[xbrit]

Hi, When the motor is at operating temperature and I switch on the lights, heater, brake lights etc the engine will not idle it stalls. Any ideas
72 E body 383 4 speed.Cheers.

[dave-r]

Sounds like bad connections somewhere offering high resistance. Then when you switch on too many things the voltage in the system drops and you don't have enough voltage at the coil.

Try measuring the voltage over the battery at idle. Then start switching things on and see how much the voltage drops as you turn on each thing. Just to see if it is one circuit in particular causing it.

If you have low voltage at the battery try measuring the voltage between the alternator main output and ground. If that is higher try running a heavy wire directly between the alternator output and the battery +ve terminal.

If you have the stock bulkhead connector check the connections there. The stock system has one single wire that takes ALL the system current to one spade on the bulkhead connector. Fron there it goes to the ammeter in the dash before feeding the rest of the car. It is a rubbish system as the spade connector burns out and drops the voltage. There is a re-wire trick to bypass all this.

[xbrit]

Thanks dave-r,
I thought it my be an earth issue, also the coil gets very hot sitting on the inlet manifold, could it be braking down?
Cheers

[dave-r]

The coil being too hot will not help matters but my money is on the wiring.

If you go WAY back to the first few pages of this electrical section you will find a few threads I wrote on subjects such as coils and grounding etc. Checking ground to any part is easy just by measuring to see if there is any voltage between the body of the part and the negative terminal on the battery. But I would start with measuring the voltages over the battery and from the alternator for sure. Then the wire in the bulkhead connector that connects to the ammeter.