Just bought an 00 A6 2.7T ... stock.. but awesome acceleration.. when it works

Under full load, the car performs badly about 80% of the time. This manifests itself in all sorts of interesting ways. (Problem is semi intermittent)

Off the line, regular city driving, works great.

Off the line, full hard acceleration, pulls perfect in 1st and 2nd gear, but shifting is often harsh. In 3rd/4th (120-130 kph) gear, car gets to maybe 4K rpm, and that all it will do, unless u slack off the petal, and leave it about 1/3 way down and accelerate more gradually and it works fine. If you kick the car down at highway speeds, it may downshift harshly, then gets to 4K and thats about it. Engine seems to pulse, jerks, transmission bucks. Its hard to tell if the car is misfiring, could be, but its more like there is just no power.

I have taken it into Audi, they said its the MAS (Mass Airflow Sensor) (Cost $108, 1/2 hr to replace) I bought the sensor myself, installed it in 5 mins.. no change in the problem (part is non returnable) To try and diagnous the problem, I unplugged the MAS... totally different car. The car does not have the same performance, but it shifts beautifully, no problems with it loosing power at 4K rpm, and no jerks in the shifting or the engines performance. (other than its about 30% less power than when its working correctly)

Any ideas? I would seem to be a MAS related problem. I guess its possible I got a bad MAS from Audi, but I think thats unlikely.

Thanks for the help.

 

maybe a boost issue?? loosing boost perhaps...not sure tho...

 

Welcome to Audi Forums FootIntheGrille!

Since you're new... check out the START HERE! (click this link) link to get a rundown of the lingo/vocab here at audiforums.

Then be sure to search the archives when you have a question. Chances are the question has been asked before (probably several times) and the archives will have plenty of information to answer your question. If you still need answers, please feel free to ask questions.

Don't feel intimidated; we are all a bunch of pretty cool guys (and gals). Feel free to post advice, comments, ideas, suggestions, and even pics.
================================================== ==========================================

Sounds like MAF/S. I'd have the car VAGed to be sure what error codes have developed.

 

Have a OBDM code reader myself, it comes up with nothing.. other than

P0300 - Misfire detected
P1606 - ABS ECU Failure

I know about the P1606 and its going in for repair next week

If I disconnect the MAF, I get a P0102 thrown (MAF voltage too low or something like that.)

the P0300 makes sense, but it does not indicate why. as I said, I HAVE already put a new MAF in and its still the same. Audi said that a MAF can fail and have no code thrown, but I am not so sure. My luck with dealers has never been good, I found today nobody does diagnosis, they just do part replacement at best. My Mercedes is the same way, fricking waste of time to take it into a dealer unless I am ready to spend insane quantities of money to have them try and find the problem.

Anyone know of any GOOD places to take an Audi in Toronto area? Down Town fine cars are friendly.. but not sure they are knowledgeable.

 

Just curious, is there anything else I need to do when I replaced the MAF? I just disconnected the old one, inserted and clamped the new one in. Cleared the code from the ECU. I have been reading about guys that 'reset' the ECU by disconnecting the battery. Is this the same as using the OBDM reader to clear the codes?


-Thanks

 

Did you do a throttle body alignment after the MAF replacement? Not that you really need to do one, but it might be worth a try.

 

Check your TBB for tears.

 

Ooooooooo... excellent audi_first.

I forget about that feature all the time since I upgraded that with the APR BiPipe years ago.

Good call!

 

TBB - Throttle Body Boot (according to FAQ)

- Is that the plastic hose (Black, ribbed, kinda looks cheap/poor quality) that runs from the MAF to I guess its the TB?

 

No, it is the rubber boot that attaches the two intercooler hoses to the throttle body. Undo the front engine cover (one shaped like a triangle) and the boot is directly below. It will have the boost sensor placed on top. You should remove the TBB and inspect it for tears, usualy where the clamps are fitted. Good luck and keep us posted.


Andy