Generator issues on my 21T15 Toyhauler

[Gunwerks1967]

Have a 2025 21T15 Toyhauler, have had it about a year and a half, the Cummins Onan QG 4000 EVAP Generator has never worked. Been in twice to Cummins for service. It flat doesn't start, Cummins has replaced the Fuel filter twice. Been out camping/Hunting at least 8 times with it and had to bring my old reliable Honda generator that starts every time. Have another appointment to haul it into Cummins but growing tired of it. You can prime it and it will not start, have checked everything again and frustrated. Wife an I bought this as our last RV while we creep into retirement. Any advice would be appreciated.

 

[BryanValRox]

Have a 2025 21T15 Toyhauler, have had it about a year and a half, the Cummins Onan QG 4000 EVAP Generator has never worked. Been in twice to Cummins for service. It flat doesn't start, Cummins has replaced the Fuel filter twice. Been out camping/Hunting at least 8 times with it and had to bring my old reliable Honda generator that starts every time. Have another appointment to haul it into Cummins but growing tired of it. You can prime it and it will not start, have checked everything again and frustrated. Wife an I bought this as our last RV while we creep into retirement. Any advice would be appreciated.

When you say won’t start? Do you mean it doesn’t spin over? Or it spins over but won’t start(run).

Do you get the same result at the local control at the genset that you do from the remote switch?

In the most simple terms, you are missing one or more of the following,
Air, Fuel or spark or spark at the correct time.

Has anyone tired running it from fuel supply not connected to the RV?

 

[Gunwerks1967]

I spins, but will not fire up

Same result from both

After 2 trips to cummin so far, they replaced the fule pump twice, when I scheduled the 3rd visit, I actually asked them if that could be an issue, they said they couldnt tell me until I brought it back in. However itf it was, the Cummins Warrantly likely would nt cover that...

 

[BryanValRox]

I spins, but will not fire up

Same result from both

After 2 trips to cummin so far, they replaced the fule pump twice, when I scheduled the 3rd visit, I actually asked them if that could be an issue, they said they couldnt tell me until I brought it back in. However itf it was, the Cummins Warrantly likely would nt cover that...

Well, it would certainly make sense that Cummins Warranty would not cover it, if the root cause was found to be on the trailers fuel system.
If the local facility can’t figure it out, ask them to call 1800 Cummins and open an SR so that additional technical support can be provided to assist them with tracking down your root cause.

Basic fuel system tests measuring restriction and pressure need to be completed, in addition to electrical checks to ensure the ignition system is functioning.

It is a simple check to move it over to a test fuel system to see if it will run.