Community Forums

ColoradoBnd · 07-02-2019, 12:26 PM

I know about the fault codes, I am about to go back and I will pull the second code and post it here 3-?. Here is my question. I am just getting it back from RV service and of course the house batteries are completely dead

. So I try to start the gen to begin charging the house batteries. It starts, runs a few seconds and shuts down. I notice that the fuel level in the coach was below the 1/4 tank level. So I assume it is the low fuel cutoff. I put 130 gallons of diesel in the tank and try it again and the same thing happens.

I have had no problems with this gen and it is very low hours. I'm just suspicious that this popped up suddenly when I tried to start it less than 1/4 tank. Anyone had anything like this happen or have any advice?

Ricci · 07-02-2019, 03:13 PM

Hi - You may have to put a charger on the house batteries for a while if they are completely dead.

Tom

twinboat · 07-02-2019, 03:16 PM

If you only tried starting it once since fueling up, you may need to hold it in prime for a minute or so before it gets fuel up to it.

ColoradoBnd · 07-02-2019, 04:23 PM

Looks like I did cause the problem! Ugh....code 36. When I went back today it cranked, but wouldn't really run. The more I cranked the better it got, but I decided to wait versus cranking on it forever. Here is the description of the code:

"Cummins onan generator flashes code 36. Fault #36 happens when the engine stops running due to a reason unseen by the controller /inverter unit. The most common cause of this is running out of fuel , so you may want to replace the fuel filter as a first step."

It now feels like it is not getting fuel. Im going to fully charge the batteries. How does the prime feature work on the Onan???

Semituff810 · 07-02-2019, 10:23 PM

Try changing the generator fuel filter. Can’t hurt.

SeattlePirat · 07-02-2019, 11:14 PM

Check the coolant

Renipladlo · 07-02-2019, 11:25 PM

You go out to the genset, using the control on the genset, hold down until it try's to start. Push to stop, wait for 5-10 seconds, push the button to start, it will prime again, and again it will try to start, if it runs, all is well, if it stutters, stop, wait, try to restart again. Had air in mine once, took about 10 tries before it ran correctly. Don't run starter for more than 30 seconds, you will cook wires/starter. Again, if this does not fix issue, change the fuel filter, and again you will have to purge air from it, by doing above process above.

FatChance · 07-03-2019, 08:24 AM

If priming doesn't do it, check the fuel lines. In our 2004 MADP the 7.5QD is on a slide and the fuel lines got pinched a couple times when the slide was closed. I had the same symptoms you have when that happened. I finally had to re-route the fuel lines and the problem went away. The diagnostic for this is to pull open the generator slide and see if the generator works with the slide open.

palehorse89 · 07-03-2019, 08:27 AM

Hold the stop position/button down, red light will flash and fuel pump will be priming. Hold it for 30 seconds or more then press the start position.

ColoradoBnd · 07-28-2019, 09:14 AM

That worked. Thanks! I guess there is a shutoff valve that kills the fuel when I’m below 1/4 tank? I would have thought it would have just been a generator kill signal electrically.

bigchick · 07-28-2019, 09:29 AM

not a shutoff valve!. the generator fuel line is only extended into the fuel tank so that it ends above the 1/4 full tank fuel level. thus when you had 1/4 tank of fuel the end of the generator fuel line was not in the fuel and it was sucking in air from the tank. that put air in the line and that is why you had to prime it.