Engine/Transmission (1998.5 - 2002) New lift pump

[SBoehmler]

Saturday I installed my fuel gauge at 65K and, you guessed it, the lift pump showed 5 lbs at idle on the V44 side. At 60mph the reading was 0-1 with a negative going up hills. The truck showed no other symptoms. Moved the sender to the lp side side and the readings were 8 lbs at idle and 5-6 lbs at 60 mph. Moved the sender back to the v44 side and left it there but verified readings with a manual gauge.



Monday went to the dealer all armed and expecting a fight especially since I have a Prime Loc relocation kit. The dealer tech tried to tell me the 0-1 lbs were normal but I told him I did not believe that since 70% of the fuel was supposed to be returned to the tank and even so, since the idle pressure was below 10 lbs on the lp side, it was still out of spec. They ordered me a pump and said it was now a controlled part and had to provide info before getting the order filled. The pump was in and installed the next day and now my pressure is 9 at idle and 6. 5 at 60 mph.



It wasn't too much of a hassle getting it replaced but it would have been if I did not know the specs to come back with them. They had no problem with the Prime Loc which surprised me. The only thing they said was they wanted to charge me $60 for the extra labor for the extra time to install the lp because Prime Loc was in the way. They ended up not charging me anything.



Noticed this morning the new pump was surging up and down when the truck was cold and then settled down and acted OK. Will have to wait and see how it goes form here.

 

[JCyrbok]

lift pump

What year truck is it. 9 at idle is still "bad. " My 2001 with a weak LP runs 11psi idle, cold start in single digit weather. My WOT psi is just a shade under what your 60mph pressures are (run 5. 5lbs WOT no Bombs). I would check the sender for your FP gauage and check your LP with a manuel gauage. U may have gotten one of the pumps that is bad out of the box.



just my 2 cents.



J-

 

[JCyrbok]

lift pump

What year truck is it. 9 at idle is still "bad. " My 2001 with a weak LP runs 11psi idle, cold start in single digit weather. My WOT psi is just a shade under what your 60mph pressures are (run 5. 5lbs WOT no Bombs). I would check the sender for your FP gauage and check your LP with a manuel gauage. U may have gotten one of the pumps that is bad out of the box. All reading are at the VP input Banjo with a Dakota digital gauge.



just my 2 cents.



J-

 

[Steve St.Laurent]

SBoehmler - you may want to read through this thread - https://www.turbodieselregister.com/forums/showthread.php?s=&postid=41858#post41858 . We found back then (11/00) that the prime-loc created a restriction on the 24v engine that lowered fuel pressures significantly. Here's the data that I collected:



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I had a prime-loc on my truck and it's sitting out in the garage on the shelf now. The stock filter is easy to change on our trucks and with the electric lift pump it's not hard to prime the system (as long as it's working).

 

[SBoehmler]

Thanks for the feedback especially the chart with the info about Prime Loc. Wasn't too worried about the Prime Loc before but looks like I need to remove it.

 

[mikel]

Originally posted by SBoehmler

Noticed this morning the new pump was surging up and down when the truck was cold and then settled down and acted OK. Will have to wait and see how it goes form here.

How cold was it? Is it possible that the grid heaters were cycling? I can see my fuel pressure change when the grid heaters are cycling on my truck. Once they shut off my pressure is steady.



Mike

 

[BillGotthelf]

While I feel the Prime-Loc filter system is a great thing I have removed it from my 99 as I could not get enough fuel through the system for my bombed engine. I have one on my 96 and will keep it as the engine is probably around 250-260 hp. However even with a fresh filter my 99 would stumble on acceleration with the TST box set a 4 or higher. This problem cleared up with the prime-loc removal and return to stock filter. I plan on higher upgrades for my sickly 99 and will be adding the larger banjo bolts, DDIII's, ATS ceramic coated exhaust and possibly a Piers HX50/55 so the prime-loc just won't cut it.