Hey guys,

I have a '99 2.8L Quattro 5spd that is showing plenty of signs of a bad ECU. It idles around 500rpm and vibrates considerably more than it should, occasionally the exhaust smells like rotten eggs, scanner reported every cylinder misfiring, and now the scanner cant read anything and just shows a scrambled screen. Certainly this could only be a bad ECU?

Now, where is a good place to get a new/used ECU from? I've also heard that a dealer would have to program the ECU, is this true if I were to find a used ECU from the same model A4? If that is true, would it be possible to program it yourself with a performance ECU software such as PES' (or whoever you guys feel has the best ECU software)?

Sorry for the wall of text for a first post


Thanks,
Nick

 

You should have started by purchasing vagcom. Then you should have tried a throttle body adaptation (which can be done without vagcom though)

Theres plenty of information available on the bored in the FAQ and other area's

 

Sounds like a bad cat(s) and maybe vacuum leak

 

Might be silly, but the scrambled screen could be a bad scanner?

PES used to make superchargers for the 2.8, getting a tune from them now is damn near impossible, though the gentleman who made the second post managed to do it. APR, GIAC, SpeedTuning are your best best for performance software.

the low/rough idle sounds like a vac leak, and rotten egg smell sounds like bad cat converters like faster says. he's a smart dude.

 

The scanner works when I try it in other vehicles. What Faster said makes sense, but it seems highly unlikely that both would happen around the same time. What about all the cylinder misfires? Earlier today I had misfires detected again (as evidenced by blinking CEL, since I cant scan for codes)

 

You most likely have a collection of problems rather than a bad ECU - failure of the ECU is very rare, to the point of pretty much ruling it out. Disconnect the battery for a few hours to fully drain the power caps, then hook it back up and turn on the key (don't start the engine) for about 10 minutes. Then try rescanning the car. See what happens, then drive awhile and see if you get a CEL to see if you're logging fault codes.

 

Thanks, I'll try this first.

 

I have the same problem with my 1999 A4 2.8L and have tryed all of this and nothing works. I'm at wits end love the car but just dont know what to do. The last time I drove it it ran great the next morning I couldn't keep it started and had no power when i got it in gear.