Onan 2500/2800 remote crank not working

[TaxWonk]

Onan model 2.5KVFA26120L, though I think all of the 2500 and 2800s are the same for the remote start panel.

I should mention that I had exercised the generator last week before a trip. On the trip we had a tire blow out. The blow out bent the generator exhaust pipe. The exhaust pipe is a solid pipe from the generator to the end of the pipe. So the generator took quite a shock.

I can crank the generator with the panel on the generator, but no crank with the remote in the RV. The switch appears to function correctly. Though the wiring diagrams are not clear to me. I have checked the wire from the switch to the plug just out side of the generator and all four wires are good.

On the switch side of the plug (male end) I can see that pins A & C connect for Start and pins A & B connect for Stop. E-F I think is used for the generator run light. On the generator side (female end) of the plug I see socket A is ground, socket B is battery voltage 12+ volts, socket C is 5.8 volts (this one does not seem correct) and socket E-F has no voltage/ground when the generator is not running.

So the question is why am I seeing 5.8 volts on socket C? Is this correct? When I short A & C on the generator side I expect the generator would crank, but it does not. Maybe because the voltage is too low.

I was really hopping to not have to pull the generator from between the rear wheels to fix it.

Any suggestions would be greatly appreciated.

[TaxWonk]

I pulled the generator and replaced the control module with one from FlightSystems https://www.flightsystems.com/p-56-5299-00.html
Problem fixed.

[rowiebowie]

Originally Posted by TaxWonk

I pulled the generator and replaced the control module with one from FlightSystems https://www.flightsystems.com/p-56-5299-00.html
Problem fixed.

Thanks for the followup and part link. Seems we've had a rash of non start problems with Onans lately. Congrats on the fix.

[TaxWonk]

Just following up as it has been couple of months and a few more hours on the generator. Everything seems to be working well.

[themexicandoctor]

Good information & Thank You.

Do you think the impact was the cause of the failure?

The last few weeks I have had intermittment starting problems, for no rhyme or reason the unit will sometimes start but only after climbing underneath, taking the cover off & using the physical start switch at the generator itself.

Recently that doesn't work.

But then I will get back up into the van, use the Remote Switch & sometimes the unit will start.

Last night, in the middle of the night, I checked the oil & found it at the low mark, filled it up & after a few attempts from under the rig & at the remote switch, it started & ran beautifully.

I used Mobil Super 10W 30, Synthetic Blend.

[CareyM]

07 RT190P , generator well exercised w good oil level and had 7/8 full main fuel tank. gen simply would not start even with engine running. took it to my cummins onan big truck depo: it took them 15 minutes to find the fuel pump on the gen w as shot. fuel pump-- readily available. had to drop the gen to replace the tank, so the repair ws about $650.

the tech said many mechanics who don t know what they're doing on onan tell you you need a carb placement , charge you for it, still no joy. he said the fuel pump on the onan is not well protected from rood grime so they see these failures lot . if you are older than 10 yrs and in a state where they use a lot of road salts, check your onan's fuel pump pressure .

[TaxWonk]

The control board is fully potted, maybe there is a relay that was getting weak on the board. Not sure the impact caused the problem but the timing is suspicious.

[mkguitar]

Originally Posted by CareyM

15 minutes to find the fuel pump on the gen w as shot. fuel pump-- readily available. had to drop the gen to replace the tank, so the repair ws about $650.

Some DIY mount a replacement fuel pump, filter and petcock valve outside of the Onan for easy fuel shut off, filter service and pump replacement if required

[TX-Trek]

Originally Posted by mkguitar

Some DIY mount a replacement fuel pump, filter and petcock valve outside of the Onan for easy fuel shut off, filter service and pump replacement if required

Thanks for posting the control board fix and follow-up, always good to see results.
I'll be doing the fix that Mike posted if/when the pump on our 2800 fails. After checking board and circuits 😀. I think that this is a great solution that allows an eaay on the road fix later if needed.