Engine/Transmission (1994 - 1998) lift pump

[RBratby]

this is a dumb question but what is the easiest way some of you have found to remove the lift pump? i dont know if mine is bad or not but im upgrading all the fuel system stuff. changing the overflow valve new fuel lines and lift pump. i dont know when or if it was ever changed. i have 205k and i think it is the one that came on the truck. i also have a weird ticking noise that i notice when i pull up next to a wall or another car. im thinking that the lp or the over flow valve may be the problem. what do you all think? thanks for the help.

 

[Ram-Man Cummins]

Yes that is your lift pump ticking.

Your pump has worn out inside and the lift mechanisim is ticking, It will probably only give you low fuel pressure, your cam shaft will most likely be fine.

Goto cummins and get the lift pump.



It can be a fairly easy install.

1. Bar engine to Top Dead Center, Then bar it over another 180-240 degrees. (this sets the cam lobe at the lowest point. )

2. remove the starter

3. remove the fuel lines on the pre-heater fuel lift pump assembly.

4. remove the fuel lift pump and preheater as one. Be careful not to drop the lift pump shaft into the engine when removing.

5. reassemble in reverse.



Its a good idea to replace the fuel filter and clean the prestrainer while your at it.



You will need to prime the fuel system also before starting.

Good luck and take your time.

 

[JGK]

Actually, removing the lift pump is not all that hard. It's the installation that can be a real bi... beast. I'd find a way to check fuel pressure first before I R & R'd the thing. Much cheaper and easier. (I can provide info on that, if you wish set yourself up. ) Replace the overflow valve first, as well, then re-check the pressure. However, if you're determined...



It's been since last spring since I had mine out. Clear all the clutter you can for access, such as removing the fuel filter. Things are kinda tight in there. Be aware that the plunger that runs the pump rides on a special cam lobe. This plunger will come out of the pump simply by pulling on it. Once the hoses are disconnected and the 2 bolts holding the pump are out, just be careful and slow withdrawing it from the block so as not to knock it out.



The difficult part about putting it back on is that it sits at an angle against the block and the bolts holding to the block are in a tight area. The alignment of the bolts relative to the angle of the pump and the block, plus keeping the gasket on, and the fact that you are fighting a little bit of resistance of the plunger against the cam, makes it a real challenge.



I found that before I put it back on, I put my finger in the hole and felt the cam lobe, then had someone bar the engine over until I could feel I was on the low point of the cam lobe. This reduced the amount of push back the plunger put on the pump as I was trying to push it up against the block to get the bolts started.



I think the bolt heads are 10mm. Use a short extension and maybe a thumbwheel ratchet, or perhaps a 10mm nut driver to get them started. You might also consider having one person hold it in place from above while you try to start the bolts from below. Everyone finds their own approach that works for them.



The last time mine was out we were doing a gear case gasket R & R (had to pull the cam - put in a PDR upgrade!) and had the injection pump out and the front of the engine clear. It still took 3 different guys working at it for a half hour before we finally got it on! Fortunately, the 12v lift pumps don't have the failure rate of the early 24v.



As to the click, I, like many others, have had that problem. A new overflow valve seems to solve it, or at least tone it down, in many cases. Be advised, the P7100 pump is a loud clackety device. When standing next to the left fender, it is the source of much of the noise from the engine. I've had mine bench tuned by a Bosch shop and stood there while it was done. The tech wore hearing protectors and I plugged my ears when he cranked it up to an engine speed of 2800 revs. Geez what a racket!



Sorry for the long post - I'm feeling "talkative".



-Jay



PS. I see Ram-Man posted while I was typing. What he said about the cam! However, I replaced my lift pump and I still had the click. So you never know...

 

[Woodenhead]

I did mine from the top. I removed the fuel filter and fuel heater and just reached in with a ratchet at took it out. Yeah putting it in is a bit of a pain but it didn't seem all that bad. Using a longer bolt to make it easier to position with the gasket helps. It was a while ago but I don't thing it took me any longer than a couple hours and a couple beers and I changed the filter and over flow valve at the same time. Still have the tick tick tick though. Oh yeah, when you change the over flow valve make sure you unbolt the clamp/bracket holding the return line in place. Some guys try to just "flex" the line to get it out of the way and can end up with leaky lines later in life.



Good luck,

Mike



Mike

 

[MLee]

You guys that have done this, R&R, would some guide pins work for alignment? of the pump, or, not enough room, just wondering.

Marv.

 

[Andy Redmond]

I use a longer than oem M8 bolt to start compression of the lift pump piston, if the cam isn't in the low spot. The extra 30 mm or so is the difference in frustration.



I also lightly,(tack) coat the good Cummins (also avail thru Dodge) gaskets with some black RTV to help with gasket alignment.



After you change a few you'll get the hang of it.



Follow the step by step previously and take your time. You'll do fine. We all have money on it so don't disappoint us! :-laf



Andy

 

[RBratby]

ill try not to disappoint anyone. the reason im changing it is because that is what i thought it was at first so i went and bought one. now that i have it im going to use it. i dont know if it has ever been changed so im going to do it. im also going to do the over flow valve. i think that is original also. plus piers has it on sale for $49 and that is better than cummins $97. the dealer wants $127. another reason for changing it is because all you guys always talk about how much smoke you have with 370's and a fuel plate. i can give some smoke but not like what you guys are talking about. i have some stuff done to the truck. with all this done on a stock turbo i still cant go above like 1200* wot. this does not sound right to me. thanks for the help and ill post how it goes.

 

[Cooker]

I agree, the first thing to do before replacing any fuel system part for the sake of troubleshooting is to check the fuel pressure. If you don't know where you are at how do you know where you are headed?



9 times out of 10 the a low fuel pressure problem is probably the overflow valve and not so much a lift pump. Typically the biggest problem with a lift pump is the seals and check valves going bad causing a hard start problem. At 205k I'm sure the internal seals are shot in the LP so although you might not get any performance increase, you may get a better starting truck.



The ticking noise can be a real bugger to track down. I agree it is most likely the lift pump causing the sounds but it does not necessarily mean that it is worn out. On both my trucks (I think I can count Dad's as mine since I do the wrenching out it ) the lift pumps ticked like crazy, so bad you thought something was going to come apart or fall off. What caused both of them to stop was eliminating the vaccume I had building up in the tanks. I did this by replacing the rollover valve on the top of the tank. I fixed mine over 40k miles ago and I have not heard it tick one time since. I just fixed Dads last winter and it did tick a couple times shortly after the repair but is has been noise free since.

 

[Woodenhead]

What caused both of them to stop was eliminating the vaccume I had building up in the tanks. I did this by replacing the rollover valve on the top of the tank.

Cooker, can you please explain the rollover valve replacement a little further. I have had the ticking for a long time. The over flow valve and lift pump were replaced because my FP and starting was starting to dwindle. Everytime I loosen the fuel cap (usually after driving a while) I hear air going into the take indicating a vacuum is present. I never linked this to the ticking and never thought it was a problem (TILL NOW ).



I think you've got the fix.



Thanks,

Mike

 

[Andy Redmond]

It's a white "ck. valve" in a grommet on the top of the fuel tank module. It allows air to escape, but no fuel to leak out should you be in an accident and the turn be on its "shiny side. " Although diesel is less flammable than gasoline, we would prefer not to have any fuel leaking in event of an accident.



Here's an illustration for a gasser #13, sorry I can't seem to attach it. I'll try later. About 30-40 from DC.



Good luck

Andy

 

[Cooker]

Mike,



Andy pretty much has it covered. I will see if I can find a pic myself. It can be a little tricky to remove as it is a tight space to work in but it will come out w/o dropping the tank or removing the bed. There is a grommet that it fits into that will make it a little tight during removal. I will see if I can dig up a PN for you. If I remember right I think it was a touch less than $20.

 

[Woodenhead]

Thanks for the info. I've got a pretty strong fealing this'll help if not fix my lift pump ticking. Nice to see I have a shot at getting it out without dropping the tank. The part number would be nice so I don't have to rely on some at the dealer to get the number right (sometimes it hit and miss).



Thanks again,

Mike

 

[Cooker]

I could not find my most recent receipt but the part number on my older receipt is: 52127666 list at the time was $17. 70, the part number for the grommet is: 4002149 list was $4. 35. You don't really need the grommet but for an extra $4-5 it may be worth it in case you bugger your old one up upon removal.

 

[Woodenhead]

Cooker,



Thank you for the info. I'll be picking up the parts next time I'm in town.



Mike

 

[RBratby]

well its done. it took me a long time to get to it but i finally did it. it is a little harder then i thought it would be. i did a little from the top and a little from the bottom. the meathead that had the truck before me did it also. when the first owner did it he stripped one of the bolts holding the pump to the truck and instead of getting a new one he put glue on it. i would like to replace this bolt but what size is it? thanks for everyone help it made it a lot easier for me.

 

[Andy Redmond]

try m8*1. 50 *25-35mm in length