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Misfires! Woo!

TheTroyness

I changed a tire once...
Location
Arkansas
Yea, I know. Another misfire thread. I'M SORRY! But I've been reading and researching and working away at this for a long time with no sign of improvement.

PROBLEM:
Misfire on Cyl. 4. It used to misfire really bad (blinking CEL and engine sputtering like traction control was kicking in) mainly under heavy load, usually WOT when I punch it going on the on-ramp getting on the interstate. After installing a catch can and replacing the coils, it doesn't do it noticeably under WOT, but when I start my car, it usually causes my CEL to flash for a few seconds. Sometimes it flashes longer. One time it didn't stop flashing and I could hear my engine misfire. Sounded like one cylinder just wasn't firing. I shut off my engine and tried again and it didn't have any issues at all. Problems seem to be worse when it's cold out.

BACKGROUND:
I bought my 2006 MKV GTI a little over a year ago (used, obviously) from a used car dealer. I've had some form of check engine light since buying the car. Before I got a VAGcom, I had it scanned by the dealer a couple times and thought it was just because I was running APR turbo back exhaust almost since I bought the car. Just to make sure, though, I had them change out my coils. Because of the possibilities, and how long it took me to get a VAGcom, it's hard to say when my misfires started.

MODS:
I have APR turbo-back exhaust, APR stage II, BSH comp catch can, noise pipe delete (intake pipe was replaced with an aluminum one instead of the OEM A3 pipe), and ABDRacingwerks full CAI.

EFFORTS:
I replaced my ignition coils AFTER they had been replaced by the dealer. I swapped my cylinder 4 and cylinder 3 spark plugs. I contacted APR a few times but have never gotten a response regarding the data I sent them.
I have a set of data that I will attach (logged engine speed, intake air mass, all 4 cylinders, accel pedal pos, throttle plate angle, injection timing, boost press spec and actual, and actual rail pressure) showing some misfires. I have another set of data that I'll attach (logged engine speed, cylinder 4, rail pressures, and some other stuff) that shows misfires. In the second data set, I started logging as soon as I started my engine, let it idle for a little bit (didn't get the initial idle misfires that cause my CEL to flash like I normally do), rev'd the engine a few times, then drove around the block of my campus in first gear peaking as close to redline as I could get without fear of getting jumped on by campus cops. It's a lot of data... I checked my actual vs spec values, though, and everything seemed fine.

RESULTS:
Still misfiring on cylinder 4. Always and forever.

Below is a copy/paste of my latest code. This was an ooooold code. Had it in my car for a long time, so the count for misfires is fuggin' big. You'll know how desperate I am to get this solved when you see it...


Sunday,12,December,2010,00:25:03:35217
VCDS Version: Release 908.2
Data version: 20100326



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Address 01: Engine Labels: 06F-907-115-AXX.lbl
Control Module Part Number: 1K0 907 115 B HW: 1K0 907 115 B
Component and/or Version: 2.0l R4/4V TFSI 0040
Software Coding: 0403010A18070160
Work Shop Code: WSC 25019 444 84531
3 Faults Found:

000768 - Random/Multiple Cylinder Misfire Detected
P0300 - 008 - Implausible Signal - Intermittent - MIL ON
Freeze Frame:
Fault Status: 10101000
Fault Priority: 0
Fault Frequency: 47
Mileage: 105755 km
Time Indication: 0
Date: 2000.00.00
Time: 15:40:47

Freeze Frame:
RPM: 1177 /min
Load: 33.7 %
Speed: 0.0 km/h
Temperature: 32.0°C
Temperature: 34.0°C
Absolute Pres.: 990.0 mbar
Voltage: 14.351 V

000772 - Cylinder 4: Misfire Detected
P0304 - 008 - Implausible Signal - Intermittent - MIL ON
Freeze Frame:
Fault Status: 10101000
Fault Priority: 0
Fault Frequency: 47
Mileage: 105755 km
Time Indication: 0
Date: 2000.00.00
Time: 15:41:28

Freeze Frame:
RPM: 1075 /min
Load: 27.8 %
Speed: 0.0 km/h
Temperature: 40.0°C
Temperature: 34.0°C
Absolute Pres.: 990.0 mbar
Voltage: 14.224 V

000769 - Cylinder 1: Misfire Detected
P0301 - 001 - Upper Limit Exceeded - Intermittent
Freeze Frame:
Fault Status: 00100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 106841 km
Time Indication: 0
Date: 2000.00.00
Time: 16:03:08

Freeze Frame:
RPM: 1181 /min
Load: 45.9 %
Speed: 0.0 km/h
Temperature: 6.0°C
Temperature: 7.0°C
Absolute Pres.: 990.0 mbar
Voltage: 14.605 V


Readiness: 0000 0001
 

Attachments

TheTroyness

I changed a tire once...
Location
Arkansas
I have not changed my spark plugs because the misfire is only on cylinder 4, even after moving my cylinder 4 spark plug to cylinder 3, and vice versa. If the problem was my plugs, I would think I would either have issues on all of them or the misfire would move from 4 to 3 when I swapped them. I might still change them, though.
Are you talking about the cam follower in the fuel pump? If so, no I haven't. I would think that would cause misfires across all cylinders. Also, I tried but I have some metal lines on my fuel pump and I was having hell trying to disconnect everything and get to what I needed. I was running out of time so I decided to try again another time, after this semester of school is up and I have plenty of time.
I have no idea how to check to see if my injectors are clogged, but I considered buying some injector cleaner or fuel system cleaner or something. But I wanted to post here first for some tips and opinions.
Thank you for your prompt reply, by the way.
 

TheTroyness

I changed a tire once...
Location
Arkansas
That's exactly what I was thinking, but wanted to get some more opinions before I go out and buy a new injector and tear into my engine to replace it. Are there any ways I can prove there is something wrong with my injector prior to replacing it? Are there any fuel additives I can use that might fix the injector problem? Like if it's a dirty injector or something, what kind of things would people suggest I use to clean it out?
 

ecoterragaia

Ready to race!
Location
Richmond, VA
I had a solid CEL for misfires mostly on Cyl.1, but every once in a while on another random cylinder. Logging with VAGCOM showed that misfires only occurred within the first 10-20 seconds of a cold startup.

After changing coil packs and spark plugs, which did nothing, I got desperate and added a 7.5 oz bottle of Chevron Techron Fuel System Cleaner (not the ProGuard) to 9 gallons of fuel, and cleared the CEL/codes. Since then, I have only gotten one misfire soft code which freeze frame showed was during the time that the Techron was doing its stuff. After running this tankful through, I haven't had a soft code for a misfire since.

Pro's

* Of course, misfires gone
* Cold startup is immediate now, no more extended cranking and shaking
* Primer pump hums 1/4 as long as it did before
* Boost seems to build more quickly
* Random stumbling at idle (stoplights mainly) occurs maybe once every 10-20 seconds rather than every 1-3 seconds.
* Throttle response seems have have improved

Con's

* Oil got really black after this, I had to change it 1000 miles before schedule. Not sure if this was my imagination or what, but I'd never seen the oil that dark in the 4 years I've owned the car.
* Block 32 showed that the ECU was compensating for wide swings in A/F mixture. The worst I saw while running the Techron through was -3.3% idle and 5.9% partial. HOWEVER, after the Techron was gone and I filled up with Shell 93, it went back down to 0.0% on both partial and idle. I've checked every day since and it has still remained at 0.0%, which is better than before the treatment when it was at an acceptable -1.5% and 0.8%. I think that the Techron may have been messing with the O2 sensor, but it wasn't enough to be dangerous to the engine or anything.

I would encourage you to try it. Here's a link to what I'm talking about, I got it from Autozone for ~$8.00.

http://www.chevron.com/products/prodserv/additives/tcp.aspx
 

TheTroyness

I changed a tire once...
Location
Arkansas
I've read that you should use fuel additives (specifically Chevron with Techron) in the tank before you change your oil because the additive might leak past the seals and into the oil and contaminate/dilute it. I've also read that people use fuel additives (not necessarily Techron) in every tank, not just before an oil change, and have had no issues. Do you suggest putting Techron in right before my next oil change or to just put it in next time I fill up my tank?
If my misfire wasn't as bad as it is, I would just use it prior to an oil change just to be on the safe side, but I'd like to fix this ASAP. Almost to the point where I may consider doing an extra early oil change if need be.
 

ecoterragaia

Ready to race!
Location
Richmond, VA
I've read that you should use fuel additives (specifically Chevron with Techron) in the tank before you change your oil because the additive might leak past the seals and into the oil and contaminate/dilute it. I've also read that people use fuel additives (not necessarily Techron) in every tank, not just before an oil change, and have had no issues. Do you suggest putting Techron in right before my next oil change or to just put it in next time I fill up my tank?
If my misfire wasn't as bad as it is, I would just use it prior to an oil change just to be on the safe side, but I'd like to fix this ASAP. Almost to the point where I may consider doing an extra early oil change if need be.
I'm not an expert on fuel additives, but in this case the Techron was definately 100% more effective compared to other fuel injector cleaners I've tried. It may not fix your misfire issue, but it's worth a try in my opinion. If you've got a clogged injector, you're running the chance of burning up valves and such if you let it go for too awfully long. I can't speak for the masses, but oil is something I tend to over-do, so my recommendation is to change it after running the Techron through. I change mine every 3500 miles, and since I didn't flash my ECU there's ~12 extra oil changes I can claim.
 

nikitynick

EurotrashSD Dubber
Location
San Diego, CA
if you want to try a system cleaner I would just use seafoam before your next oil change. honestly though I dont think something like that will solve your issues. if its definitely not the spark plugs or ignition coils, it could be an injector. dont forget to check the gaps on your spark plugs as well. have you had any other codes besides the random/multiple and cylinder 4 misfires?

look into a possible boost leak as well, specifically with by the turbo and wastegate, but check the entire system. a disconnected wastegate line will cause you to overboost and misfire underload, but that doesnt explain your misfires at idle.
 
Location
Maryland
Ride
GTI
Mine was doing the cold start misfire. It's CPO so the I took it to the dealer and they replaced the injector, I'd look there for problems. Good luck.
 

Zach L

VR junkie
Location
Austin, TX
I have EXACT same problem. Cylinder 4. Completely stock. Changed plugs, changed coils, swapped coils ...never fixed. Worse when cold outside. Probably an injector. I have an extra set in the garage waiting to go in.
 

TheTroyness

I changed a tire once...
Location
Arkansas
I'm pretty sure I checked the gap (0.030") and it was fine. I've gone through a variety of codes (Intake Manifold Runner Control: Basic Setting not Completed; Sensor Reference Voltage A: Circuit: Low; Catalyst System; Bank 1: Efficiency Below Threshold; Intake Manifold Flap; Bank 1: Stuck Open; Mass Air Flow Sensor (G70): Supply Voltage; and some others) but they've all since disappeared. I think they sorted themselves out between reflashing my ECU and replacing coils and putting in a catchcan. The codes I listed in my first post are the only ones I've had in months. That log I posted actually spans from the summer till now, I'm pretty sure. I kept checking it but never cleared it.

As far as leaks and overboosting, I have a boost gauge installed that I keep an eye on, particularly when my car starts misbehaving, and I haven't noticed anything unusual. APR Stage II and it peaks just above 20, but just cruising around I can expect it at or around atmosphere.

I bought some Techron. I'm considering putting it in at my next fill up, making sure to note the appearance of my oil before I put it in, and then check it frequently to see if it changes. I'll also keep an eye on what my catchcan gunk looks like. I may or may not do a really early oil change. At this point, a premature oil change would be worth fixing this issue that has been plaguing me.

If I run some Techron through and it doesn't fix the problem, I'm going to do an oil change and replace my cylinder 4 injector. While I'm at it, I'll be cleaning out my manifold and such, most likely, as well. If I do that, I will likely document my process. I looked around for awhile and it seemed there is a lack of DIY for injector swaps or something of the sort. I'll be sure to take lots of detailed pictures and stuff with my DSLR, instead of those worthless out of focus phone pics people like to take.
 

Sudu420

Ready to race!
Location
Pittsburgh/Irwin/Greensburg
Ride
2006 gti mkv
I had the same problem on cyl #3 and it turned out to be the injector, I changed out everything trying to fix it.
same here.. all cylinders were misfiring till i used techron fuel system cleaner then only cyl 3 remained. ended up swaping out that injector and havent had an issue since.
Try moving just the coil from one to the other. Looks like you may be rippin off that intake mani pretty soon!

edit-btw check the 'tex for an s3 injector install DIY.. that seems to be the best DIY for intake mani and injector swaps.
 

TheTroyness

I changed a tire once...
Location
Arkansas
Yea, it looks like I'm going to be ripping off the mani, alright. I don't think it will be completely necessary, but I want to do it anyways. Would be fun and give me an opportunity to see just how nasty things are inside. God only knows what the person before me put in the car...
I looked for the DIY and couldn't find anything. I'm sure I can figure it out, my only concern is what required tools am I going to encounter while trying to take off the mani and remove an injector? I'm not going to buy the fuggin' crazy expensive injector tool kit. That's madness! Also, where can I buy an intake manifold gasket? I couldn't find one on ECS.
On a cosmetic side-note, for a while I've been playing with the idea of shaving off those fins that are all over my intake manifold. They don't look like they serve any structural purpose, and I seriously doubt the contribute enough to cooling to make a difference. Also, if I shave the fins off, I might paint or coat the mani in something. Whaddaya guys think?

EDIT: I found the gasket on ECS, I just had to search for a part number I found in an engine schematic.
http://www.ecstuning.com/Volkswagen-Golf_V--2.0T/Search/06f129717/ES1895512/
Correct gasket, right? Now I'm just down to figure out what tools I will need...
 
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