Odd alternator behavior
Posted: Fri Jan 30, 2015 5:01 pm
Hi guys, I hope someone can help me.
I've installed an alternator from a 1999 Mercedes e300 diesel into a 1971 280SE. I have removed the regulator from the original setup as it's built into the new alternator. There are only 2 terminals on the back of the new alternator. I have connected the indicator lamp (small terminal) connection into the corresponding cable on the 280SE harness. The large terminal is connected directly to the battery. When I turn on the ignition, the alternator light on the dash comes on. When I start the car it goes off and the alternator is delivering charge. Up to now, everything is normal.
Problem arises when I switch off the ignition. The engine stays running and I read approximately +5V on the circuits which switch on with the ignition (wipers, lights, indicators, ECU etc.) and the alternator light is dimly illuminated (presumably because there's ~5V across it. It seems like the 5V is enough to keep the fuel solenoid open which is why the engine doesn't shut off.
If I disconnect the small terminal on the alternator, everything works exactly as it should (except the light on the dash, obviously, which remains dark).
I should add that it's a diesel engine.
Any ideas?
Thanks,
Paul.
I've installed an alternator from a 1999 Mercedes e300 diesel into a 1971 280SE. I have removed the regulator from the original setup as it's built into the new alternator. There are only 2 terminals on the back of the new alternator. I have connected the indicator lamp (small terminal) connection into the corresponding cable on the 280SE harness. The large terminal is connected directly to the battery. When I turn on the ignition, the alternator light on the dash comes on. When I start the car it goes off and the alternator is delivering charge. Up to now, everything is normal.
Problem arises when I switch off the ignition. The engine stays running and I read approximately +5V on the circuits which switch on with the ignition (wipers, lights, indicators, ECU etc.) and the alternator light is dimly illuminated (presumably because there's ~5V across it. It seems like the 5V is enough to keep the fuel solenoid open which is why the engine doesn't shut off.
If I disconnect the small terminal on the alternator, everything works exactly as it should (except the light on the dash, obviously, which remains dark).
I should add that it's a diesel engine.
Any ideas?
Thanks,
Paul.
