 



Norwegian-VR6 said:


> Bosch F3Cs plugs from Ebay with no gapping and check your fpr. Then buy a wideband.
> :beer:


I'll have to look into those plugs.



the mad conductor said:


> ^^ def get a wideband. need to figure out what your AFRs are when this is happening.


What one do you reccomend?


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## Norwegian-VR6 (Feb 6, 2002)

Ive used mine AEM Uego since 2009. No issues. Easy. Bought it from Summit


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## brandon0808 (Mar 19, 2009)

I checked and I have a 3 bar fpr. I reset the ecu and went through a few fan cycles, I don't think its any better yet but I should know more tomorrow. 

Should I try some different plug gaps? My chip in a different ecu? Are there any sensors I should test? Or should I just be easy on it and buy a wideband?


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## wabbitGTl (Jan 2, 2007)

I've been watching this as I've been plagued with a similar issue on my car. I believe we have it isolated to a break in the wiring somewhere from the crank sensor. I replaced the sensor and have the issue still. Same thing, car runs great until roughly 5000rpm and then spits, sputters, backfires, etc. May not be the issue but worth a try. That wiring is sensitive to electrical interference, so any break in the wiring or shielding can cause problems.


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## brandon0808 (Mar 19, 2009)

wabbitGTl said:


> I've been watching this as I've been plagued with a similar issue on my car. I believe we have it isolated to a break in the wiring somewhere from the crank sensor. I replaced the sensor and have the issue still. Same thing, car runs great until roughly 5000rpm and then spits, sputters, backfires, etc. May not be the issue but worth a try. That wiring is sensitive to electrical interference, so any break in the wiring or shielding can cause problems.


When it hits 5000 rpm do you hear a loud pop (like the boost is going somewhere) 

I think I'll rent a fuel pressure tester and go through the Bentley to test the engine sensors. My car ran great n/a last year though. Post a pic of your setup


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## Norwegian-VR6 (Feb 6, 2002)

Does the "poop" sound come from the airfilter? Like sometimes when I rev my car it can do that. With 4" maf and with the Pro-maf. I dont have any issues, just saying that it can make this sound when reving it high when in neutral.


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## wabbitGTl (Jan 2, 2007)

Can't post pics from work, sorry. I'm running Lugtronic's VEMS Standalone, so I can log almost everything aside from fuel pressure (I will be able to log that soon) and I don't have any issues losing boost when this happens, it just hits a brick wall. It runs great up until that point and pulls hard, and then take a crap. I don't have a MAF anymore though, thankfully


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## brandon0808 (Mar 19, 2009)

wabbitGTl said:


> Can't post pics from work, sorry. I'm running Lugtronic's VEMS Standalone, so I can log almost everything aside from fuel pressure (I will be able to log that soon) and I don't have any issues losing boost when this happens, it just hits a brick wall. It runs great up until that point and pulls hard, and then take a crap. I don't have a MAF anymore though, thankfully


That seems to be what mine is doing, do you have a wideband? If so what does it show when you hit the "brick wall"



Norwegian-VR6 said:


> Does the "poop" sound come from the airfilter? Like sometimes when I rev my car it can do that. With 4" maf and with the Pro-maf. I dont have any issues, just saying that it can make this sound when reving it high when in neutral.


The pop seems to be coming from the wastegate area. It could be the bov but its hard to tell while driving, it will pull great up until 4000 then pop / not rev past 4000 unless its in neutral , or less than full throttle. I put 125 miles on it today and it's starting to clear up.I think tomorrow I'll put the plug gap up to .024 and keep driving it. As of now it will pull up to around 5000 rpm.


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## wabbitGTl (Jan 2, 2007)

I had a terribly functioning wideband at the time and it would always spike rich, but I didn't trust it. I think we have the issue solved, but we'll find out soon. I haven't driven the car since October :facepalm:


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## brandon0808 (Mar 19, 2009)

Let Me know what you come up with. I'm almost leaving toward my issue being a misfire now after my ride home last night.


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## Slayer (Aug 8, 2000)

This might be a dumb question, but are you running an open dump / screamer pipe off that tial? or does it recirc back into the downpipe? The kinetic dp looks like its a recirc with a flange on it, but your pic shows like 1ft of flexible pipe on it?

If you're doing an open dump, maybe it's sucking the exhaust fumes into the intake when the wastegate opens?


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## brandon0808 (Mar 19, 2009)

Slayer said:


> This might be a dumb question, but are you running an open dump / screamer pipe off that tial? or does it recirc back into the downpipe? The kinetic dp looks like its a recirc with a flange on it, but your pic shows like 1ft of flexible pipe on it?
> 
> If you're doing an open dump, maybe it's sucking the exhaust fumes into the intake when the wastegate opens?


No dumb question, I could have overlooked/missed something very simple :laugh: 

To answer your question: It is recirculated into the downpipe with that flex pipe. 

On my way home today I experienced the popping sound at 3000 rpm even. I'm leaning toward it being a misfire, I think the pop is either a backfire or something odd happening with the boost when the car misfires?


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## R32Smoker (Oct 21, 2010)

I've been struggling with a very similar issue for a couple years now. When I first bought the car it had a C2 630 tune and would "pop" like you describing on cold starts while idling and whenever I would turn the boost up past 16 psi. I swapped to the United Motorsports 630 and the car never "popped" on cold starts again, but still misfires/hesitates/pops when the boost is cranked up.

I've replaced just about everything I can think of trying to solve the problem; different plugs at various gaps, new wires, coilpacks, sensors, stiffer wastegate spring, checked for boost leaks and vacuum leaks, and different tunes.

I ended up doing the Ford Mustang Screamin Demon coilpack swap, and it helped out a bit. Runs smoother and misfires less, but I think this was more of a bandaid than actually fixing the problem. With this coilpack my car seems to like BKR7E plugs at stock gap (around .034) the best and actually runs worse when gapping any tighter that .025

I decided to try out a different tune last month since the UM tune runs a bit rich and other people have been having similar issues as well, so I bought a Unitronic 630 tuned ECU from a known good running VRT. Swapped in the ECU along with an A8 maf housing and 4 bar FPR. Weirdness insued....

On the Unitronic tune, it now misfires/hesitates/pops at partial throttle around 2-4K rpms. The UM and C2 tune never did that, only at full throttle once full boost kicked in at 4K rpms. It doesn't run as rich though, the UM tune threw system too rich codes. The Unitronic tune threw this code, 17551- Load Calculation: upper limit exceeded. Apparently this code means the ECU is seeing more air than it expects?

If this tune ran fine on a similarly built VRT, I guess this means the problem is in the hardware somewhere?


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## brandon0808 (Mar 19, 2009)

R32Smoker said:


> I've been struggling with a very similar issue for a couple years now. When I first bought the car it had a C2 630 tune and would "pop" like you describing on cold starts while idling and whenever I would turn the boost up past 16 psi. I swapped to the United Motorsports 630 and the car never "popped" on cold starts again, but still misfires/hesitates/pops when the boost is cranked up.
> 
> I've replaced just about everything I can think of trying to solve the problem; different plugs at various gaps, new wires, coilpacks, sensors, stiffer wastegate spring, checked for boost leaks and vacuum leaks, and different tunes.
> 
> ...


So to this day you still have the issue? I don't want to throw all these new parts at it like many people do for it to not fix the problem. I know that my fuse box is a little corroded from when the cars windshield frame was rusty ( I replaced that right away) So tomorrow I plan on swapping in a corrosion free fuse box. ( car ran fine na though) It may or may not fix the issue but it will be good for peace of mind. 

I rented a compression tester today and will try to get that done tomorrow. I also want to test my fuel pressure. After those tests I will probably start testing voltage at various sensors and test the sensors to see if they are within spec or not.


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## R32Smoker (Oct 21, 2010)

Yep, my car still misfires under high boost levels, and occasionally misfires on low boost. Most of the time it runs ok as long as I don't crank the boost up. Thing is though my motor is fully built with 8:1 compression and should be able to run 20+ psi no problem. Not sure what else to do at this point


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## brandon0808 (Mar 19, 2009)

I rode in a buddies mk3 vrt today and all I can say is I can't wait to get mine running right. He's on standalone and the car runs amazing. I took him for a ride in my car and he's pretty sure that it's a fueling issue. I still plan on doing the fuel pressure test but it looks like I'll be replacing my fuel pump sooner than I expected. While we were driving around I also ran into someone else I know with basically the same setup I have other than him having better fueling and a short runner. 

After talking to the two guys I think I'm going to:
test the fuel pressure before and after a new fuel filter
get an aeromotive stealth pump (run in tank)
and some sort of aftermarket fuel rail (both guys recommended/had one)


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## brandon0808 (Mar 19, 2009)

So I did a fuel pressure test, here are the results:



With fpr disconnected:



I changed the fuel filter after the test and there wasn't any increase in pressure. Looks like I need a new fuel pump! Hopefully that is the only issue. I'll pick up a aermotive stealth pump in a few weeks and throw it in.


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## brandon0808 (Mar 19, 2009)

new fuel pump fixed the issue!! To anyone with a similar issue, I highly recommend the aeromotive stealth pump swapped into the stock sending unit. No worries about two pumps then or if your in tank pump isn't feeding your inline pump.


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## TBT-Syncro (Apr 28, 2001)

i'm confused. your fuel pressure readings were exactly correct.


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## brandon0808 (Mar 19, 2009)

Bentley calls for 51 pounds at idle and 56 with the fpr vacuum unhooked?


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## 2.0 Ho (Sep 27, 2006)

On obd1 yes. obd2 is 3 bar and only 43.5psi


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## brandon0808 (Mar 19, 2009)

Well regardless the old pump was worn out and this new pump has fixed my problem 100%.

For those with an inline pump having possible fueling issues, I highly recommend the aeromotive stealth pump.


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## dubbin95 (Mar 18, 2007)

Psi doesn't mean anything unless you have flow. He had psi but no flow to keep them fed up top


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## EL DRIFTO (Jul 11, 2004)

i think you can verify flow volume per the book after the regulator which confirms flow @ pressure


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