Community Forums

radams · 10-21-2010, 07:45 PM

This one is driving me nuts. When my coach engine is running the generator won't run more than a minute. Starts fine but won't keep running. Multiple starts okay but won't keep running. When the coach engine isn't running the generator will run for hours, no prob.

Generator has new oil, coolant, and all filters. Fluid levels are fine and a full tank of diesel. 8K Onan 05 returns error code 27 when fails. Always same error code.

Tested this many times and issue is repeated. So, what the heck? Where is the nexus between the coach engine and the generator?

RV Wizard · 10-22-2010, 02:34 AM

It sounds like someone tied the fuel line from the generator into the engine fuel line. The engine fuel pump is over coming the fuel pump of the generator..

radams · 10-22-2010, 03:37 AM

You know, RV Wizard, I was thinking along the same lines but the unit was running fine until a trip earlier this summer. Can a fuel pump get weak or do they just fail? If it were plumbed that way I would assume that would override the safety feature of cutting off when I get down to a quarter tank. Not good, I wouldn't think, and not sure why anyone would do that.

Still more questions than answers I'm afraid.

radams · 10-22-2010, 07:55 AM

Whoo Boy, am I glad I've got an extended warranty!!! Ran the coach over to Cummins and had them check out the generator and see what's going on. Magnets have started separating on the rotor and it needs to be replaced. May be further damage if the rotor "kissed" the stator, whatever that means, but they won't know that until they get in there. Minimum $3500.00. Holy Smokes!!!

radams · 10-23-2010, 05:42 AM

Turns out to be a known issue of Onans of this ilk. Adhesive used to attach magnets to the rotor has failed so in for a new rotor and possible stator depending on what they find when they get in there. 360 hours usage is all she's got on her. Pretty amazing, huh?

Mike Canter · 10-23-2010, 09:28 AM

So why was the generator shutting down when the motor was running but ran OK by itself? Did you ever figure that out?

I believe a Code 27 is the Controller unable to sense an output voltage.

radams · 10-23-2010, 01:53 PM

Ah, that's the same question I asked them! No good answer I'm afraid. They theorized a possible frequency issue but couldn't explain why or how that would produce the symptoms I had.

Frankly, I think they knew that the unit I have is prone to have the adhesive issue and that's where they went first. We'll just have to see how it works out after they are done. I've had electrical issues with this coach ever since I bought it 15 months ago. I was thinking it was the inverter but maybe it's been the generator all along and the the other issues were just symptoms.

Hope so anyway.

Roadking52 · 10-29-2010, 09:03 AM

Sorry about your problem, but it sounds like you caught a big potential problem just in time. I have experience with the rotor "kissing" the stator, ( it doesn't sound at all like a kiss) and I can tell you big $$$$$ are involved.

Can you tell us what model Onan you have? Maybe we are lucky enough to have the same model and should be checking things out.

Thanks.

fkloster · 10-29-2010, 10:00 AM

Quote:

Originally Posted by radams

Whoo Boy, am I glad I've got an extended warranty!!! Ran the coach over to Cummins and had them check out the generator and see what's going on. Magnets have started separating on the rotor and it needs to be replaced. May be further damage if the rotor "kissed" the stator, whatever that means, but they won't know that until they get in there. Minimum $3500.00. Holy Smokes!!!

Sounds to me like the mechanic decided to soak the insurance company to me and come up with a false diagnosis. Your symptoms could be as simple as a fuel pump starting and stopping. (going bad)

radams · 10-29-2010, 07:51 PM

Here is the outcome boys. New stator but warranty company didn't think the rotor was bad enough to replace. I still have 18 months warranty left so we may revisit that before all is said and done. Put it all back together and everything acted exactly the same except now we got a code 3 problem rather than a code 27. Ran a separate fuel line to generator from the shop and left coach engine on coach fuel. Same problem again but now we know it's not fuel related since each will run fine, just not at same time, and drawing from different fuel sources.

Has to be electrical gremlins so they replaced the inverter although it tested out fine. Result . . . both are running simultaneously. Going to test it on a trip to San Antonio next week so we'll see how it goes. I'd feel better if I could understand what occurred but this has been a tough one. I always try to learn something from each problem in case it happens again but on this one I'll be darned if I know what happened.

Mike Canter · 10-29-2010, 09:01 PM

A Code 3 is a Service Check Fault at the first level and you need to hit the STOP button once to read the second level two digit fault code. A Code 3 is not going to tell you anything.

You should read this post. It talks about an identical problem as what you have.
http://www.irv2.com/forums/f104/onan...d-43188-2.html

radams · 10-30-2010, 05:09 AM

See, now there you go. I didn't know that about hitting that stop button for more info. Thanks for the tip Mike. I'm sure it will come in handy down the road. I did learn something after all.

Mike Canter · 10-30-2010, 06:51 AM

Did you read that post about the Xantrex RS 2000 causing the generator to shut down?

Luckiest Dreamer · 10-30-2010, 08:39 AM

Years ago I had a similar problem in a boat. The generator's fuel line tee'd off of the engines fuel line. The generator had not been used for some time and it's carburetor had gelled up causing an air trap in the line. Engine worked OK Gen. did not. Once the generator's carb was rebuilt the problem disappeared. I later separated the lines! Things are now built more compilcated. That's why I tend to not be a backyard mechanic.