Onan 8kw generator fault codes

kingwood390bh · 06-15-2012, 01:23 PM

I figure I'll fish for more help while I'm at it. My generator(2010 390bh) starts and runs for a short time until a load is applied. When it shuts down three blinks indicate a fault that requires service. It will restart and run till the ac is turned on. It has 110 total hours and was serviced 6 months ago. I checked the oil level and that is the extent of my knowledge. Any ideas?

djorgensen3 · 06-15-2012, 02:25 PM

Go to your local rv store and pick up some plugs and a filter and a can of decarbonizer made by Onan for their gens. I had the same issue. I used the entire can spraying it into the carb until the engine would start sputtering, let it recover, do it again until can is empty. Worked great. I can run both a/c units and the microwave and the electric water heater element in Phoenix 110° heat!

VinceU · 06-15-2012, 04:21 PM

Quote:

Originally Posted by kingwood390bh

I figure I'll fish for more help while I'm at it. My generator(2010 390bh) starts and runs for a short time until a load is applied. When it shuts down three blinks indicate a fault that requires service. It will restart and run till the ac is turned on. It has 110 total hours and was serviced 6 months ago. I checked the oil level and that is the extent of my knowledge. Any ideas?

Agree, sounds like varnish build up in intake system. M/T the can may be damaging due to solvent base liquid may cause excess wear. Problem may very well be varnish from lack of running it or long strored gas in main tank. Suggest following Onan instructions for removal. Build caused by old gasoline evaporating and leaving "varnish" behind. It gums up internals in pumps carbs/injectors etc.

kingwood390bh · 06-15-2012, 08:39 PM

Thanks guys.
I got more info from you than the Onan people. They gave me no clue as to the possible origin of the problem. This diesel unit is a lot more mysterious in its behavior than my last gas generator. I'll hit the camping world on the way home for the materials.

tmmar · 06-15-2012, 09:12 PM

not sure what vinceu mean by varnish forming. That is usually a problem restricted to gasoline engines. Not sure if diesels are affected by a varnish problem.

VinceU · 06-15-2012, 10:22 PM

Quote:

Originally Posted by tmmar

not sure what vinceu mean by varnish forming. That is usually a problem restricted to gasoline engines. Not sure if diesels are affected by a varnish problem.

Sorry, mistaken ID!

LiteEmUp · 06-15-2012, 11:05 PM

With the 3 blinking lights, you can get the second level fault code and this will tell you a more extact reason.

To see the other fault code, when the generator quits and you see the three blinking lights, push down on the generator start/stop button for about a second (either the button on the generator or on your dash) and another series of blinking lights will occur. Count the blinks. For an error code of 27, there will be two blinks, a pause, and then seven blinks. The blink cycle will continue for about 5 minutes. If you still have your manual, the fault codes will be listed. It could be any number of reasons for the shutdown and the manual has instructions to correct the problem for some of the faults.

Also, you can get the second level code without causing the generator to fail again. The last fault code is stored in the generator's 'memory'. Just push down on the generator button and the blick cycle will start.

jonnys_walkers · 06-16-2012, 10:09 PM

Not sure if this is the same genset as you have or not, it is an 8 kw.
Cummins Onan
There is a manual that you can download. Section 4 gives you all your fault codes.

kingwood390bh · 06-17-2012, 12:36 AM

Thanks JW
I have the manual but when the generator failed I was driving and my son was helping with the error codes. We got to the primary code and started on the secondary but never got as far as the ones in the manual. I read the one you sent me and will try to decipher the code tomorrow.

kingwood390bh · 06-26-2012, 11:17 AM

After getting home we checked the secondary fault code. It came up "blink pause blink pause pause blink pause blink". I was told that was a 22. To me it could have been an 11 but who knows. I tried turning off the breaker(no change) then reducing the load(still no change). It will run for a few minutes and then just shut down. My mechanic thinks it might have more to do with carbonization or clogged fuel filter. When he fixes it, I will post the results.

kingwood390bh · 07-20-2012, 01:24 PM

Update to the generator shutdown on my 2010 390bh. Took it to Onan/Cummins in Houston. They had me sign a paper acknowledging that, regardless of repair, I was responsible for $250 to evaluate. They called the next day and said that the internal inverter was failing and that they would replace it(get this) under warranty!!! The cost would have been $1500 for the part plus $500 labor. When I went to pick it up they told me they also waived the $250.

tmmar · 07-20-2012, 01:55 PM

That is great that it was fixed under warranty. How old is the unit?

opps- just saw that you have a 2011 Berk.

VinceU · 07-20-2012, 03:31 PM

Quote:

Originally Posted by kingwood390bh

Update to the generator shutdown on my 2010 390bh. Took it to Onan/Cummins in Houston. They had me sign a paper acknowledging that, regardless of repair, I was responsible for $250 to evaluate. They called the next day and said that the internal inverter was failing and that they would replace it(get this) under warranty!!! The cost would have been $1500 for the part plus $500 labor. When I went to pick it up they told me they also waived the $250.

Great news is they found it and fixed it so easily, must believe the "inverter" forms the power supply for governor and VR control? Regardless I guess lots of companies are tacking on the check out fee, Customers will walk if they have to pay too much otherwise. Only bad news is such a small item costs so much money.

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