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Engine/Transmission (1998.5 - 2002) Lift Pump, Round 3 and Maxflow Install

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Engine/Transmission (1998.5 - 2002) Lift pump question

2nd Gen Non-Engine/Transmission Front Springs

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My OE lift pump died at 110k miles in March of this year. I went to Cummins and got p/n 3990105 and put it in. Six months and 10 days later, I was back at Cummins ordering another LP, this time p/n 3990082 (now includes pigtail harness). The Cummins service rep pointed out to me in the manual that the warrantee on these pumps is 6months. I missed the window by 10 days! As a result, I have written a letter to the "Cummins Parts Warrantee Advisor" requesting to be reimbursed because of the known weak link in the lift pumps. Results TBD



The replacement pump I put in back in March gradually began dying by having pressure fluctuate all over the place until last week when the needle stayed pegged squarely on 5psi at all times. Best I can figure, that's the amount of pressure the VP was able to pull despite the dead LP and the filter. I carefully drove home and parked it until this weekend when I replaced it again.



I also installed the Wildcat Maxflow system I bought several months ago. I searched threads on the TDR site and got much helpful install information and hints. Total time took about 5 hours, including LP replacement, and I was really taking my time. Results: AMAZING!



Last LP and stock lines/banjos:

Idle: 13psi

Cruise: 9-10psi

WOT: 5-6psi (Mach II's and TST on level 3)



New LP and Maxflow system installed

Idle 16psi

Cruise 13-14psi

WOT:11-12psi (Same settings).



What a relief and what a difference! I just hope the LP lasts me a while because with the stainless fittings and the bulkier hardware, replacing it again will be a bit more difficult.



Tim

Idle FP is 15psi on the new LP, Cruise is 13-14 and WOT I can pull down to 10psi (Mach II's and TST on Level 3)
 
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