Engine/Transmission (1998.5 - 2002) Replaced lift pump - low pressure

[rono]

I replaced my lift pump because I had a max high pressure of only 8psi. With comp set on 1-1 I could pull it to '0' with only half throttle. After the replacement, I have a max high of 10 psi, and can pull it down to 6 on 1-1, have not tried anything higher yet. What could be causing the pressure to be low? On the last replacement it would idle at around 15psi. Could the new pumps be low pressure and higher volume? Any ideas. Oh yea, there is 1. 4 psi drop across the filter. The above pressues are post filter.

Ron

 

[Greenleaf]

Return line/pump mounted pressure regulator? Pinch off a hose somewhere like I do on the fleet of shool bus engines. Checks for a good or bad pump/valve.



In tank screen?

 

[WestTN]

In any given system, no pump will deliver more flow at less pressure. If you have less pressure, then you have less flow.

Have you installed the vulcan relocate kit? This kit will get rid of all the very restrictive banjo bolts. When I installed my new LP, I used the kit, and now I can't drive my pressure below 13 psi. With the original setup, my pressure would drop below 5 psi when driven hard.

I monitor the pressure before and after the filter using 2 sensors and a toggle switch. It allows instant diagnosis.