Running this pump on a 2002 24v cummins. all has been fine the first 60miles after install, then I noticed the PSI oscillating when running at an idle. then the pump would not turn on at start. now the pump turns on and off constantly once it has been running for 10 minutes or so (enough time for the pump to heat up) the pump might stay off for a split second, or 10 seconds, and run time is the same. this happens when it is hooked up to the factory wiring or when it is directly hooked to the battery. the pump is located mid way up the frame rail from the rear axle, away from any heat source. I am assuming the pump is over heating and shutting off, if not this then what is my next step? this pump might have 120miles on it.
When you say that it’s turning off, is it actually turning off or is the pitching changing and pressure dropping off? If it’s a pitch change and pressure drop, I would suspect that it’s cavitating. The 100gph systems suck through the BF1282 filter, so I’d start with changing that. If the pump is actually turning completely off and you’ve bypass the factory wiring as a test, I’d suspect that there’s a problem with the internal pump controller. If you’d like to send it in, we can certainly have a look at it for you. You can send the entire manifold or just the pump itself – whatever is easiest for you.