Engine/Transmission (1998.5 - 2002) New Lift Pump Low PSI?

[GILLES]

Hi guys, I need advice. My old LP was giving me 8 psi at idle, 6 at cruising speed and 4 at wide open. I just finished installing a new LP and was realy happy with 14 psi idle and never under 10 at any rpm. Until 10 miles later after installing the &%#@$ thing,

the pressure went down. I just stoped at the grocery store and

I fired the truck and the pressure was 10 at idle,

7 cruising and 4 at wide open. Ever happen to any one? Do I have a bad New LP or ???

Would anyone have advice?

1998. 5 24 valves 2500 quad 4x4 auto,fuel gauge

 

[Pit Bull]

I would change the fuel filter.

 

[TORQUE THIS]

I went thru 3 in 2 weeks, same condition you have. Cummins kept taling them back and replacing them. Still wasn't right after the third one, 14 at idle, 10-11 cruising, and 6-8 WOT. My original pump always put out 12 to 15 under all conditions, till it died!

 

[JCyrbok]

Just a thought, but maybe air in your Fuel Pressure sender/line.



I just installed a new LP on Sunday and had similar things occur, but not as big of swing as you. Now the pressures are right where they should be and are actually higher than on SUnday when I first fired the truck up.



I also agree that maybe take a look at the Filter too to see if you should change it. Maybe got a bad load of fuel along the way.



HOpe this helps



J-

 

[GILLES]

24 hrs later. I changed the fuel filter and no change in psi. still low. I than changed the LP agan. (second one in 24 hrs. )15 miles on this one so far so good. 14psi idle and wont go bellow 10.

Than for the advice guys.