3.2 barely idles

[pete911]

I'm helping a friend with a 3.2 carrera. This car is a mixture a pieces. He put a used 3.2 motor in it and is having problems getting it to run right. At first it ran super rich, with white smoke pouring out of it if we even got it to start. I found a break in the DME harness for the head temp sensor. We repaired this and it starts up now, but will barely idle. If you hold the throttle open a bit it will run with some light popping in the airbox. He thinks this means it is now too lean. We tried adjusting the air bypass screw on the throttle body but there was no change. We tried it from all the way in to all the way out, and it doesn't change the idle. Anyone have any ideas ?

Pete

[WydRyd]

How's the charging circuit at idle? Measure volts across battery at idle and make sure it's around 13.5-14v. Could be a weak/dying alternator. I'm going through this now (low idle, desitation under load, whining from rear, squeaky pulley under load - possibly shot alternator bearings!!!)

Good luck and please post your end results so others can benefit

[ausgezeichnet]

You need to disconnect the Idle Control Valve before you adjust air bypass screw. The ICV will attemot to keep the idle at a constant level.

[mfbarnes]

Before adjusting anything on a motronic motor, do the diagnostics:

check all the components for correct operation, ICV, AFM, reference sensor, speed sensor, head temp sensor.

check that the injectors are operating....check each one. Sometimes the plug to the brain gets messed up and you have no signal to the injectors....happened to me last winter.

Put the crank at Z1, take off the dizzy cap and look for crap in the dizzy. may as well take it out and clean it up now. don't grease it inside.

try another DME relay.

One of these steps will almost certainly uncover your problem.