1.8t AWP weird "lagging / surge / stutter" boost / throttle feel ?

[AEGTI3913]

Wondering if anyone has any experience with 1.8t boost fluctuation, and might be able to point me in a direction for fixing the symptom. Any advice is much appreciated. The problem as I can best describe:

Car: 2003 Anniv GTI - AWP - bought new - ALWAYS 93 octane, ALWAYS synthetic (not that I think that's related).

The symptom first appeared maybe a year or so ago and would only appear rarely (once a month maybe), and usually only when the car was warming up and driving out first thing of the day. When I would pull out in 1st gear, giving it a little throttle, when I would let off the pedal a hair I would feel an ABRUPT drop in deceleration just for a second. Like the boost disappeared for a moment. Where the car normally just smoothly backs off / slows down.

It happened so rarely and was so minor, I didn't pay it much mind.

The other day I decided to flash with car with a 93 APR map (finally, at 95k. Don't ask )

Now, that same symptom described above, can be felt more regularly, and can almost be created upon request: If I'm in say 3rd gear at maybe 2000 to 2500 rpm, then put the pedal down maybe 3/4 to build some decent boost, when I let off a hair, but hold the pedal and remain in gear, I can feel a weird stutter or abrupt momentary drop in what I'm perceiving as boost pressure. In other words, it seems to be the same issue I was previously only having on rare cold/startup situations.
Maybe the higher boost and or increased ignition timing is bringing the issue more to light?

The DV was replaced a while ago with the better 228 TT DV, and is holding vacuum fine.

- Someone suggested maybe it's misfires, and maybe start by changing the plugs.

- Anyone have any insights, or has seem this issue in these motors before?

Many thanks in advance!

[thefrese]

Sounds like a boost leak to me, there's a guide for finding them on the 1.8t forums.

[Sickvwguy]

could be the N75. I had a surging issue and replaced it and boom no more surge. Do you have a boost gauge?

[805 GTI]

i bought my 02 gti about a month ago. that used to happen but aggressively.... i would give it gas and it seemed like the car would die for a fraction of a second when the boost would start kicking in then it would start picking up again..... i kept driving it like that always on 91 and it went away a considerable amount.... now i could only feel it a little bit and and not as frequent.
oh yea i also seafoamed it and it helped out too

[AEGTI3913]

Thanks for the quick replies guys.

- I don't have a boost gauge in the car.

- I'll do a search for boost leak

- seafoam?!

[Alcrerion]

http://www.seafoamsales.com/how-to-u...treatment.html

[AEGTI3913]

thanks.

805: Did you spray a can into the throttle body, dump some into the gas tank, or something else? Any idea which product you used?
TIA.

[JustinGora]

Call the dealership and give them your VIN. Ask to check if your car got the coil packs changed during the recall in 07. I bought my car last year and had the same problem. They will replace it for free

[AEGTI3913]

Thanks for the coils suggestion. I should have mentioned that new coils went in maybe 6 months ago.

Anytime I have a coil issue, it was serious. Like the car was literally running on 3 cylinders and you knew something was really not working right.

The issue I'm experiencing now is MUCH more subtle. I think the guys who are recommending a boost leak or maybe N75 issue may be on to something. I'll update.

[MrSavvy]

could be the N75. I had a surging issue and replaced it and boom no more surge. Do you have a boost gauge?

I don't have a tune but I do have these sputtering and odd boost issues. I replaced my MAF last week, and it helped reduce the problem, but it definitely still plagues my GTI (1.8t AWP). I'll be replacing the n75 on mine as well.
I'm hoping that's all it is.

[Sickvwguy]

Just replace it with a stock N75 and you should be golden.. No tune yet for me either..I don't think anyways lol it holds 12psi. I bought the car used and have no idea if it has any software on it..I can tell you the short ram intake, 2.5" turbo back,the high flow exhaust manifold, and FMIC make a pretty significant change in power. Can't wait for frankenturbo


Sent from my throne using Crapatalk

[subisan]

0. boost leak
1. spark plugs
2. coil packs
3. O2 sensor [bank 1]



I had the same symptoms for quite some time and it ended up being the bank 1 O2 sensor, AFTER I had replaced all of the above.

[AEGTI3913]

Dude.. very nice timelapse video. What do you charge per hour to do work that fast?

I'll add the O2 sensor to the list of possibilities. Thank you.

Any chance you can identify the part for me, or where it's located? Couldn't find anything on search.

[subisan]

Dude.. very nice timelapse video. What do you charge per hour to do work that fast?

I'll add the O2 sensor to the list of possibilities. Thank you.

Any chance you can identify the part for me, or where it's located? Couldn't find anything on search.

Thanks dude, I charge double for work that fast.

It's in a sneaky spot on top of the downpipe just before the catalytic converter. You can get to it from underneath the car pretty easily. Check this link out: http://euroturbo.net/guide-on-downpi...t-20v-engines/

[AEGTI3913]

So I'm guessing in this image:
http://euroturbo.net/wp-content/uplo..._oem_stock.jpg

The two holes showing just before and after the cat are for the O2 sensors? The one closer to the turbo is bank 1, and the one closer to the exhaust is bank 2?

[subisan]

So I'm guessing in this image:
http://euroturbo.net/wp-content/uplo..._oem_stock.jpg

The two holes showing just before and after the cat are for the O2 sensors? The one closer to the turbo is bank 1, and the one closer to the exhaust is bank 2?

Exactly!

[Fastvolks]

I would definitely check the plugs I had a similar issue and two of my plugs were not gapped properly which can happen over time with old plugs. Also if you recently got flashed I would replace those plugs for sure and make sure they are gapped for your setup.

[Dauz]

I sold my 1.8T and picked up a 24v for this very same reason. Acceleration is now so gd smoooooooth.

[AEGTI3913]

Subisan: Thank you!

Fastvolks: It's on my list for sure. Short money in my book for something I should do even if it's not related to the issue. Any suggestions on how to find the right gaps for my car? I've got a '03 Aniv. GTI (1.8t AWP) with an APR 93 oct flash.

Dauz: Thanks for the suggestion. I'm a bit attached to this one and like the lighter motor for handling on (and off) the track.

[Fastvolks]

Fastvolks: It's on my list for sure. Short money in my book for something I should do even if it's not related to the issue. Any suggestions on how to find the right gaps for my car? I've got a '03 Aniv. GTI (1.8t AWP) with an APR 93 oct flash.

.028

[AEGTI3913]

Thanks Fastvolks. I did some searching and looks like stock plugs are aok (as opposed to NGKs) if the car is otherwise stock. So I'll be grabbing some stock plugs and gapping to .028 Thanks

[Dauz]

Dauz: Thanks for the suggestion. I'm a bit attached to this one and like the lighter motor for handling on (and off) the track.

No worries. I do have to let you know that I've fought this battle on many fronts and lost. Pretty much did everything that was suggested and then some and still couldn't be rid of the stutter 100%. So I thought it'd be best to pull the plug before I lose any more sleep over it. I did have an '05 GTI with the AWP.

[corradoproblem]

I will say that the coils can cause this, and did for me, with no cel and only under load/boost. But I will also say my own car has has a long history with this type of issue in varying severities over the years. It could be a boost leak yes, but is it boosting full when WOT? Do you have a boost gauge? Is the vacuum good? My issues are with part throttle and most would point you to the N75 if that's the case.

Another time I had issues like this it was the start of the exhaust manifold and turbo housing cracking. It started as fluctuations in boost and eventually turned into a total lack of boost.

Fixing all of of that stuff has made my car run quite well, however, I still have a lack of smoothness with part throttle and I am convinced it is a byproduct of the chip tune.

[Slimjimmn]

http://www.ecstuning.com/ES7679/

done

[805 GTI]

thanks.

805: Did you spray a can into the throttle body, dump some into the gas tank, or something else? Any idea which product you used?
TIA.

yea i used seafoam.... i put half in the tank and half of it through the vacuum line lgoing into the intake manifold...... you could also put a third into the tank a third into the crankcase and a third through the vacuum line, but make sure to change your oil afterwards if ur going to out some into the oil...... it helped out A LOT!!! me nd my brother did it to his cobra and it made a huuuuge difference..... i also cleaned the maf sensor with maf sensor cleaner
huge improvement than when i first bought it

[pl4life52]

I also have this issue I bought the car a few weeks ago it has a revo stage1 tune and when im on the gas like OP said 3/4 or fully down and i ease off of it it feels like a strong drop and also today i was pulling out and i stepped on it and the car boosted and then i heard a pop sound and no boost for about a second then it kicked right back in... any ideas? should i do my plugs as well if so anyone know where i can find the right gap for this tune.

Thanks and OP keep us posted with updates

[_Brenon_]

Call the dealership and give them your VIN. Ask to check if your car got the coil packs changed during the recall in 07. I bought my car last year and had the same problem. They will replace it for free

So glad I opened this thread. I just called them and checked, the recall was still open so I get my coil packs replaced Monday at 2. Fnck yea!

[805 GTI]

theres also a recall for a bunch of other things.... you should as them about it
it's for like brake lamp switches and other things

[AEGTI3913]

Thanks for all the posts guys.

pl4life52: Sounds very similar to my symptoms, just no popping noises for me.

I still haven't dug into making changes yet. I'm not sure if I'm going to have the shop that did the APR tune last week put the car back to stock map and see if this eliminates the issue. We're going to discuss all these other possibilities too and figure out best way to move forward. There is a window of timing to be able to get a refund on the tune if I want to go that route. I'd like to keep it, but not if it's going to make the motor run funny with an un-fixable issue.

COILS: I looked at my records, and looks like I put in 4 new coils Sept. of 2011 @ about 10,000 mi ago, so I doubt its the coils.

PLUGS: When the coils went in, we also put in 4 new plugs, although they are probably gapped to stock tune, not .028. Sounds like the gap COULD be a factor, but more likely one of the other items.

D/V: Looks like the car already has the newer TT D/V. I'm told the original D/V's for this car were crap to begin with. I'm not sure when the new one went in, but it's probably not the D/V.

N75: Haven't looked into this yet - sounds like a def. possibility - I'm guessing there is a way to stick diagnostic on and see if it's behaving?

O2 sensor (bank1-before cat): Seems like this could also be a possibility, although I don't know enough about what it's readings do to engine management to confirm this suggestion/possibility.

VAC leaks: Also a possibility I guess from the sounds of what people are saying

Boost leak: Also a possibility I guess from the sounds of what people are saying

I should be the shop that did the tune on Tues and might have new info to post after that trip.

Can a diagnostics check point out N75, O2, VAC, Boost numbers that don't match / look right? Before I go replacing a bunch of parts on guesses...

[Slimjimmn]

Uh... Did you check your coil harness buddy...
The link I provided to ecs shows pics of a bad harness

[AEGTI3913]

Hey Slim.

I guess I didn't understand the link, sorry. Sounds like you're suggesting my wiring to my coils may be old/cracked/worn/dead/whatever, and if so, should be replaced. ? Makes sense. The car is almost 10yrs old and lived in New England it's whole life, so with age and temp changes, sounds reasonable to me.

The only thing that I wonder about with anything related to the coils is that when I've had coil issues the motor is just screwed. Like only firing on 3 cylinders. So it's black and white. With this issue, it's subtle and only happens when I let off heavy throttle and hold it at partial throttle. It's momentary a momentary "lag" but smooths out after a second. Seems like if my coils weren't firing (even sometimes) I'd have bigger problems. ?

[walker.2003]

Hey, i have this issue and i will get a video of it and post it online tomorrow night. When this happens im driving slowly and in first gear, it will all of a sudden lose power for a split second and then kick back in. when looking at the boost guage it will be at 15vaccum or wat ever and then when it loses power the vaccum will go to 0 as if the car was under acceleration.

[Slimjimmn]

if you watch MVB with a vag com and the car misfires, the ecu pulls timing and boost. If its a dead mis it will drop off like that for safety reasons (dont want to boost with a misfire).

I have 136k on my harness and its cracked to heck. I attempted a year ago to retape over the cracked wires and it seemed to work for a while, but I think more wires have cracked and its causing this.

The coil harness has 4 wires to it- power, ground, signal wire, return wire for signal.
If any of those cross short it will cause misfires. Especially on wet foggy mornings!!

I just bought a harness today, $63 at my dealer w/ discount. $78 list.
Putting in tomorrow.

also, a pre-turbo exhaust leak or weak/failing fuel pump will do this.

[pl4life52]

thats what mine does just drops and kicks right back in, how would i know if its the D/V for some reason i think its that but im not sure. Would a lot of turbo lag hesitation be because of the D/v

[Slimjimmn]

thats what mine does just drops and kicks right back in, how would i know if its the D/V for some reason i think its that but im not sure. Would a lot of turbo lag hesitation be because of the D/v

sounds like fuel pump dying.
It takes 2 seconds to check your diverter valve. unbolt it from the TIP, push up on the piston, hold your finger on the vac nipple, release piston and it should not go down. if it does, its bad


side note, did my coil harness today. I spliced the wires to the ECU and the Body harness plug since I don't like removing pins from sockets.
Worked out great! my car starts after one click its crazy. Super smooth acceleration now but I do get that drop like this in 1st gear still.
Next on the list is to replace the fuel pump since I have 138k on the clock.