# Looking to pick a few minds (MKIV 1.8t Diagnostics info needed)



## stockstatus (Jun 4, 2012)

I am new here and have posted a few times before since I bought my 2001 1.8T AWD engine code Jetta. 

The issue I am having is this. (a bit of a read. No really its long) 

The previous owner warned that a EPC would come and go but no CEL 
I thought ehh its worth it, I want a jetta and this is a good deal. 

Car ran fine for the first few weeks, but I wanted cool pshh pshh sounds, So a gentleman on JJ hooked me up with a brand new forge DV spltr. 
I installed it in about 5 min and set it to 12 clicks (guys at forge said this was a great starting point) it ran fine. 

Then one morning I went out to start it and it was idling all over the place and scared me, my mysterious new Jetta was messing up and I have been living under a rock since I was 11 years old I owned a 76 camaro z28 and a 94 mustang with a custom supercoupe swap and I built both of these, so diagnostics was a cake walk. 

I called a shop in town they were a huge help over the phone and I eventually took the car to them and they were able to diagnose a boost leak, implausible signal issue to TB and faulty PCV system. Before taking it in I replaced the stock DV just to see if they would claim it faulty. 

800 dollars and about 2 weeks later I had my Jetta back. 

It drove great, I started to notice a small thump from the exhaust as the days passed so I had a set of coils/plugs that i ordered from ECS and decided to throw those at it. 

I have noticed the small thump since mostly in the mornings and only at idle. 

I was driving at one point and a EPC and check engine light came on and I returned to the shop to have it read. I was told it would be a few weeks before they could diagnose and that it was a static vac leak and pressure loss between turbo and TB valve. 

I decided since I eventually want to get a APR tune I can just go ahead and install my boost gauge, and it can help me see if there are any needed adjustments on the DV and also be able to tell if i go in soft limp before the EPC pops on again. i went to soft limp a few times over the next couple days. i also noticed a very eratic needle during vac. at idle. boost didnt seem to get quite past 6.5 

I also while under the hood at some point after, noticed fluid at the base of the injectors oily substance (thought to be gas). I made my way down to the parts store and purchased O rings after a quick Google and confirm of these causing such a problem. I changed the upper o rings and left the lower due to the fact that the lower o rings are not easy to find in parts stores, at least they aren't listed. 

I did however soak the used ones in some synthetic oil to liven them up till i can find the proper part number. 

The night I changed the O rings I went to a 311 concert about 55 miles from home, After the concert I was ready to leave cranked the car and the idle was horrible fromt 2500 to 600ish and the EPC ASR and CEL were illuminated. 

I panic'd a bit stared under the hood for a while and decided to cycle the ignition on and off a few times, this seemed to work I was able to get a somewhat decent idle and make my way through the traffic before it popped the epc in which case i pulled into a lot and let it clear. 

the next day it started up and idled rough but got me to work, on the way home I had to hold my toe on the gas to keep it running at stops and when stopping (not easy in a manual) or it would die out. I called the mechanic at the shop and made arrangements to bring it in that evening. 

On the way to the shop it was a gem I questioned having to take it in, but decided it best for the long run. 

4 days at the shop and they made time for me, claimed the throttle body was now the problem and they could not diagnose the static vac leak or pressure loss due to modifications. (begin small rant) Now I don't consider a boost gauge and a DV too drastic a modification but the owner made it very clear he had no interest in finding the issues and even recommended a shop one town over. I am not upset at all about them not being able to find the issue but to blame it on the Mods? really? 
(end small rant) 

So they replaced the TB and set the readiness codes while I was in school today and my GF was able to go by and take care of the bill and get the keys. 

Tonight we picked it up and I get in and it starts up great and then about 5 seconds of running....... CEL...... seriously and then oh yeah they didnt want to trace the vac leak issue. 
it just sucks to have invested 1400 in repairs and feel as though I got no where. 

the car seems to idle fine (very small variation, when stopping it will drop down below 800 and then return), gets full boost and has plenty of power, it just that CEL is going to bugg the mess out of me. 

So where should i begin diagnosing the issue, and does this seem like the tail tail signs of anything other than me being a noob and not knowing enough about the platform. i have very limited access to vag com via school (NTI) and will also be inquiring with an instructor about some pre class fun in the lab with this. 

And if you read all this, You are a trooper thank you for helping. I will have the CEL codes read in the morning and update this to confirm the CEL is a vac/boost issue. 

again Thanks for reading and any advice is welcome


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## Rockerchick (May 10, 2005)

Where in NC are you/what shop did you go to?


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## stockstatus (Jun 4, 2012)

I dont wanna disclose the shop bc the technician was a huge help, for the most part. The p0113 was the cel and i say the technician was a help for the most part because after reading the code i popped the hood and the iat was unplugged what a goof lol. I'm. In the salisbury area btw. Just north of Charlotte. 

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## stockstatus (Jun 4, 2012)

Hope im not speaking too soon but the car is running great
Still want to swap out those lower o rings on the injectors

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## Rockerchick (May 10, 2005)

I know of a few shops in the general area out there, but it would be good to know where you went.


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## OddJobb (Nov 6, 2004)

Before you threw all that money at the car, you should have found someone with VCDS to scan it. This would have at least pointed you in the right direction without all the guessing. Hell, with all the money you spent already, you could have bought a genuine Ross-Tech cable.


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## speedtek40 (Jul 8, 2005)

Whatever else happens....STOP using the crapola ricer Forge hybrid DV.....our engine management systems are designed to be a closed loop. Your ECU is looking for the proper pressure dump back into the intake when the throttle closes....if it doesn't see it all kinds of fun things can happen (including check engine lights) 
Invest in an APR R1 DV if you want the best.....


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## stockstatus (Jun 4, 2012)

Will plugging the horn with the supplied fitting work as well? 

I have the horn on now and it seems to be doing good. 

Regardless i will be switching it up after i recoup from the financial blow 

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## stockstatus (Jun 4, 2012)

*Here we go again.....*

All the issues seem to be back FUUUU!!!!!

So I decided I would adhere to the warnings that the forge DV spltr was garbage as it started to get nerve racking anyway. 

Stuck the stock one back on

Headed out from class last night and epc was on I stopped and had it read at a o'reilly on the way home and checked it p1297 turbo to throttle body pressure loss. 

also a throttle position code i will list that and the freeze frame data on here as soon as i get back to the car. (implausable) is what it said i believe what does this mean I have had both the TB and pedal assembly replaced. 

and I have tested the stock DV and the forge both operate properly and hold vac. and I made sure that the fittings were tightened all the way as well.


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## stockstatus (Jun 4, 2012)

I scoped the maf and ect and tps with a modis but the dam thing decided to run fine while i was checking it out i even took it out on a closed road and ran it to the floor and i couldnt recreate the issue 

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## stockstatus (Jun 4, 2012)

*uneducated thinking*

I have been replaying the symptoms and the past issues in my head during lectures to try and come up with some bs reason that this would be happening again so i can sleep tonight. 

This is what i came up with (if your having similar issues this is a brainstorm not a diagnosis) 

(recap)
Issues started, took it in to a local shop. shop found pcv system to be faulty (not sure what was faulty that will come into play later) and throttle pedal to have issues. shop replaced throttle pedal and pcv. codes cleared and readiness was set. 

I pick up the car and issue comes back a few days later

Take it back to the shop and they say it must be the throttle body its not opening and closing all the way so its reading a pressure loss and implausable signals. I ok the replacement of TB and again issues are gone, and readiness codes are set. 

I again pick up the car and again a few days this time weeks, the issue is back, 

Im driving to class EPC and CEL illuminate O'reilley scan shows the same 2 codes as the last 2 times p1131 (Throttle body) and p1297 (Boost leak Turbo to tb)

I spent the rest of the day on all data and came to this conclusion,
My pcv system may have been sucking oil (minute amounts but over time) this eventually made its way through the charge system and began to foul the MAP. I am yet to check the MAP, tom. I will be cleaning it, its obviously within spec, but maybe its coated enough to throw a wild reading every once and a while and this makes the pcm think that i am loosing pressure, which then commands the TB to adjust its idling conditions. And that some how triggers an implausible signal at the TB while driving. (I have never seen it, but i hear MAP sensors can foul.) 

I seriously doubt this but it made since on a napkin. and its what i'm going with until i can prove otherwise. 

Again If your reading this with similar issues it hasn't been proven.


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## stockstatus (Jun 4, 2012)

Light just popped on epc pulled over cleared drove less than a mile and epc was back accompanied by a cel. Pulled back off cleared and made it home no issues. Wtf.

still havent checked the map im also noticing a 1"hg or less chatter at idle with or without ac any ideas??? 

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## stockstatus (Jun 4, 2012)

Just took it by the same shop and they plugged it in she walked out and shook her head "this car does not like you" apparently there are a few codes that are new along with the old ones. Though the tb was just replaced they suspect it to bad (its not reading angles). 

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## Rockerchick (May 10, 2005)

What codes are being thrown? Where in NC are you?


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## stockstatus (Jun 4, 2012)

Salisbury the shop is here in town they didnt give me a list of the codes this time i was in a bit of a hurry but generics that i got off my scanner were the throttlebody implausible and the standard loss of pressure between turbo and throttle valve. 

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## stockstatus (Jun 4, 2012)

P1297 P1545 are the generic obd2 codes 

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## Rockerchick (May 10, 2005)

I went to Catawba  Don't know of any VW shops in Salisbury though. 

Eurowise in Charlotte and Everything Euro in Winston are good places though. They will probably be able to help you out better. 

Here is some info on your codes. This is a great site to reference codes with. I check it all the time for codes: 

http://wiki.ross-tech.com/wiki/index.php/17705/P1297/004759
http://wiki.ross-tech.com/wiki/index.php/17953/P1545/005445


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## stockstatus (Jun 4, 2012)

I have heard good things about eurowise if need be after this i will be going there. 
What year were you at catawba? I live 10 min from campus 

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## Rockerchick (May 10, 2005)

I've not been to Eurowise or Everything Euro, but heard good things about both. Both places are on the local VW forum (ncdubs.org if you're interested in signing up) and have been for some time. 

I graduated Catawba in '09. Great little school.


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## stockstatus (Jun 4, 2012)

Taking it in on monday
for an update it idled like garbage this morning after warming up then i got to work and tapped the throttle body a few times and pushed on the connector. Now the idle is fine im just in soft limp. 
Cant wait till monday. 

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## icarusart (Mar 25, 2012)

*Tuning*

My 1.8t was very sensitive to aftermarket add-ons. I'm guessing that the car I had was tuned to run on certain inputs and outputs in the engine management system. I went with a very basic aftermarket replacement DV, only difference from stock was the metal housing. Perhaps you need an ecu upgrade if you are using serious aftermarket addons.


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## stockstatus (Jun 4, 2012)

IDK Ill put the Forge DV back on if it does fine after this visit to the shop. 

This thing is driving me crazy though, its trying to run fine today but I can tell its using a strategy of some sort. When I got in it this morning it idled up to 1300 and stayed there for a bit the vac was doing a dance and it just hung there for about 5 min while I finished my coffee.

Then it idled down to right around 800 and it was very sputtery if that's a word lol on the way to work. No limp mode or CEL or even soft limp. However it would make a thump noise from the exhaust at stops just idling didnt seem to affect the idle just like someone was kicking the underside of the vehicle 

And this afternoon after work it idled at a little over 1k and slowly worked its way down in steps. I have got to get my own VAGCOM cable. 

Also getting pretty shatty fuel mileage. like less than 25 mpg


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## icarusart (Mar 25, 2012)

*Idle*

I'm not 100% sure on this but, it does sound like a vacume issue, maybe oxygen sensor or MAF sensor issue, perhaps a cam/valve issue (last resort). Oh and I wouldn't worry too much about the thumping issue, when my 1.8t was at cold start, the exhaust would thump a little during warm up. I'm guessing the thump is just a temperature change and expansion of the exhaust system. 

Good luck:wave:


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## stockstatus (Jun 4, 2012)

When she was running good i asked an instructor about the thump and he said he has gotten the same complaint from numerous customers the last few years of his career and he came to the conclusion that the pcm is just leaning it out for some reason at lights to lower emissions.

I'm dropping it off at 11am tom. after work this is the last chance before i send it to either the dealer or eurowise. Tonight it would not crank without giving it throttle and then when it did it idled 400 to 1200 then once it stopped bouncing a cel and epc light came on. Think i may have set a speed record with epc on 65ish haha. I pulled over after about 10 miles and cycled the engine off and was able to drive home normal. 

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## stockstatus (Jun 4, 2012)

Dropped it off at 11 with the shop and they called at 4 so ima pick it up tonight. Really hope its fixed 

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## stockstatus (Jun 4, 2012)

No good just tried to pick it up and epc light came on as i turned out. So i just pulled back in and parked it i wasnt limping it home tonight. ill call them in the am and see whats next hope to have it at the dealership or eurowise by the weeks end 

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## icarusart (Mar 25, 2012)

*Stuff*

Hi, I just read that you keep having the same codes. First I don't think that a P1131 SAE code even exists for this set-up. Second codes P1297 and P1545 is more of the same that I mentioned before. P1297 is an turbo exhaust side vac issue. And the P1545, your throttle body doesn't know what it's doing or where it is. First check all the turbo system pipes/hoses/sensors for leaks. Second determine why the throttle body can't find itself. It can be that the sensor or wires are messed up. Have someone that knows about VW/ European cars look at it if you can't figure it out. If there is a Camaro parked at the repair shop, I would look somewhere else. And lastly when you do get the car running perfectly, do not mess with the MAF sensor or throttle body. These sensors are super sensitive and even cleaning them can destroy their functionality. :thumbup:


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## stockstatus (Jun 4, 2012)

The shop its at has a parking lot full of Mercedes BMW's and VW
i really think its a wiring/ electrical issue 2 tb and a pedal have done nothing for the throttle codes lol 
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## icarusart (Mar 25, 2012)

*Repair*

Good to hear. The 1.8t is a good engine. Make sure you do the timing belt and water pump as required if it's not been replace already, it's a critical maintenance.


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## stockstatus (Jun 4, 2012)

Yeah i love the car, and timing was done at 90k its now at 120k

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## stockstatus (Jun 4, 2012)

Ok so I called the shop, its ready again they said they replaced the tb this time... when I asked what they did yesterday they said that it had to be re adapted to confirm a faulty tb before warranting it out. 
Sounds legit I suppose. So tonight I will try again hopefully I will get many epc free miles out of it. Record as of now is 937 miles w/o epc. 

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## stockstatus (Jun 4, 2012)

Picked it up all seems well so far I think lol I suspect the LTFT to be learning new parameters bc coming to a stop drops the idle quite a bit and it became less apparent as i drove home got a vid i may try to upload later. 

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## stockstatus (Jun 4, 2012)

I retract my previous post... epc light came on i was driving with AC on up a small hill vac was at 12 or so when i felt it, a small jerk vac gauge zeroed out and returned to 17 and epc came on 
Bahh
Pulled over let it clear and it was back in less than 2 miles.

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## icarusart (Mar 25, 2012)

*EPC*

AHhhhhh, Dude, you have to pull some codes off of this ECM and see why it's giving you the EPC...... Best of all you will know why better then the shop as to why the EPC light comes on...... Change to the stock "WORKING" DV valve, none plastic. And work backwards from there.... Better yet check to see if you're o2 sensors are giving the correct fuel adjustment curves to the ECM.... Also, if you do any serious performance mods to the fuel/air/evap system without deleting the stock programing, expect to live with CEL/EPC lights .... Lastly, you can see yourself where the vac leak is..... Have you changed the entire PCV system housing thing that sits somewhere on top of the engine?? could be the problem that simple... Have you checked all turbo hoses for leaks???? I bet the shop wasn't looking for those... Spray some start fluid in key areas and see if it makes a differance in idle,, (engine cold). Hope this helps in your effort... and good to see the timing is done 
AJ

If all else fails, Hanz at VW knows the answer...Don't offend him...


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## icarusart (Mar 25, 2012)

*ECP light*

Also check around for info about the EPC light.....And make sure you have the updated revised and newly revised coil packs for the 1.8 AWD. 


Later
AJ:snowcool:


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## stockstatus (Jun 4, 2012)

Thanks guys im sure its something extremely simple at this point. Im just gonna hold out till monday and take it to vw. Taking my car places kinda makes me feel lame but i have zero time to even wash it at this point and ima see what they can do on a stage 1+ if everything checks out 

I will update and let u all know what it actually was so we can all laugh while i face palm the mess outa myself 

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## stockstatus (Jun 4, 2012)

So today i put the forge dv in full recirculation mode and installed it and drove to the lake. On the way at some point the cel went off.

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## icarusart (Mar 25, 2012)

*Valve*

I see you are making some progress. The stock ECM programing will run your system at an optimum state if all the parameters are in sync. If you throw those numbers off by aggressive mods without adjusting for them, you will get all the warning lights and all limp modes.... I ran my 1.8t with just a standard aftermarket DV, intake, and exhaust. And it was happy for thousands of miles..... If your brave to upgrade, then I say go for it.....IF CEL is the issued go stock......Happy tuning....


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## stockstatus (Jun 4, 2012)

I got a call from the dealer today they said it was tough to chase down but they are confident that the dv was the issue i told them the stock one was in the back if they want to try it and made them aware of the issues being present even with the stock dv. He said they would keep looking. i feel good about these guys hope they get it right for me.



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## stockstatus (Jun 4, 2012)

Called the dealer today for an update and they said the intake hose was leaking not sure if its the turbo inlet hose or not, counter guy wasnt sure. But part will be on friday. Woohoo

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## stockstatus (Jun 4, 2012)

soo apparently the diagnostics level of the last shop is DEE DEE DEE because these guys at VW found a leaking intake hose. I'm assuming the Inlet pipe. They said after i dismissed the DV that they went straight to it. part will be in friday morning and I can pick it up that afternoon. I dont wanna jinx it but im pretty excited to have it running right.


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## Rockerchick (May 10, 2005)

Yeah I wouldn't go to that other shop again.


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## stockstatus (Jun 4, 2012)

Ill be stopping by later next week to do some hefty s**t talkin

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## stockstatus (Jun 4, 2012)

Dayum.... dealer called today when the tech went to install the part they had ordered the wrong one and the new one won't be here til Wednesday good news is the part was 200 more than they originally said and i am paying for the cheaper part.

I asked which hose and they said turbo bypass?? 

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## stockstatus (Jun 4, 2012)

Picked up from the dealer tonight and all seems well i will update after i drive a little more 

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## stockstatus (Jun 4, 2012)

So it ran well all the way to school but the vac gauge still kinda rattles at 20hg at idle and 18hg with idle and ac wonder if my leaky oil fill cap is the culprit of this. 

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