Engine/Transmission (1998.5 - 2002) lift pump minimum pressure specs

[Cummins Cowboy]

I know this has prolly been hashed out a million times but i did a search and didn't get quite the answer I am looking for. My dealer has been pretty kewl to deal with and i am sure will fix anything if they can find a way to justify the problem. My truck after hooking of my hopper test gauge reads about 14psi at idle and so far i have gotten it to 4psi unloaded. I bet i could drag it down to 3psi or lower with my trailer on going up a grade. This is with a fresh fuel filter too. Should i tell the dealer to replace the pump, is part of there testing involve a WOT test. What should I say to help them be able to justify replacement if that is what is needed. I am taking the truck in tomorrow morning so give me your best answer quick



Thanks in advance

 

[WadePatton]

8psi is the minimum number kicked around by DC.



But you need to complain of low power or drivability issues. They don't give a hoot in hell what your gauge says.



Hashed and rehashed.

 

[EricBu12]

Seems like it is getting a litle weak... I did a thing to my system and it has made a world of difference. See this thread for what I did. I now have 14 PSI Idle, I have 2 fuel boxes making 331 HP at the wheels... With this system, I go no lower than 11 or 12 PSI at WOT. IT makes the filters last longer and the PSI stays consistent... .



https://www.turbodieselregister.com...d=72391&highlight=My+fuel+system+finally+done

 

[Chief USA]

I talked to the dealer diesel mechanic about this very subject today. They told me 5-7psi cranking and 10 psi idling minimum. I am going to put a fuel pressure guage on it and check.

 

[WadePatton]

Originally posted by rfrazier

I talked to the dealer diesel mechanic about this very subject today. They told me 5-7psi cranking and 10 psi idling minimum. I am going to put a fuel pressure guage on it and check.

Cranking and idling numbers are unimportant, though you might see some correlation. The number that matters is the one you pull when the boost tops out and the R's come up under load.



I tape the Briar Hopper gauge to the windshield for this test on ungauged trucks.

 

[rweis]

I moved the LP down by the tank about 15k ago, zero prob, great psi stock, just added dd2's and comp, still great psi 12psi post filter at wot on 1/1. I do put a fuel additive in EVERY tank to help keep things lubed. I also have put in larger lines see sig.



Absolutely zero lp probs and actually it (lp) runs great! Truck runs great too, just have to pay attention to the go pedal with dd2's and comp. Wanted to see how max boost was developing this am on way to work. Went to max boost (32#) and when it started to drop off of max I was at 85mph in a 55mph zone (started at 40mph to max boost). LP held 12psi into the VP the whole way.



I think the move of the OEM lp makes a BIG difference. I also think that adding lube to the fuel FOR the lp and vp makes a BIG difference. Helps keep the water out as well. Our SE TDR went to Southeast Power Systems (diesel injector / pump rebuilder) and they stressed over and over KEEP THE WATER OUT! Over 80 % of their repair work was not due to structural design component failure, it was due to WATER caused pitting, corrosion, and failures.



They average over 100 pumps in the repair line all the time. All kinds of high psi diesel pumps. Almost ALL of them were water damage. They had a brand of additive they recommend, but they said they did not care what you used, but USE something for the water and the lube as diesel goes to low sulfur by 2007.



Bob Weis