General Misfire / Cyl1Misfire / Cyl 3 MisFire - NEED HELP

[SoMdAudiA4]

Need some help guys.

B8 A4, 30k miles, GIAC Stg1 tune (thats it)....started misfiring and stumbling all over itself last week...wasn't to bad and thought it was simply a case of bad gas. As the week went on, it got so bad the car couldn't get out of its own way....CEL comes on and from 0-45mph it was like trying to move a tank.

I ran the CEL's and they were the three mentioned in the subject. I ordered the R8 Coils and replaced those this evening when they came in. Started it up and the problem still exists. Engine is shaking so bad it looks like it wants to jump out from under the hood. Also noticed a puff of smoke and when I walked to the rear of the car I noticed it shot oil onto the back garage wall (1' away).

I'm no mechanic and at this point don't know what to do.

Thanks in advance guys.

[van462]

It could be one of several things but going off of just having codes 300,301 and 303 without other codes I think you may have a stuck fuel injector. It will normally be associated possible exhaust smoke that will smell very fuel laden (rich) usually makes your eyes water. The "oil" that shot out of the exhaust may be a mixture of fuel, water vapor and carbon. How did you get the codes (what equipment do you have)? If its VCDS or Carista I can give you other settings to look up such as fuel trims, O2 equivilenace/lambda. Fuel rail pressure (sensor value)and then shut off motor and check to see if it bleeds.
You may try unplugging the MAF and see if the idle smooths out.- Not as likely a suspect as the MAF isn't used much at idle but more once throttle is applied. Usually triggers a code as well

Are the spark plugs light brown on the electrodes are black/wet (heavy fuel smell)

Things I have ruled out based on having solely the 3 codes with no others.

Timing/ tensioner failure- Still possible but if its running that poorly, it usually has 0016 code as well.
Massive intake leak/PCV- usually comes with a code for running lean. If its so lean that its misfiring the ECU usually detects it. You could try unplugging the hose going from the intake manifold to the PCV and put your thumb over the intake manifold hole. If the idle returns smooth then you have a PCV issue and likely a failing rear or front main seal.

[SoMdAudiA4]

It could be one of several things but going off of just having codes 300,301 and 303 without other codes I think you may have a stuck fuel injector. It will normally be associated possible exhaust smoke that will smell very fuel laden (rich) usually makes your eyes water. The "oil" that shot out of the exhaust may be a mixture of fuel, water vapor and carbon. How did you get the codes (what equipment do you have)? If its VCDS or Carista I can give you other settings to look up such as fuel trims, O2 equivilenace/lambda. Fuel rail pressure (sensor value)and then shut off motor and check to see if it bleeds.
You may try unplugging the MAF and see if the idle smooths out.- Not as likely a suspect as the MAF isn't used much at idle but more once throttle is applied. Usually triggers a code as well

Are the spark plugs light brown on the electrodes are black/wet (heavy fuel smell)

Things I have ruled out based on having solely the 3 codes with no others.

Timing/ tensioner failure- Still possible but if its running that poorly, it usually has 0016 code as well.
Massive intake leak/PCV- usually comes with a code for running lean. If its so lean that its misfiring the ECU usually detects it. You could try unplugging the hose going from the intake manifold to the PCV and put your thumb over the intake manifold hole. If the idle returns smooth then you have a PCV issue and likely a failing rear or front main seal.

I checked with the standard OBDII Scan tool that you borrow from Advance Auto Parts.

You may be right about the water/fuel/carbon/etc blow out from the exhaust and that its not oil. However, why would it now blow out so much and why now with the puff of smoke (believe it was white smoke not black)

If stuck fuel injector- whats the fix or how to test?

[van462]

White smoke is what others with injector issues have seen. There is no good way to test. Injectors have been another problem area and Audi did extend the warranty on them. I do not remember the exact number a search n here will likely bring up some decent threads. About the only troubleshooting you can do is pull the plugs and see which one looks wet and fouled and likely that is your cylinder. The fuel rail runs at pressures exceeding 1200 psi so a fuel pressure tester looking for leak down doesn't work. A VCDS cable or carista can read the sensors reading and you can see it bleed down on engine shutoff. Also looking for fuel trims where the ECU senses the rich condition and is trying to go lean but can't correct the condition cia the O2 sensor reading. The fix is replace the injector, cleaner likely won't help. A new injector will also need a new seal and there is an installation tool for the seal. Some have put it on without the tool.
Look over this DIY for cleaning the intake valves, not a bad idea while you are there.
http://www.audizine.com/forum/showth...?highlight=diy

[SoMdAudiA4]

White smoke is what others with injector issues have seen. There is no good way to test. Injectors have been another problem area and Audi did extend the warranty on them. I do not remember the exact number a search n here will likely bring up some decent threads. About the only troubleshooting you can do is pull the plugs and see which one looks wet and fouled and likely that is your cylinder. The fuel rail runs at pressures exceeding 1200 psi so a fuel pressure tester looking for leak down doesn't work. A VCDS cable or carista can read the sensors reading and you can see it bleed down on engine shutoff. Also looking for fuel trims where the ECU senses the rich condition and is trying to go lean but can't correct the condition cia the O2 sensor reading. The fix is replace the injector, cleaner likely won't help. A new injector will also need a new seal and there is an installation tool for the seal. Some have put it on without the tool.
Look over this DIY for cleaning the intake valves, not a bad idea while you are there.
http://www.audizine.com/forum/showth...?highlight=diy

Thanks. So tomorrow I'll pull the engine cover and coil packs out again. I'll check cyl 1 and 3 plugs first since those are the two cylinders identified in the CEL codes, i'll then compare those to cyl2 and 4 for comparison. Audi replaced the plugs maybe 9k miles ago....not that it matters. If none are wet or appear fouled out...then who knows.

Side note -I called the service writer at my local dealership. They consider themselves "tune friendly" and offered to send a tow truck since I'm under the Certified Pre Owned Warranty. I then explained that the car just doesn't seem driveable and that I'd be concerned they would identify the car is tuned as part of their diagnostic procedures and then Audi would stop all work and I'd be up shit's creek...and to add to then have to get the car out of there still in pretty bad shape..she has the CEL codes and is going to check with the shop foreman to see if they have to use the specific diagnostic tool that would identify the tune and flag the car, if not the tow truck will come get it and its their issue to fix..if so, then I have to figure out how to remove the tune or continue trying to identify and fix the issue myself :(

[SoMdAudiA4]

So I didn't get a chance to check the plugs because Audi had the tow truck in my driveway before I got home (CPO warranty coverage). I did however test the PCV valve by taking the oil cap off while the car was started. There was no vacuum pressure, but pressure pushing the cap away from the motor, clouds of burnt oil very very quickly filled my 3 car garage. I shut her down, put the cap back on and pushed the car out to the tow truck. Lots of click and clacking and rattling the 45 seconds it was running...no smoke from the exhaust this time though.

We'll see what the dealer says tomorrow...my biggest concern is Audi copping out and pointing to the tune as the issue, even when it may not be related...

[DoItAllGarage]

Any updates, tell them to do a leak down test. This will rule out and internal engine problems and should only bill an hour or less for the test.

[SoMdAudiA4]

Sorry guys for the delayed update...

So they did a leak down test and determined cyl's 1, 2, & 4 were good, but 0 compression in cyl3. They tried multiple different ways to get the compression back, all of the failed. Eventually Audi approved them to drop the oil pan to look for shavings, etc....well they found an oil ring in the pan. Audi shipped out a new long block next day and now I've got the car back with a new motor.

Service Manager said in his 30 years of both Audi mechanic and then service writer (now manager) he only saw this one other time...