Onan Generator Problems (Have codes)

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Derby6

Well-known member
Joined
May 1, 2010
Posts
837
Location
Wasilla, AK
Going to make this as short as possible, while giving you all the details of the issue and what I have done.
Fired up the generator to fuel up my ATV at the house.  Just as I was finishing fueling up, the Generator died.  When I tried to restart, it ran for a few seconds and quit.  Finally figured out the fault code and it was "13" "UNDERVOLTAGE FAULT"--Fix is to reduce the number of connected appliances.  Sounds easy, but NOTHING was on???
Checked and cleaned plug--No Change
Checked and verified it was getting fuel--No change
Except it looked like it was going to stay running, BUT after a 1-3 minutes it died again.  This time it was fault code "38" OVERCURRENT FAULT"--Fix is to reduce the number of connected appliances and check appliances for proper operation.  Again nothing was on, but I plugged into the house and Fridge, microwave, and A/C all seem to work fine.
Restart of generator and it just shuts down after a few seconds and now went back to the "13 fault code"

When I prime the generator the fuel pump definitely is working.  It seems as if when I prime it for 10-30 seconds it runs and then dies, almost like the fuel pump is not working when the generator starts but works when holding the prime button.  After checking to ensure it was getting fuel I actually was trying to hold my hand on the pump to see if I could feel it running, but that was the time the generator stayed running for a few minutes...Not to mention that 'theory' does not match up with the fault codes I am getting.

I am at a loss and not happy this fathers day.  We have (had) plans to leave Thursday, but a dealer will probably take weeks to get me in and I am worried I am screwed... :'(

In edit: Generator has 117 hours and oil was changed at 106 hours. 

UPDATE:
I flipped my master battery kill switch off and started the generator.  Generator was running fine and then I turned the master battery switch back on.  Could immediately tell there was a bit of a load on the generator and RPMs fluctuated a bit and off went the generator again.  Back to the 38 fault code.  Just prior to that I checked all the battery connections and they looked good, clean, and tight.  Still digging, hope that helps you help me...
Wishful thinking, just went to try again with a heavier load since I saw that in the converter manual, and it turns out I was full of it...Back to the drawing board.
Thinking it is a generator issue since all seemed to be OKAY on house power when I plugged in....
Oh and I am back to a 13 fault code...
 
The Onan control board needs to see proper generator voltage and engine oil pressure to keep running after you release the start switch.  A 13 code means the generator voltage is too low.

Cause could be a defective voltage regulator, but before you replace it check the condition of the brushes and slip rings that couple the voltage regulator output to the spinning field coil.  Look through the cooling slots at the rear of the generator - there are (2) bronze slip rings and they should be clean and shiny, and the brushes that make contact with them should also be in good shape.  If they're not, that's the first thing to make right.

If you're not comfortable working around the electrical parts of the generator, let a pro do the work.  Otherwise, Flight Systems has an excellent troubleshooting guide on their website, and they also make a nice slip ring cleaning tool.
 
Thanks Lou...you kinda solidified my fears that it was 'in' the generator electrical system, not a simple wire issue or something of that sort...........waaaaaay out of my league.  I can't see in the rear of my generator without pulling it, so to the shop it goes.  So much for retiring from the military and enjoying the summer.  1 ATV in the shop and now this.  Hopefully this will be quicker than the ATV which is looking to take 2 weeks just for them to look at...them there is parts order and repairs.
Better look for a job quick, money is gonna get real tight real quick....
 
OUCH...That hurt
Module / Control / PCB Board or what ever you want to call it was shot on generator.  Originally only got 120V but later showed or spiked to 190V :eek:
Replaced by Northwest Cummins, but still had issues.  Searched and found the RV Transfer switch was also fried.  That is out of their realm, so paid that bill and off to an RV store.
I bought a new RV Transfer switch and have it in hand and need to try and install that tonight or tomorrow.  Should be fun...will have to pull the stove/oven so I can have room to work.
As it stands into it for about $700, but am going to contact Onan to see if maybe they can help under warranty.  I am right at 3 years in service and that specific part is only covered for 2 years, but that part failure really cost me big time.  Probably tell me to fly a kite, but a guys gotta try...117 hours for crying out loud!  Everyone I talk to feels the board failure resulting in a spike is also what killed the RV Transfer switch.  Other way around just doesn't add up. (Both are 30 amp units)
Kudos to Anchorage Northwest Cummins.  It did take them a better part of the day to get to me after they told me to bring it in, but a few other jobs beat me in and some didn't go so smoothly.  They bought me lunch and really helped me see what I needed to do.  Not to mention they cut me a pretty good deal on the part cost, they could have easily stuck me with 700-800 just from there before I bought the Transfer switch.
 
UPDATE:
  Well the Customer Service really Stunk.....BAD. :(  Many, many, calls and non returned calls and 'I'll send it up do it tomorrow' lines, BUT persistence paid off, Kinda.  Just got the check yesterday, but they only paid for the PCB board, not the labor to install it, even though it was done by Northwest Cummings.  Considering the situation and they technically could have just told me to fly a kite, I'll take the lil over 300 dollar check and be done with it.
Disappointed with the customer service though.
 
I was having the same problem, seemed to give me a different code every time it shut down but mostly under-voltage. Every time it shut down was when it was unloaded. Never shut down as long as the ac was running.

I read somewhere that oil level was very critical and since it started not long after an oil change, I checked the oil level. It was just a tad below full so I added about a cup of oil. Now the level shows just a tad above full.

Has not shut down again to date. Not sure if this was the problem but so far has worked for me.
 
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