On the way to work my fuel pressure began fluctuating between 8 and 14 psi. This was almost constant.
My lift pump was replaced within the last 2k. I was wondering if this is likely to be the check valve I have heard of.
Thanks, CJ

 

I've seen a couple of pumps do this , but they don't fluctuate rapidly . They will be at 12 -15 psi one minute and down to 4 -7 the next...new pumps fixed it both times......if it is your pump acting up , get the new updated one under warranty.

 

I just replaced my lift pump for the same reason. I had to wait until it hit 5psi (the Cummins / Dodge minimum acceptable pressure) for Cummins to Warranty the replacement. If you pump is like mine, it will continue to slowly drop in pressure as it flutters back and forth. I had 3,000 miles on mine when it finally made it down to 5psi.

Good luck.

Ron

 

Thanks guys. Funny how the first one lasted 40k and the second 2k. The weird part is I changed my filter yesterday and at start up I had 16-17 psi. Now this.
CJ

 

AT WHAT LEVEL IS THE FUEL IN THE TANK ? REASONE ASKING IS MINE WORKS FINE UNTIL I GET DOWN TO ABOUT10 GAL OR 3 1/2 "LEFT IN THE TANK AND I EVON HAVE THE CARTER PUSHER PUMP AND WHEN IT GETS DOWN TO THIS LEVEL I CAN SUCK IT DOWN TO O PSI AT WOT.

 

Hey Guys,

I never (well almost never) go below 1/2 tank of fuel. I read several years ago that keeping the fuel above 1/2 tank would help the lift pump (not sure why) and help to cool the injection pump.

Ron

 

Fuel level was between 3/4 and 1/2 tank.
CJ