Absolute latest rev lift pump info and whether you need the harness

[Steve St.Laurent]

Did some research today for you guys on the latest rev lift pumps available (which is NOT the AC pump, btw)



The latest rev D/C part # is 05080885AA (that superceded the AC pump) and that includes both the lift pump and the harness for $397 !



The Cummins part # is 3990105 for $139. 08 and the harness is # 4025182 for $7. 13



You ONLY need the harness if you have a 1998. 5 or 1999 truck - if you have a 2000+ model then you don't need the harness, it hooks right up to your existing wiring. This info was right from the guys at D/C and Cummins that would know. These pumps have just become available in the last couple of weeks.

 

[fj40charles]

Steve, Good stuff.



I've been carrying around a new lift pump for some time. I wonder if Cummins will let me trade up to a newer revision?

I'm curious to know what the newer rev. fixes.



Charles

 

[Steve St.Laurent]

I doubt it Charles. I do know that one of the updates is hardened seats - not sure if they made other changes as well. Another recent change (I think it was on the rev before this one) was to have one pump work for either the 99 and prior and 00+ trucks (hence the wiring harness to adapt it to the 99 and prior trucks).



-Steve

 

[fj40charles]

Thanks Steve. I didn't think so. Just makes you wonder when they keep coming up with new revisions so frequently.

 

[icarus33]

These were the exact PN#'s and prices I got too last week when picking up an oil filter. So, I guess these are the latest one's. Cummins SW had 4 on order so I suppose I'll take the plunge...



ic

 

[CJ Lagos]

How do you know if your lift pump is bad? My 98. 5 with the DDTM seems to run fine but maybe it could be better?



CJ

 

[Steve St.Laurent]

Only way to know for sure is to check your fuel pressures - check out my post on my fuel pressure gauge setup at https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=6113 or for a temporary setup (I'd HIGHLY recommend a full time fuel pressure gauge given the history with the lift pumps) go to https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=22974 and check out JEMOORE's post.



-Steve

 

[EMDDIESEL]

Thats the same part number for the pump i just installed. Cummins had trouble locating one, they said there is a shortage of them.

 

[WyoJim]

Before I put in Guages I checked my fuel pump by seeing how quick it would fill the empty canister on a filter change. Half way through the first starter bump.



On the pressure guage I can pull it down to 6lbs at WOT up a 6% grade, but by the time I hit 90mph it is running on 7lbs.



The funny one though is on the level, on the cruise control at 60mph it stays on 9 or 10lbs. But today it got to wandering around between 5 and 10lbs. Once it got down to 3lbs, so I punched it, expecting it to go to zero, but instead it jumped up to 10lbs and stayed there. After while it wandered down to 8lbs so I pushed the cruise cancel button and it popped right up to 10lbs.

Must be the computer fooling around with it.

 

[CumminsAholic]

EMD, What are you seeing for pressures with the new pump? TIA

Corey

 

[Grandpappy]

Me too!

WyoJim, I had the same problem as you have. When mine went to "0", I about c*#ped I was pulling my 5er and stopped the first chance I got, checked press. with manual gauge and had 14#. Turned out to be a bad sending unit. Called Westach and they sent me a new sending unit, free. I mounted the new unit on the firewall and no more problem. I do think I will pick up a spare lift pump before pulling out again. Thanks Steve for the new P/N.

 

[Kent Kuykendall]

Steve,



Thanks for the post on your Guage install. I copied it and am happy with it. I printed out the your post and it made the jobe easy. Only trouble I think I have yet another bad lift pump.



I will also use the PN's for the revised pump and harness Thanks Guys, And just in time for my trip from NC to OR in a couple of weeks.



Kent

 

[Bigsaint]

Be prepared

WyoJim, watch that gauge !!!! Maybe it's the sending unit, maybe it's not. My first Mallory did the same thing about one week before it's death, thought it was a sending unit failure, I was wrong and found out the hard way. Seems that they, the lift pumps, don't just die, they go slow. A typical sign of a failing pump is the erratic psi's that your are now seeing.



Scott W.

 

[Fred Swanson]

Steve, the new pumps are hard to get. Mine had a 7/31/01 date stamp on it. Cummins SW in Phoenix had to really search for it, too.

Thankfully, they are willing to go the extra step in getting you the part you need.

 

[24V-DSL]

Steve....another piece of info

Steve...



I called Cummins NW to order the new lift pump, 3990105 and the harness, 4025182.



They said the pump and sealing washers were in a KIT, # 3990082. They said they'd throw in the harness at no charge and ship to me, which they did. The KIT was $139. 08 for the pump and $1. 82 for the two sealing washers.



So, I've got the invoice right in front of me which confirms the PN's above. All three items were in the box. The PN for 2 sealing washers is 3935171.



BUT, in examining the lift pump I cannot find ANY numbers anything like 3990105, or any other numbers looking like prior pump numbers.



Is the PN 3990105 supposed to be stamped or otherwise "checkable" on the pump? I have no way of verifiying that I've got the latest, revised pump.



(Of course, now I know that I don't need the harness since I have a 01. 5, but Cummins didn't tell me that)

 

[Ramafid]

I have the 3990105 pump and it works alot better than the origional. I did move the pump to the framerail so that probually got me a psi or two but its night and day after the new pump was installed. Old pump was 12 psi idle 8-9 psi @ 65 and 3 psi at WOT. New pump is 14-14. 5 idle 12-13 psi @ 65 and 9 psi at WOT. The engine sounds alot better above 2600 rpm as well. It sounded really wheezy at high RPM's. Makes me wonder how the injection pump fared?



ps. After running the quarter mile my pump pressure was all over the place. Thats when I changed it. Seems that's the tell tale sign of impending pump failure.

 

[Steve Campbell]

Obviously I missed something in a past thread. What is happening to the wiring harness that it needs to be replaced? Thanks

 

[Ramafid]

I don't think there is anything wrong with the wiring harness, they just changed how the pump wires are connected. Y2K's and up are different and if you have a 98. 5 or 99 and replace the pump you need the new style connecting harness. Kinda looks like a horseshoe.

 

[WyoJim]

Grandpappy and Bigsaint !!

Thanks for the comments you guys. I have to go to Bozeman next wednesday and I will see how the pressure acts. I carry a spare lift pump with me. I also carry a spare thermostat. WyoJim

 

[MidwestMotorman]

pump

One clue to a bad lift pump is the noise. Turn the key forward to IGN and listen to how long it runs to build pressure. A good pump will only run about a third of a second. Before my old pump failed it would run about a second and a half, and had a low tone to it.



I just put the newest new pump on and it runs 15psi at idle. The truck sounded better below 2k rpm, and you could hear the boost better at the low rpms in the exhaust.



If you see white smoke while driving, suspect the lift pump going south as well.