BongoCruiser

Driving home late Friday night the A8 started to miss and downshift early as if the coils were going again. I just had all 8 coils replaced last month. After a short period of time the car started to run on fewer and fewer cyl until it finally died and wouldn't run. Tow truck took it to Willow Grove Audi near Philadelphia. They said they suspected it could be the ECM and were going to try to swap the part with another used car. Does this seem like a viable solution? Anyone else have similar symptom or solution? I'm at a loss since it's not my usual dealer and I didn't have my VAG on me when it died. Can I assume a ECM is expensive??

Joe

Mister Bally

I'd just be happy that they are offering to do the swap to determine if that's the problem. If it is, then you or they can buy a new one. They are not the most expensive part on the car. Probably under $1k.

MP4.2+6.0

you can also find those at times for a 4.2 on ebay. Typically simply a wrecked car, usually at a wrecking yard. Bought one for my C5 4.2 at one point. Much, much cheaper than dealer/new price.

BongoCruiser

After a few days waiting for a ECU from a donor car, I ordered a used one shipped in from a yard for $550. The stealer put it in and they reported back that yes the ECU fixed all the ECU problems (like not having any codes, not running on all cyl) and now bad luck-the fuel pump is also bad and thats another $1200. Well I knew it was $1200 cause I just had it done about a year ago. Makes me wonder-was it the fuel pump all along? Could the ECU have damaged the fuel pump or something during the ECU recoding? That's the problem with being stuck with an out of town dealer instead of the local shop I trust. Not much I can do about it now but wait and pay.

A8 LOOONG

I think that would be unusual for an ECU to effect a fuel pump (FP). I am not familiar with our FP's in that I don't know if the ECU commands a voltage range to the FP -- more for increasing demand and vice-versa?

Sorry to hear of your woes.

MP4.2+6.0

but my sense would be independent as well. These things have complicated (read $$) pumping too with their saddle tank internals that then need multiple pick ups and fuel transfers and such. Not known as a big fault area though in my mind in recent models, though they do go out here and there, maybe more so with buried fuel filters and no change interval specified.