How To Onan generator problem

[Ivy]

New to this forum. Wandering if anybody got aa idea with my generator trouble. I have a 2020 onan 7000 generator in my tiffin open road. Generator runs find sitting still. Will run for hrs no problem. When I crank up and start down road. Gen goes down after around 15 min and won’t run . Code is 36 which is fuel problem. Changed fuel filter and fuel pump twice. Also tried different oil levels. No luck. Took back to dealer, they had no one to work on it. Thinking about installing auxillary fuel pump. Any ideas would be appreciated.

 

[redbaron]

Has this ever worked properly?

My guess is that the fuel line going into the main tank is not deep enough, and therefore the sloshing movement is causing it to cavitate and run out of fuel.

 

[Ivy]

Has this ever worked properly?

My guess is that the fuel line going into the main tank is not deep enough, and therefore the sloshing movement is causing it to cavitate and run out of fuel.

It never has worked properly. It still shuts down with a full tank of gas. It will run on less than half a tank sitting still.
Thanks

 

[redbaron]

It never has worked properly. It still shuts down with a full tank of gas. It will run on less than half a tank sitting still.
Thanks

You need to fix the fuel line going into the tank. Either there is a kink, or it is too short.

 

[latech]

While driving , the fuel evaporative system valve is closed and the engine module opens a valve(purge valve) that pulls a vacuum on the fuel tank. Then the engine control module monitors the tank pressure sensor to see if it holds vacuum. If it does not codes are set.
While this is going on , the generator starves because the generator pump cnt pull against the vacuum imposed by the evaporative emission system.
You need to vent the tank, without conflict with the engine evaporative system on the coach engine.
Too bad you dont have a dual fuel generator, you could just run it on propane while driving

 

[latech]

You could loosen the gas cap and drive to see if that clears up the problem.The engine will likely set a P0455 evap code, but that is easily cleared. If the problem disappers, then you are on the right track

 

[Ivy]

I have already tried removing gas cap and driving coach. Still shuts down.

 

[Engleman]

New to this forum. Wandering if anybody got aa idea with my generator trouble. I have a 2020 onan 7000 generator in my tiffin open road. Generator runs find sitting still. Will run for hrs no problem. When I crank up and start down road. Gen goes down after around 15 min and won’t run . Code is 36 which is fuel problem. Changed fuel filter and fuel pump twice. Also tried different oil levels. No luck. Took back to dealer, they had no one to work on it. Thinking about installing auxillary fuel pump. Any ideas would be appreciated.

Cummins shop.

 

[Ivy]

Cummins shop.

Been to shop twice. Can’t find a problem. Asked to change out generator since still under warranty. As long as gen starts and carried load for several hours. Cummings will not do anything.

 

[Ivy]

I have already tried removing gas cap and driving coach. Still shuts down.

I keep coming back to your post. I feel that is the problem, even though I removed gas cap. When first purchased I was getting a check gas cap alert. Couldn’t find anthing wrong with cap. Had to clear code on coach a few times, then quit having alert. I have read that on a few times that an auxillary fuel pump may be needed to supply enough fuel to unit. This could be a fairly easy fix. Just not sure if voltage feeding fuel pump enough to carry two pumps. Has a 7.5 inline fuse to pump. Have 2 spare pumps I could use. I changed out previously with not luck. So they should be good.
Thanks for you help

 

[latech]

There must be something wrong with the evap system. The gas cp message is gerated by a series of logic tests run by the PCM.
It could set because of a mechanical failure of the purge valve,or the canister closed valve. or some othe mechanical issue.Like a kinked vapor hose,blocked check valve etc.
There may be a "trap door" at the base of the filler neck that prevents fuel sloshing into the filler neck while driving.
I have seen those "stick" shut, or close too tighly and cause a pressure/vacuum problem

Whatever the issue is, it could be tough to nail down.
To eliminate or verify the fuel tank/system on the coach is the issue, you could temporarily hook the gen fuel supply to a 5 gallon boat fuel cell and drive it to see if the gen set stays running

Maybe the unit is overheating when driving as an airflow problem while moving could be causing it to overheat.Just another thought

 

[Ivy]

Thanks for your help

 

[Tom in PA]

Check the inverter controls, etc. On mine, if the generator is set to AGS,and you manually start it, it will shut down after being on the road a for few minutes. (Got a similar blink code which did not explain the AGS shut down.) Defeating AGS fixed my problem.

 

[latech]

Good post Tom in Pa . I was thinking something electrical ,like battery levels state of charge etc. but I did not think about / realize the inverter being in the loop could be the cause. Good thing for OP to look at.
Excellent post

 

[Tom in PA]

In any event, stay away from Cummins!!!

 

[Ivy]

Thanks, I will

 

[Ivy]

Thanks, I will

Checked the AGS. It is already in off mode. Sure was hoping.
Thanks

 

[Tom in PA]

Mine had the same code blink last summer and was related to overheat, but turned out to be a fan belt stretching to the point where the fan wasn't turning.
Another overheat turned out to be a plastic grocery bag inhaled against the radiator air intake under neath the generator.
I gather from your description that yours is either propane or gasoline-fueled and mine is a 10kw Diesel...so there may not be a way to really compare them.
In any event, I would never take it to Cummins unless it's a last resort.
Bet of luck with it!
-Tom

PS: Have you tried resetting the inverter?

 

[Ivy]

I do have a gas fueled generator. I have reset inverter. No luck.
Thanks

 

[Trina]

We have a 2007 Coachmen Pathfinder we had our RV plugged in and I forgot and started the generator since that it won't stay running it will run 1-2 minutes and shuts off.
We took the RV in to get service and they said they would disconnected from the RV and the generator ran fine but plugged it back in and it would shut down.
Does anyone have and suggestions? CODE .7
Thanks Trina & Scott