Generator won't run with engine running

[jenronn]

My Onan 8kw runs great and powers everything when coach is parked or even plugged in to a/c. , however if the engine is running it will start up but then die as soon as the transfer switch kicks in.  Also dies if it is running and you start the engine. I am leaving on a month long trip on Monday and need to get it fixed ASAP. Anyone else had this problem or have an idea? 

[Guest Ray Davis]

Chances are you have a battery or batt cables problem. There has been a thread about this very thing over on IRV2, here's a link

https://www.irv2.com/forums/f115/generator-dies-when-the-engine-is-started-542215.html

[jenronn]

Thank you Ray  just checked out that thread, New batteries and cables a few months ago and all has been fine. My problem was different than that in the thread My generator starts and runs with engine running but quits when transfer switch kicks in even with no load at all. yet works fine even when plugged into shore power. Seems to be some isolator or solenoid problem that is not working when engine is also charging.. I'm not up on this  but willing to tackle it if I get some direction where to look.

[Ivan K]

Does it produce a blink code when it dies or is it like if it was commanded to stop?

[jenronn]

Will check for the blink code tomorrow Thanks Ivan ,good point.  It does not sound like it was told to stop almost like an overload or slow shutdown and  the Xantrex panel goes haywire. There are no fault or warning codes  when I check the panel. I will also review manual when I check for a blink code in the morning. 

[Guest Ray Davis]

I would start by flipping the breaker switches on the gen.   See if that males a difference, then turn them on one at a time and note what happens.

Has any work been preformed,  anything electrical done or changed recently?  Could it be related to new batteries?

[wamcneil]

On 6/25/2021 at 10:20 PM, jenronn said:

and  the Xantrex panel goes haywire. 

I had a problem where my xantrex inverter lost its marbles and was shutting down the generator a few seconds after the transfer switch engaged. 
Almost bought a generator ecu board before I figured it out. 
Couple ways to try and rule this out:
Onan troubleshooting guide says turn off the main breaker on the generator. If this solves your problem the issue is something outside the generator. Next, turn the gem main breaker back on and turn off the two breakers feeding the inverter inputs. If this solves your problem it’s probably the inverter. 
cheers

Walter

Edited June 27, 2021 by wamcneil