gen starting kills coach engine

[scottginfla]

My 1994 fleetwood pace arrow, cummins 250hp 8.3l pusher has a problem, if you start the gen while coach engine is running, the coach engine will shut off, no mater if parked or traveling down the road, but you can start the gen first, then coach engine and all is fine. don't know where to start, the gen is a onan 7.5 DKD diesel. The coach engine is all mechanical, except for the fuel shut off solinoid, so the only way to kill a diesel is stop the fuel, so somethings up.Any help would be greatly appreciated, Scott

[ernieh]

I the Cummins is shutting down while the generator is cranking, I would suspect that some kind of "back door circuit" or "ground interrupt" is being caused by the generator starter relay or start switch(s).

No experience with this problem, just a general troubleshooting thought.

Good luck.

[RustyJC]

If you have a voltmeter, monitor the voltage on the fuel solenoid wire on the Cummins (with it running) and try to start the genset. I'll bet the voltage is dropping low enough to trip the fuel shutoff solenoid. This could well be a grounding issue or dirty/loose battery terminal connections (if there's still some voltage present) or a relay/switch issue.

Rusty

[scottginfla]

Ok, I will test voltage @ fuel shutoff on coach engine, but if voltage drops, where should I start looking for a bad ground? I think there is only one wire at the shutoff, so it must get ground from the engine, does this sound right? If so then I need to check the engine ground strap(s) ? I do not have the wiring diagram for this coach. The battery terminals are all good so thats not where the prob is.