OK here is my dilemma. When I go to start my car, it will sometimes rev up to 3k like normal then as it drops, it wont hold revs and just falls off and dies. This happens usually once or twice then the car will start and act normal again. Any reasons behind this??? The car holds great vacuum at idle.

 

Look for intake air leaks. I fought problems like that plus squrily idle for ages, until I replaced all the rubber hoses, replaced clamps (especially the one on the plenum from AFM (Air Flow Meter) to turbo intake), fixed cracks and just plain sealed everything between the AFM and the LIM (Lower Intake Manifold.

BTW, Mine's an '87 TII

- k -

 

Yeah ^^^

If not that, if your mechanical idle is set so low that the BAC can't even keep up (or the BAC is dead or missing), that could be something else to look at...

 

How can I tell if the mech. idle is too low?

 

Got FSM? The procedures are in there, but basically you jumper the initial set coupler (to kill the BAC), and then set the idle via a screw to 750 +/- 25 rpms on a hot engine.

If the car dies when you jumper the connector, the idle is set WAY too low. On the S4 NA's, turning the idle adjust screw counter-clockwise increases the rpms...

 

Which connector do I need to jump? I cant find it in the FSM.

 

I have the same problem every now and then. I tested the BAC solenoid valve by unplugging it when the engine was warm (as suggested by Haynes Manual). If the engine drops in rpms or dies, it's good. Mine didn't respond at all. Now all I otta do is find a good BAC valve.