930 shutting off when clutch pressed
 

I have a 86 930. It Idles at 900-1000 rpm when start with no problem. However, when i'm driving and press the clutch for more than 3 seconds the car shut off. This 930 start without pressing the clutch. Any ideas?

It's hard to tell without more info what might be going on.
You do not mention any mechanical failure/noises/clutch issues, so I am going to guess and say that what is happening is that when you are moving with the car in gear and clutch out, the inertia of the car/rotating wheels are helping to keep the engine running.

When you push in the clutch the engine goes to idle. There may be an issue with your air/fuel mixture or distributor vacuum/advance that is causing your engine to not return to a reliable idle. First thing I would check would be vacuum lines, o-rings, decel valve, etc.
Second thing I would check would be distributor vacuumm and free movement inside the distributor.

You may try increasing idle a bit to see if this helps as a work around for now.

Does the 1986 930 have a clutch switch requiring you to have it pushed in to start? If so, faulty switch?

No it doesn't - at least mine doesn't

none of the 930's have a switch, ck out your starter wire or
make sure the clutch cable is not touching your starter wires

you have the idle set a little too lean. mine does that if i get it too lean after adjusting the WUR.

X2 above. When the throttle closes it spikes lean and dies. Try driving it and push the clutch in while holding the rpm at about 2000. If it doesn't die that is your problem.

My 86 930 doesn't have a clutch switch. From a cold start it idle at 900 to 1000 rpm. The car idle forever with no problem (no clutch noise and the engine sound fantastic). It seem as if after driving the car for 2 or more minutes it loose it's electrical power; meaning all gauges goes shuts off with the exception of the rpm needle fuctuate. Therefore, I have to pop start the car while coasting.
It almost seem as if there is a ground, thermo or short circuited issue. Does anyone have the electrical shematic?
PS. Thanks for all the feedback.

930's don't have a clutch switch.

IMO it is a faulty ground, checked the wires surrounding the clutch linkages... However, a faulty voltage regulator could show similar symptoms.

not sure if this helps but i came across the electical plug under the dash which connects the ignition switch. i had this come loose and lost power. Maybe worth a check that it is pushed in correctly.

Thanks for all your ideas. i will check them out and post my findings.

guys,

What is the maximum voltage output of 930/911 Alternator or it's Voltage Regulator ?Is it possible that my reg is generating too greater voltage when under load?

1)The built up of pressure in the engine was due to a wastegate diaphragm.
2)The altenator was producing 10.5 volts which was defective causing the RPM gauge to fluctuate.

Replacing these items solved my problem. SWEET