Need help with a rich running turbo car

[threeputtpar]

The car: 2003 Audi A6 2.7l twin turbo, auto transmission

The problem: I just recently had the car tuned to increase the boost and fueling, resulting in adding ~60hp and ~80lb/ft of torque. I also upgraded the diverter valves to accomodate the increased intake pressures so they don't dump the boost when they shouldn't. Now what is happening is I am getting 4 CELs for a rich condition at both idle and off idle, and on both banks. My tuner suggested I test for vacuum leaks.

I've pressure tested the intake system and found no leaks. I've cleaned the MAF, and I've changed out the coolant temp sensor both with no change. When I reset the CELs, the car performs great for about 20 miles and then the LTFTs get past their threshold and the car seems to revert back to stock boost levels. It never goes into limp mode and I can still drive it fine as is. From my research, rich at idle is typically a vacuum leak, and rich off idle is typically a MAF going bad. I haven't yet logged the actual numbers from the MAF, but will try to do that this week. The odd part is that right before I took the ECU out, I was running slightly lean at both idle and off idle so it would be strange timing to have the MAF fail at that exact time.

Anyone have any advice or similar experiences, I'd love to hear what you did to address these codes.

 

[Clevy]

Did you have it dyno tuned. This sounds like poor tuning to me. Or you have just exceeded the abilities of the stock parts.
Search the web for a tuner experienced with your vehicle. Pick their brain and seen what they figure.
I think it's a tuning issue.

 

[Drew99GT]

What did you do to modify the diverter valves? Could be air getting sucked in past those valves at idle and right off idle. Are they vented to atmosphere or back into the intake?

 

[threeputtpar]

No dyno, just a proven off-the-shelf base tune to increase boost. The guy doing it worked for a well know company in the Audi community and has rave reviews on Quattroworld.

Most of the guys on Quattroworld are pointing at the tune also, but I want to rule out all other possibilities before sending it back and having my car down another week.

 

[threeputtpar]

I upgraded them to the OE ones from a 225hp Audi TT, which is standard practice when going stage 1 on an Audi 2.7t. They are vented back into the intake.

During the pressure testing, it did have one clamp that was a bit loose. I tightened it and the hissing went away, but no change to the rich condition.

 

[rjundi]

Originally Posted By: threeputtpar
No dyno, just a proven off-the-shelf base tune to increase boost. The guy doing it worked for a well know company in the Audi community and has rave reviews on Quattroworld.

Most of the guys on Quattroworld are pointing at the tune also, but I want to rule out all other possibilities before sending it back and having my car down another week.


Dyno tune it or expect it to blow up soon. I think new vehicles can handle off the shelf maps but as they age and something as delicate as an Audi turbo you need a dyno tune.

My experience is from Subaru.

 

[SteveSRT8]

I would definitely blame it on the tuner. Or tune, depending.

If it's canned the site that put it out may be willing to tweak it for you. My Diablosport rep did that for me for free!

 

[randomhero439]

Get your car dyno tuned. No universal tune is gonna be perfect.

 

[threeputtpar]

Yes, he is willing to troubleshoot it for me but I have to mail the ECU back to him. I'll do that as a last resort if I don't find anything else wrong.

 

[threeputtpar]

Originally Posted By: randomhero439
Get your car dyno tuned. No universal tune is gonna be perfect.


Yes, I didn't expect this to be perfect right out of the gate. What is frustrating is the usual suspects that would cause problems after the tune have almost all checked out as good. Hopefully the MAF logging will yield some results.

 

[threeputtpar]

The 2.7t is actually a very robust engine. In the RS4, the same engine was factory tuned at 375hp and 359lb/ft of torque. I'm not worried about trashing the engine at stage 1 power levels.

 

[randomhero439]

Originally Posted By: threeputtpar
The 2.7t is actually a very robust engine. In the RS4, the same engine was factory tuned at 375hp and 359lb/ft of torque. I'm not worried about trashing the engine at stage 1 power levels.


Didnt know the RS4 motor ran rich an threw codes. Your power levels wont trash the motor, but inappropriate tuning can.

 

[threeputtpar]

Yes, I realize that. What I was commenting on was your remark about delicate Audi turbo motors, which I took to mean that the motors could not hold up to more power.

Now I see that you actually meant the tuning is the delicate part.

 

[threeputtpar]

The one thing I find strange is that the plugs are not carbon black as I would expect them to be if it was running as rich as the computer thinks it is. They are the normal light tan with no deposits. The exhaust smells normal too, not like raw fuel and the cats are not overheating.

This would lead me to believe the front O2s had gone out, but would they do so in such a quick fashion?

 

[Doog]

Originally Posted By: threeputtpar
The one thing I find strange is that the plugs are not carbon black as I would expect them to be if it was running as rich as the computer thinks it is. They are the normal light tan with no deposits. The exhaust smells normal too, not like raw fuel and the cats are not overheating.

This would lead me to believe the front O2s had gone out, but would they do so in such a quick fashion?


You may be just a small percentage off in your entire rpm range and the computer senses it and throws a code. It could be anywhere in the range and just a fraction off to do that. A decent dyno tuner will correct that. So you may not be running very rich but just over the threshold in your current tune.

 

[mechtech2]

Bring it back to your tuner and tell them what's up.
They should be able to straighten this out, unless they are incompetent.

Super rich at WOT is used to cool and get more boost, but otherwise, normal parameters should occur.

 

[A_Harman]

Put it back to stock and be happy that it runs well.
A reliable car that gives strong acceleration all the time is better than an unreliable car that gives slightly stronger acceleration once in a while, LTFT's permitting.

 

[threeputtpar]

Originally Posted By: A_Harman
Put it back to stock and be happy that it runs well.
A reliable car that gives strong acceleration all the time is better than an unreliable car that gives slightly stronger acceleration once in a while, LTFT's permitting.


This is the approach that my tuner wants to take to diagnose. It'll be a pain to have to send it back to him twice to get it right, but it looks like the only option for now. Thanks everyone for the suggestions.

 

[vaboom123]

Yea, you'll probably have to do a series of data logging and go back and forth with your tuner. I've tired the mail order tune before, and in my opinion is a pain in the butt. I had great service, but having to load a tune and then go out and test it just takes up a bunch of time.

It was with a svt ford focus and they are a pain to flash a tune. Sometimes it wouldn't work, and I'd have to go back to stock then try re-loading the tune. It would take a couple of tries sometimes haha. Some people even had worse luck and would have the tuner freeze up leaving the vehicle with a no start situation. Then have it towed to the dealer and have the factory tune flashed.

 

[Clevy]

Originally Posted By: vaboom123
Yea, you'll probably have to do a series of data logging and go back and forth with your tuner. I've tired the mail order tune before, and in my opinion is a pain in the butt. I had great service, but having to load a tune and then go out and test it just takes up a bunch of time.

It was with a svt ford focus and they are a pain to flash a tune. Sometimes it wouldn't work, and I'd have to go back to stock then try re-loading the tune. It would take a couple of tries sometimes haha. Some people even had worse luck and would have the tuner freeze up leaving the vehicle with a no start situation. Then have it towed to the dealer and have the factory tune flashed.


I'll never do the mail order tunes again,ever. It's just too much trouble and even though a tune should work and does work on other identical engines engines aren't identical. There are little things different with each engine and a dyno tune can compensate for that because they are adjusting parameters in real time,not data logging and looking for little blips and irregularities in the print out.
A dyno tune also means the tuner is right there,listening to the engine,noticing every little detail,like if it bogged when going full throttle real fast whereas it doesn't happen when you toe in on the throttle etc.
And elevation can make slight differences too. A remote tuner may not be compensating or making adjustments for that too.
I wouldn't be going full blast in that car until you are confident in the tune. A bad tune can ruin an engine. Just ask the oners of tuned 5.0 mustangs that had the rear cylinder cook because the tuner lessened the knock sensor sensitivity.