Fuel pressure ??? on my 02

cerickson

cerickson

fullpull108
Joined
Feb 17, 2011
Messages
1,071
On idle the fuel pressure gauge is reading right at 18 psi. Going through the gears the gauge goes down to like 13 to 14 psi. Has never dropped that low before. I don't flog on the truck. I tried turning the comp box off and still get the gauge dropping down. I changed fuel filters about 2 weeks ago. Does this sound like fuel pump problems, or is the vp on it's way out again? Or could it be the gauge itself? I have isspro fuel pressure gauge, and have a fass 95 pump on the truck. Like I said on idle even after the pressure goes down the pressure goes back to 18 psi sitting at the red lights. Any help would be greatly appreciated. Thanks in advance.
 
week over flow valve? it still within specs at 14 psi open and 10 closed.
 
At idle it would hold 18, and under acceleration it would drop to 15. I floored it today and it went down to 10. Didn't go any lower. Have never seen it fluctuate so much till recently.
 
Last edited:
1. the overflow valve has no effect whatsoever on the fuel pressure. Fuel comes into the IP, through a vane pump, then through the rotary pump & back to the return valve.
2. Where is your pressure gauge connectes
3. Do you have a proper snubber (1/8NPT needle valve is best)?
4. Have you changed your fuel filter?

Ed
 
I changed fuel filter 3 weeks ago. Only has 90 miles since filter change. Yes I have proper snubber. Have had issues with snubber and the gauge before. I will get another set of filters and see if that will bring the pressure back up. Side note. Moved truck this morning and at idle the gauge was only reading 15 psi instead of 18 like normal.
 
Electric gauges are known to lose accuracy over time. The only for sure bet is mechanical fuel pressure gauge and needle valve. I typically only see about 1-2 PSI drop from idle to WOT at highway speed. But running a old school AirDog 150 with standard check ball and spring.
 
Just changed filters. Did the job. Pressure went back to 18 psi at idle. WOT drops down to 14.5 to 15 psi. Guess filters were gummed up a bit from the last bit of treated fuel I had in the tank. Thanks again for all the helpful info guy's. Just glad it was something simple. I was figuring it was fixing to drop the vp again.
 
fass low pressure

2000 Cummins fass fuel system about 4 years old. Recently my edge with tell me at turn of key 15psi at start up 13 psi. If you hammer on it on acceleration it will go down to 2-3 psi. New filters , good fuel, even ran some power service.
 
You must log in or register to reply here.
Top