Engine/Transmission (1998.5 - 2002) Liftpump change-out experience.

[Lordsman]

I've had a new pump(Cummins Part#3990105) ridin' in back for a year and a half just in case. Well, I decided to get rid of the original as pressure was wavering between 12-7psi and worse(5-6) when it got cold out before warming up. All pressure's are post filter.

I changed it from the top as I did the fuel filter also. What a PAIN, as there's barely room to do it. Anyway after I got it all back together I found a washer on the ground, same type as the one's between the fuel line bolts and fuel line's. Were there washer between the fuel line's and pump? If so one got lost and one ended up in my tool kit! :--)

Took a little to get it started but when it did the pressure rose to 14psi. Checked for leaks, none found, so off on a 15 mile test drive. Pressure stayed at 14psi and hit 16psi just before I got home. One thing, I got a LOT MORE EXHAUST SMOKE when I punched it, especially when shifting from 5th to 6th. Power seems the same, boost up around 26psi(WOT), which was same as before. I've never seen this truck smoke much like it does now, even after previous fuel filter changes. Seems the liftpump made a big difference in that aspect. I worry about the washer I found, but there didn't seem to be any room for one between the pump and fuel line. I hope it didn't fall off the bolt during install.

Those of you who have changed your pumps(OEM) let me know your thoughts. Thanks in advance.

 

[Steve St.Laurent]

Yes, there's two washers on each bolt - one between the banjo bolt and the fuel line and another between the fuel line and the pump - 4 washers total on the 2 lines.

 

[Lordsman]

Thanks Steve, looks like I've got a little more work ahead of me.

 

[plongson]

As bad a it looks to get from the top, wouldn't be easier (even though you have to drop the starter) to get the LP from the under side. I have a lift in my shop so there is no "Lie'n on the ground"...

 

[mcoleman]

Did you remove the filter and housing. I thought mine was easy to change once I removed the filter and got me a stool to stand on.

 

[emarsh]

same as mcoleman

 

[Lordsman]

Yes, I moved the filter aside and stood on a bucket, which seemed about the right height for me. Local Cummins shop

gave me some more washers, and everything was much easier this time around, thanks.

 

[JR2]

I moved my lift pump back by the tank, now it takes about 10 minutes to change mine. .

 

[merryman]

JR2;

I would be interested in hearing the details of your moving your pump. I am interested in doing that also.



Did you live original filter in place?

Change out lines etc?



Vaughn

 

[JR2]

Vaughn-

Moving the lift pump to the rear is not a big project and it really helped my fuel pressure. I used a set of stainless steel lines that another member made for me and I made a bracket from an L shaped strong tie bracket available at Lowes or Home Depot. There are a few pictures in my readers rigs section if you are interested. The hardest part for me was extending the wires from the stock location to the rear of the truck. I cut my stock harness off and extended it, but there is an easier way. You can buy a pig tail from cummins that is used to extend the harness about 5 inches and just extend that pig tail. You also don't have to use stainless steel lines if you don't want to, lots of guys use rubber hose that is rated for diesel. There are many posts about doing this and its not all that different from adding a pusher pump. My only true warning is that you do not want to remove the stock pump mounting bracket as it covers a hole in the side of the block that was used to drive a 12v mechanical lift pump off a cam lobe.



I have a list of the parts you need to build the SS hoses if you are interested, the parts list includes two test ports to measure FP before and after the pump.



To answer your other question, I still use the stock filter set up. My lines go from the tank to the stock pump (back by the tank) to the filter and then to the VP44.



John

 

[merryman]

Thanks John;



I am going to do a relocate; I have been reading all the threads I can find on this subject since my OEM lift pump failed a couple weeks ago. It was the ball valve (never did find the ball!), so I am interested in the idea that the vibration/ hammering from the injector pump may be a factor in that type failure and would like to take an approach that might deal with that issue too--it seems that the rubber hose fuel line might help there, as well as the little pressure tank illflem posted about in another thread.

I notice that you do not appear to have a fuel heater back by the pump and you live where you might experience "winter" now and then. (spent the night in a park/campground near there in 1984) Do you see that as an issue? It would not be where I live, but could be when I hunt elk----especially when I do so in illflem's neighborhood--out of Wisdom Montana.



I have allso been looking hard at the approach Ncostello took. I want to do it soon, but want to be sure I have thought of all the possibilities in advance.

Thanks



Vaughn

 

[pcarlson]

Vaughn,



If you don't want to make your own harness I believe Practical Solutions sell a harness for this relocation.

 

[mediccummin]

John

Did you use 6 o 8an? How far back did you cut your stock hard line, and what did you use to connect to that? ( compression etc. etc. ) What brand fittings and SS hose did you use? What pressures are you seeing and how well is it working with the stock fuel filter location? I'm in a toss up on relocating that also.

Any input would be great. If you have a list could you email me. Thanks Dwayne... ... ... . This my next project since I'm starting on my third pump in only 40k miles.

 

[rweis]

I used 6 (350 hp) BUT I think if you go 500 hp 8 might be a better choice. In the future I will change mine for 8 if I tap the VP.



I moved mine, the pig tail extended works good.



To fix the nylon coupler in the lp:

I put a RACOR 690 pre lp. Filter yes, but you can put a heater in it if you need to for the lp. I also put Stanadyne blue in the tank to lube and lower pour point, ...



To fix the check ball in the lp:

To keep the check ball from beating itself I am going to put a Mallory 4307M bypass regulator post lp set to 14 psi. An experiment, but I think it will stop the ball valve from opening.



To fix the motor in the lp:

Can't do anything about Carter motor wearing out except change it for a Mallory 110 which is rebuildable.



Just some ideas,



Bob Weis

 

[swalls]

About that harness: if you are changing out the original lift pump on a 98. 5, be sure and get the little adapter harness with the new-style connections BEFORE you change out the lift pump. I had obtained a lift pump from a Cummins dealer whose parts people were pretty *uninformed* (to put it politely, ignorant would be closer to the point) about the ISB. I had just bought the used 98. 5 pickup, and I was keeping the pump for a weekend project combined with adding a fuel pressure gauge. Meanwhile I decided to change the fuel filter. Of course that was when I discovered that the original lift pump was *kaput* . It didn't take long to install the new lift pump, only to discover that I was dead in the middle of our very busy shop driveway with incorrect electrical connections. It took the help of two more technicians, a fancy pair of long reach pliers, and about 30 minutes to crimp on new electrical connectors (that starter is right in the way!!) So for anybody else planning this little project, get that wiring adapter harness first!:

 

[JR2]

My lines are 6an. I don't have any problem with the lift pump in the cold. The heater is in the fule filter and it still does its thing to the fuel. After running the truck for a few minutes I usually see the fuel press drop a bit as the fuel in the tank starts to warm from the return fuel warming it.



I will email the list of parts when I am on the computer that has it on it...



JR2

 

[rweis]

JR2,



It should not be any colder than where you are.



Do you do any fuel additive to change the pour point? Is your CTD garaged? Does it sit outside and get cold soaked? I was under the impression that the nylon bushing was stripping in cold weather from sluggish cold fuel.



Bob Weis

 

[Dlginla]

A thanks to all...



About 30,000 miles ago my truck would jump at about 50 to 70 mph (once in a while) while I had a camper and/or pulled my boat.

I was told it was the transmission. . TC. So I set out looking for good transmission's and TC's. In the mean time the truck ran fine without a load... until about 3 weeks ago, it start jumping all the time at about 40+ mph, after doing more forum reading I was lead to believe it was the "LIFT PUMP". So I ordered one online, it came yesterday and I installed it today, it took about 45 mins. only because last night I read this post and you great guys gave me the heads up on the easiest way to do it, remove the filter housing and go at it...



Thanks again for the advice, the truck runs great now!!!!





98. 5 2500 4x4 banks power pack, new lift pump

 

[donyo]

Just upgraded my fuel system a couple of weeks ago. Installed -6AN socketless, blue, fuel line and fittings (. Summit Racing ) from the VP-44 back to the tank. Also re-located the stock LP back closer to the tank along the frame. Custom made an extension line for the electrical from parts purchased from Cummins NW in Renton, WA. They are the same connectors used in the stock application. I cut the stainless hard line back near the tank and added a shut off ball valve for future maintenance use, and also an in-line, 35 micron filter between the tank and LP. Simply slid the new line over the stub and secured it with a screw type clamp. No leaks so far. Pressures seem to be improved over pre-project. Most impressive is the WOT pressure. Before 6-7 PSI. Now 10 is the lowest I've seen