Engine/Transmission (1994 - 1998) "Rebuilding" lift pump?

[Rhondasway]

I just got the fuel system information from Joe George (thanks!) and am thinking of taking on the rework to replace the O-rings in my lift pump (among other things). Has anyone done this and if so how difficult is it? I have one sitting on my counter I could pop open but I don't have a lot of specialty tools. Where does one get the proper O-rings, aka 'diesel-proof'.

I think I'll also go for the mod on the fuel heater (removal). Can the gaskets, bent hose and such be gotten from Cummins?

Thanks guys. I'm trying to muster up the courage to lay in the gravel in the cold before the rains descend again!

 

[hsmith]

Just thinking, after looking at your footprint, that truck certainly deserves a 'NEW' lift pump.

Impressive numbers.

 

[GAmes]

Cummins carries the gaskets I know, and probably the 90 degree bent hose. That hose is only about $7 from Dodge. Don't forget the fiber grommet on the fuel line going into the prefilter. That is a Cummins part only, ask a Dodge guy for it and you get the deer in the headlights look. I have heard that NAPA stores can match the o-rings. I've never had one leak.

 

[Rhondasway]

Just thinking, after looking at your footprint, that truck certainly deserves a 'NEW' lift pump.

Impressive numbers.

Thanks! I just hate to throw parts at a problem, especially when on a budget. I've ordered the parts I can get from CumminsNW including the grommet (just in case it's bad). Only thing I couldn't get were the O-rings for the lift pump. Apparently they don't re-build. So I'll take it apart and go looking for the O-rings if everything else looks good. I'm going to remove the fuel heater and replace related gaskets on the pre-filter as well as related rubber lines and see where I'm at.

If only fuel leaked out everywhere air leaked in!

Any recommendations for draining the fuel system, or should I just yank a hose and hope not to blind myself?

BTW, I appreciate the input here including the pages of info from Joe George. This is why I'm still a member here and recommend it to every Cummins owner I meet...

 

[Joe G.]

The input and output lift pump fittings are kind of tight, but they unscrew pretty easy. Especially if you have the LP out and in a vise. The push button has the other O-ring. That's even easier, but you have to be careful because the button is plastic. When I replaced mine I took a sample O-ring to NAPA and got matching ones from their O-ring box. You might want to replace the LP mounting screws with studs. That makes putting the LP back on the engine a lot easier.

 

[Rhondasway]

I think I'm gonna dive into this today. Thanks for the info on the O-rings; I've been wondering how to get them. Any worries that they won't be diesel-resistant? I've got a spare pump so I'll break that down first for O-ring size.

The stud idea is GREAT!! I'll be doing that as well for sure.

 

[ata]

Are you sure it's your lift pump making (sucking) air. I've seen the fuel heater, prefilter let air in around the heater electrical connector and NOT leak fuel. The prefilter, fuel heater is before the lift pump. The lift pump usually leaks fuel into the crank case or motor oil out the primer pump pin. Just giving another place to look Rhonda.

 

[The patriot]

Great idea. I have a spare I'd like to recon if you would post the specs on the O rings & part #'s.

My heater went long ago. IIRC when I bought the truck new, about a year later I got a recall on the heater. The factory didnt hook up the wire.

I didnt last long enough IMO.

Eric

 

[Rhondasway]

Are you sure it's your lift pump making (sucking) air. I've seen the fuel heater, prefilter let air in around the heater electrical connector and NOT leak fuel. The prefilter, fuel heater is before the lift pump. The lift pump usually leaks fuel into the crank case or motor oil out the primer pump pin. Just giving another place to look Rhonda.

I was not sure but here's the diagnosis: my truck seemed under-powered under throttle. As a test I flipped on my electric fuel pump (line goes from tank to injection pump) and power came back. This has been going on for some time now and getting worse. Figured it might be air-related, possibly around the lift pump (per reading here). Return hose under head has been replaced already.

Tore it down yesterday and found the following: rust-colored bits and gooey stuff in pre-filter housing; pre-filter is black (they are white new); pump parts themselves look okay, but fuel inside was black with more gooey stuff and little bits of stuff. I believe at minimum I'm getting a fuel/oil exchange from block.

I did the (permanent) heater removal and cleanup, and put assembly back together with new filter/gasket. Easy per instructions. I will use my other pump now with a new elbow hose between. Too bad there's not a "rebuild kit" for these things...

Note on work: I went in from the top, removing air horn, fuel filter, and afc housing, and bungy-ing the wiring harness out of the way (disconnect plug from bottom of head as well). It's pretty open if you do that. I'm putting in a new fuel filter too.

Issues: Napa only has the round O-rings - stock ones seem to be coated metal, thin and flat. I found a stiff rubber type at a hydraulic company called "backup rings" which I tried. They don't work. They bulge like any rubber will in this application. I don't know if there's a slightly different pump than my two, but perhaps injection-related washers are required. (I have edited this now that I tried them)

Also had to go to Tacoma Screw for the proper sized studs that replace the bolts mounting the unit to the block. Those should make re-mounting much easier!

I've been taking pictures and will post after I'm done.

Question: if I want to have my oil tested, where do I go?

Thanks for the support!

 

[Rhondasway]

My fuel filter assembly was filthy! Filter is black, remaining fluid (after draining before removal) contains large, slimy clumps and get this - is BLUE. I do love things that match my truck, but this is weird! I have not used additives in a couple years (they weren't blue anyway). Any thoughts?

Also checked the grommet in the fitting between tank line and the top of the pre-filter/heater (per instructions). It was trashed!! Came out in pieces. BTW, that metal line pops out of the rubber hose from the tank so you can work on it out of the truck.

I installed the recommended studs and what a great thing!! Just double-nutted them to get 'em seated, then stacked gaskets and components. Plenty of room to put the nuts on and cranked it down.

Another tip: you want to rotate your engine 360 degrees from TDC to minimize the pressure on the pump plunger. An old Cummins guy told me that!

Everything is back together now and after manual priming 300 times (not kidding) and turning over for a couple minutes, then resorting to using the electric pump, got her fired-up. No leaks and she runs steady. Road test tomorrow.

Oo.

 

[ata]

Got another place for you look now Rhonda. On my 97 12 valve under full throttle if I stayed in it long enough the engine would loose power. Drove me nuts trying to figure out why. Well my fuel gauge sender quit working so I pulled out the module and there was my problem. The fuel pick up hose was rubbing against a screw that holds the two halves of the module together and rubbed a small hole in it letting air in the fuel line. Didn't have any problems driving normal. So if you still have the problem after your done you can look there.

 

[GAmes]

It sounds like there is algae in the fuel. If there is it will clog the screen in the fuel module inside the tank, which could rob power at WOT. If that is the problem I'm not aware of any fix besides dropping the tank and cleaning it out. Are you buying fuel at truck stops or neighborhood convenience stores?

 

[Rhondasway]

Thanks ata. Great idea, we'll see what happens.

Algae. Hmmm. I guess I have heard of that. It does look like that, actually. I buy fuel all over the place. Lately it's mostly at a newer local Texaco on the Res. Really affordable; now makes me wonder. Any way to test if fuel at a particular place is acceptable? I did develop this problem after moving to this area and frequenting these stations.

Can't I just put a little bleach in the tank? Okay, how 'bout some hopped-up diesel additive? Kerosene? (please don't make me drop my tank)

 

[Joe G.]

I bought a commercial fish boat once that had four fuel tanks totaling 1000 gallons. It turned out to have algae. Kind of like cream colored snot. No way to drop the tank in a fish boat. We used a lot of biocide to kill the algae. At that point we had a lot of dead algae on our hands or black snot. That took a LOT of fuel filters to get the fuel clean. It even plugged up the diesel cook stove. Lots of fun with emergency fuel filter changes in rough seas.

 

[Forrest Nearing]

rebuild a lift pump?! just buy a new one, they're painfully inexpensive

 

[Joe G.]

Rebuilding it is not going to hurt anything. However I don't think it was a bad lift pump in the first place because of this:

Also checked the grommet in the fitting between tank line and the top of the pre-filter/heater (per instructions). It was trashed!!

 

[GAmes]

There is probably a test for contamination and I would do that first. If it is algae dropping the tank is a hassle but not really that difficult. The hardest part is disconnecting the fuel lines from the canister. To remove them requires squeezing the plastic tabs together and pulling the connector off, and that will take some strength. Dropping the tank a few inches gives a better angle for that. Get it as low on fuel as you can. A helper or two makes using a floor jack unnecessary. I think the only other solution is what Joe did, and the accumulated time would exceed the time you would use to drop the tank (not to mention the cost of multiple fuel filters).

 

[kenny61]

tHEY MAKE A SPECIAL TOOL FOR REMOVING THE PASTIC CONNECTOR. aVAILABLE AS A KIT FOR DIFFERNT SIZE FITTINGS. IF i REMEMBER IT ALSO FITS THE A/C CONNECTORS. tHE PRICE IS NOT EXPENSIVE FOR THE KIT.



oooPS cAP LOCK LEFT ON!

 

[The patriot]

tHEY MAKE A SPECIAL TOOL FOR REMOVING THE PASTIC CONNECTOR. aVAILABLE AS A KIT FOR DIFFERNT SIZE FITTINGS. IF i REMEMBER IT ALSO FITS THE A/C CONNECTORS. tHE PRICE IS NOT EXPENSIVE FOR THE KIT.



oooPS cAP LOCK LEFT ON!

Rambunctious marine... ... . :-laf

 

[Rhondasway]

rebuild a lift pump?! just buy a new one, they're painfully inexpensive

Waist not, want not, my friend... Besides, I kinda like to figure out why something doesn't work and then make it work. Not my fault; TDR members have 'enabled' me! :-laf



I would like to know more about getting that biocide. How does a civilian go about procuring that kinda thing? I may do a combination of cures, and thanks for the info on dropping the tank...



And after driving her today, I'd just like to say WAHOOOOOOOO!! She's back! Hasn't felt this good since, oh, January or before. Oo. I did a stretch of 3/4 throttle (most roads around here aren't long or vacant enough for WOT) and she was pullin' hard, but then started to level off speed-wise. I realized to my joy it was traction loss! Sigh...