Onan Generator Shutting Off & Batteries???


drewski24

New Member
Can anyone help??? I recently changed the oil and filter in my Onan 7500Kw genny in a 2000 Holiday Rambler Ambassador diesel pusher, and the generators been having starting issues ever since. When I start the genny, it will run for 20-30 seconds and then shut down. It sometimes does this once and starts up and runs on the second start-up, or it will do it twice and then starts on the 3rd attempt (always, never more). It's almost like when it should start to draw on something, it shuts down. I did notice when I turned the water pump on, 45 sec-minute after generator start-up, (which was after noticing the genny was powering stuff - lights got brighter) and it shut down on me. It does it even when I don't have anything plugged in (I believe). It will also go through this start-up process if I shut down the genny, and then need to start it up 20-30 minutes later while its still warm. Could I have screwed up something simple during the oil change? I double and triple checked I put the right amount of oil in, plug back in, filters on tight (not too tight),...The fault code that comes up is just 2 flashes, nothing else.

Does it have anything to do with our new house batteries that seem to die over the course of the day, while running very few lights??? Or is this another problem I'm going to need to start researching??? Shouldn't the house batteries charge throughout the day as I drive???

Does it hurt the generator to run it for only 20-30 minutes in the a.m. while making breakfast, then again while making dinner?
 

drewski24

New Member
Re: Onan Generator Shutting Off & Batteries???

Does it matter how charged the house batteries are, for starting the generator? I failed to mention that we're pretty much full time dry camping, only stopping at camp grounds every 2 weeks or so to dump our sewer tanks, fill our freshwater tank, and plug in for the night. After plugging in last night, the generator started right up this morning...and I guess I didn't ever noticed that the generator didnt start in a campground, because I didn't need to run it.

Which to me, makes me think that the batteries are drawn down, but shouldn't they charge while I drive down the road from stop to stop :question: :question: And what could possibly be drawing down my batteries to have to start the generator once or twice before it wants to keep running?
 

LEN

Senior Member
Re: Onan Generator Shutting Off & Batteries???

Do you get any codes when the gen shuts down. Possible oil pressure sensor that is failing and still works sometimes. Would help to know what rig you have.

LEN
 

C Nash

Senior Member
Re: Onan Generator Shutting Off & Batteries???

How many hrs on the gen? Have you changed the fuel filter? Does it run off propane or the MH diesel tank?
 

drewski24

New Member
Re: Onan Generator Shutting Off & Batteries???

The rig is a 36' Holiday Rambler Ambassador with 260 ISB Cummins engine in it. The genny is a 120 amp Onan quiet diesel 7500 HDJAK series. The genny is only giving me a first lever fault code, and it's 2 blinks, which "indicates shutdown due to a loss of engine oil pressure". I check the oil level, and its fine. Could it be the fuel filter?

The generator has about 420 hours on it, runs off the MH diesel tank, and I didn't change the fuel filter when I did the oil and filter.
 

C Nash

Senior Member
Re: Onan Generator Shutting Off & Batteries???

If the code is indicating oil pressure I would start there. maybe just a fualty switch or connection. Try disabling the switch. Yes, I would go ahead and change the fuel filter. Are you sure the code is low oil pressure and not fuel?
 

LEN

Senior Member
Re: Onan Generator Shutting Off & Batteries???

Sounds like it's the oil pressure sensor. MAybe do a search on the Onan site and get where and how to replace.

LEN
 

akjimny

Senior Member
Re: Onan Generator Shutting Off & Batteries???

Are you sure you installed the correct oil filter? Most oil filters have a bypass valve that opens if the filter gets clogged. If you have the wrong filter, the specs could be off for your generator application.
 
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