i have a 97 dodge 1500 5.9l and i did a pressure test on the fuel pump and came up with the following results:

leaving the pickup to sit a while and cycling the ignition once i had 5lbs;

cycling the ignition a second time and about 15lbs;

cycling the third time and hit about 35lbs;

starting the pickup it still had to crank untill it reached 50lbs. if i shut it off and restarted imediately it would jump up to 35 and crank briefly untill 50lbs was reached. to let it sit and then start it up it would crank untill it hit 50lbs.

when shut off it imediately losses all pressure.

i've been told a few different things that are wrong, 1 it could be a bad check valve or 2 the fuel pump is weak. im not familiar with fuel injection and its fuel supply so i don't want to buy the wrong thing. if anyone could let me know how the fuel pump is suppose to work i would appreciate it.

 

sounds like two possible problems... 1 being a bad fuel pump/or clogged fuel filter and 2 the fuel pressure regulator is shot. when you turn the key on, the pump should prime the system for about 2 seconds & it should be up at 40-45 psi and hold. The fact that it doesn't prime, kinda tells me that it's got a weak fuel pump or clogged fuel filter. The other problem with it not holding pressure tells me the fuel pressure regulator is shot... both of are mounted in the same assembly on the tank.

by changing 1... you will change the other...

Hope this helps.

-steve