Engine/Transmission (1998.5 - 2002) Lift Pump Power

[#2DSL]

With all Lift Pump problems maybe some of the problems are when the power is going to it or not going to it. When my truck was new Lift Pump would run 10-15 seconds when key was turned on or starter bumped. Now it will not run untill engine is running. I put new Lift Pump on Saturday thinking it was bad old pump had 10 psi at idle and would not run when key turned on or starter bumped. New one has 13 psi at idle but it will not run when key is first truned on or starter bumped, only will run when engine is running. How dose the ECM control this? Is the ECM bad. Or how do you or can you fix the driver in the computer ECM to control the Lift Pump like before when truck was newer.

 

[PSL53]

New transfer pump

After 120,000 miles my transfer pump started acting up. It was right after I changed my fuel filter. At first I thought it was air in the system. The pressure was always 12psi at the best and would drop to 9-10 psi WOT. So I ordered the new pump from cummins and the bored out banjo bolts from Geno's and just finished the install. Now I have 18psi at idle and it drops to 12-14 at WOT. WOW what a difference, I should have done this 50,000 miles ago.

Out

Peter

 

[GKarpen]

The ECM supplies the voltage and current to the lift pump. If I were you I would check for a bad, i. e. dirty connection first with a volt meter. Try some electrical grease on the pins. After you bump the starter the running time is 25 seconds. It is varified by many TDR members and the repair manual. I like some others installed a remote lift pump relay coming off of the battery and controlled by the ECM. This eliminates any power problems assuming you solder your connections. You cannot fix this in the ECM. R&R if it is bad.

 

[CEpp]

one thing ive noticed, is if the motor was just running or still warm, sometimes the lift pump will not prime unles u crank it over... psl53, u have that much psi? i did the same thing and ive changed the lift pump 2x's and still no 18 psi... i wonder if my guage is screwed up. .