Hey everyone, i'm a newbie on this forum, I have a 98.5 1.8TQM, GIAC Chip, Exhaust. I did a couple of searches, and i figured I would post this just to confirm what i think it might be, I will try not to make it to lengthy. I did one of the greddy III turbo timer installs listed on audiworld.com, this one: http://www.audiworld.com/tech/elec98.shtml. Did everything as instructed in the post, tested and worked great for about 3 weeks. One day, when leaving work, i went to start my car and it dies instantly, tried to start again, didn't start. Waited about 2 min, tried again, idled at around 400-500rpm with a CEL. Drive home sucked, car was popping at each shift, and the exhaust just smelled really rich. I stopped at my buddies dealership cause he has a VAG-COM that he's let me before, always worked great. I go to scan it, car won't scan, VAG-COM says controller not responding. So i figure turbo timer issue, disconnected, unplugged battery, checked fuses, ran fuel cleaner, nothing, car still won't scan. Idle is very lumpy, then it evens itself out until i stop again. It actually drives very well, even under load, makes good boost, still pops in between shifts sometimes. My guess is a bad ecu which i think may have been caused by the turbo timer connection. In my happy world, I would like to thing that it's just some sensors but I am leaning on a bad ecu. Just looking for some insight, if anyone has experianced anything similar. Sorry that it's lengthy, Any suggestions would be great.

 

sounds like a vacuum line leak

 

But why would that affect scanning with the vag-com?

 

Well I can't think of any reasons for that. Do you have a Autozone nearby? Take it to them and see if they can pull some codes. It's worth a try, and its free.

 

I guess i should also add that the car has 155,000 miles, but still runs very strong. i have changed the plugs already, i was going to try the o2 sensors next, the coolant temp sensor has also been replaced, as well as the fuel filter about 8,000 miles ago. I will check a vacuum lines for leaks. I will also try autozone to see if they have any luck trying to scan. Perhaps a dirty throttle body? I haven't checked that yet.