Engine/Transmission (1998.5 - 2002) Oddball Lift Pump Question...

[stevek]

So tonight while we are out shopping I notice that I didn't hear the transfer pump running when I turn the key on. A quick bump if the starter confirms my thought, she's dead. So we head home to do some surgery and put another pump on the beast, bump the starter one more time to again confirm that there is nothing. Go inside to get some water and head back out to start the job, put the key in to move the truck and guess what--I hear the pump running--WTF? Bump the starter a couple of times, the damn pump pumps everytime! Grab the fuel pressure guage and I get ~12psi? Is there a rhyme or reason for this? When the truck is warm (it was ~85 out and she had been run pretty hard) does the transfer pump not run? Just looking to see if anyone else has noticed this before? Thanks... Steve in CMH

 

[RBSOB]

Steve, my '01 recently started doing the same thing and I have a FP gauge so I can watch the pressure. 95% of the time pressure is OK, occassionally it will drop below zero then bounce around then back to normal. I posted about it, got a few responses and picked up a new lift pump from Cummins {install tomorrow}. Apparently not all lift pumps die all at once, I plan on installing the new one and packing and keeping the old {36k mile} as an emergency spare. Keep us posted on your "symptoms". Jim G