What’s that loud banging noise?

[thehippie]

What’s that loud banging noise from my cummins Onan 4000 generator? This generator is brand new less than 10 hours of use.

Sometimes I would hear a loud banging that sounds like somebody hit my RV.

[Lazer3]

Ours sounded like a woodpecker was trying to get through the siding. I fixed a lot of problems so I don't know which one stopped it. The altitude dial was set at sea level and we were at 6000 feet. I figured out that it was the fuel pump knocking. Fixed two other issues. Where the factory installed the clamps around the fuel lines, they had beat them flat to hold the hose tighter. The problem was that they crimped the fuel line shut. Also, the lines were right next to the exhaust and were over 140 degrees in a couple of spots. Insulated the hot spots and cured the vapor lock. We have almost no noise now.
Good luck.

[mgirardo]

Our Onan 4000 never made a banging sound, even after 8 years and 400 hours of use. I'd take it back to the dealer and have them fix it.

-Michael

[thehippie]

jerseyjim wrote:
Brand new? 10 hours? Take it back to whoever you bought it from. Gotta be a warranty......

it came with a toy hauler I bought .

It’s a 2018 powerlite 29fbxl From Pacific Coachworks

[gbopp]

thehippie wrote:
not necessarily in first firing.

It comes and goes. Doesn’t Happen all the time. I thought somebody punched my RV

What RV? Maybe giving us the make/model will help.
Could the exhaust pipe be mounted in a way that the expansion/contraction is causing movement against the RV frame?

[jerseyjim]

Brand new? 10 hours? Take it back to whoever you bought it from. Gotta be a warranty......

[thehippie]

afidel wrote:
When first firing up? If so probably the Automated Transfer Switch (ATS) which switches your AC power from line power to generator. Just a guess on my part but working around generators and ATSs for a decade I know that the ATS is the most likely cause of a banging noise.

not necessarily in first firing.


It comes and goes. Doesn’t Happen all the time. I thought somebody punched my RV

[afidel]

When first firing up? If so probably the Automated Transfer Switch (ATS) which switches your AC power from line power to generator. Just a guess on my part but working around generators and ATSs for a decade I know that the ATS is the most likely cause of a banging noise.