revving problems

[93_tsi_fwd]

i recently bought a 91 eagle talon tsi awd. the motor is all stock. recently rebuilt head, new vacuums and sensors. the problem is while your driving, the car spudders at 3000rpm. once past 3000 rpm the car drives good when the turbo kicks in. (next) when the motor is cold the idle revvs up and down, but when its warm the idle is good, stays at 850rpm

need to fix the motor asap for dsm meet on feb. 25 at Denny's in Serramonte Mall

 

[Calan]

Not sure on your first problem, but as for the idle, do a search for idle surge. VERY common and has a whole range of possible causes and solutions.

Mine was an improperly adjusted BISS.

Speaking of BISS adjustment... here's something that isn't mentioned much but is a real "gotcha":

The ECU has two diagnostic modes for timing and BISS adjustment. If you ground just the terminal on the firewall, it is in timing adjust mode. If you ground both the firewall terminal and the 3rd pin of the diagnostic port, it is in BISS adjust mode.

Here's the gotcha... I had left my logger plugged into the diagnostic port and was "adjusting the timing" for 5*. What I didn't realize was that with my logger plugged in, the diagnostic pin was also being grounded and the ECU was in BISS mode. So I ended up screwing up both the timing and BISS

Easy fix... Once I figured that out and did it correctly, my timing and idle are now solid as a rock (knock on wood).

Many other things can cause idle surge though... search around.

Good luck!