Ok, my replacement lift pump just showed up and Im getting ready to swap it out. My question is, whats the best way to get at the thing? Pull the starter motor and go from underneath or disconnect the brake master and push it off to the side?
I may just have a local guy install it since Im not sure how cold its going to be and I have no garage =(

 

Kawi600,
Be sure and give us an update and let us know if it raises your fuel pressure. Did you buy the pump from Cummins?

 

remove the band at the intercooler outlet and the band at the intake horn, take the tube out along with the boots. remove the fuel filter canister,be sure to drain the fuel out of it first. Now you can see it pretty good. This ishow I replaced 2 other liftpumps on other trucks and works for me.

 

I go at it from the bottom. Usually replace the starter contacts at the same time.

Be careful when removing the old pump that the actuator arm doesn't fall into the engine, sometimes there is nothing holding it on. Pulling downward will prevent this.

Sometimes if the cam is in the furthest outward position it will be hard to compress the spring and get the bolt started at the same time. Bump the starter or turn the alternator backwards to change the position.
Some people use a longer stud with nut to compress the the pump to the block, screw in the other bolt, remove the stud then screw in the stock bolt.

 

good tip bill on using the longer stud to get the pump on, it may be just as easy to just turn the engine alittle but I like it any way.

 

I got mine on from the bottom too. It's not a bad job. The starter bolts can be tight, but other than that, its an easy job. I did have a pit to work in. I think maybe working laying down I would had to lay up on top of something for my arms to be long enough. A board ramped up on top of a block or something. 4x4, taller tires, etc.

 

I bought an overflow valve from cummins that was weird looking.. it had 3 shims of different thicknesses inside and no little 'hat' shaped thing that went between the ball and the spring. The opening was a lot smaller too. The guy at the cummins shop insisted it was the right one for the motor. My mechanic says its the right one after having seen the truck. though the idle pressure skyrocketed from 12 to 29 and pressure at 2k+ RPM dips down as far as 15, thus the need for trying the lift pump. My guess is the pump isnt flowing enough volume at higher speeds so the pressure drops. It needs to be 25-ish I think.
I bought the pump from city diesel, dunno who the mfr is.

 

kawi600 is your liftpump making any noise's at 1800 to 2000rpms? just curious

 

No noises that I can hear over the motor at those speeds =)
I do notice that the primer on mine has a lot less spring force behind it than the new one I got.
I cant think of anything else besides a restriction in the metal lines that could cause it to not flow enough volume. Im a bit tempted to just swap over to all rubber lines, I guess thats going to be next.

 

Anyone know the hose size used on the feed and return under the hood? the metal line to the tank had a pretty large diameter and refused to fit into the hose that seemed okay for the top fitting. I ended up going one size larger and everything was so loose I had to double up on the clamps to keep the fuel from leaking

 

kawi600,
Did the new lift pump raise the fuel pressure at higher RPM's?

 

Quote:

Anyone know the hose size used on the feed and return under the hood?

3/8" feed, 5/16" return

 

Its been too cold to do it myself, and I havent been able to get a ride to the shop, so nothing yet.
Im going to try sunday if the temps get above 35
I read in a post somewhere that you can get fuel pumps from the 8.3 motors and theyll flow more volume. The overflow will circulate it back if its not used. I dont know if its possible to use up the volume supplied by the stock pump though.
Infidel, I had both sizes of hose on me when I did the job and I think it was the return line that was leaking. Its the one that loops up against the motor then down to the metal line? The nipple on the metal line was war too large to get the hose to fit I had to use the next size up which was too large.
Im thinking the best way to do the job is to take the starter off and go at it from under the truck.

 

You could just run the rubber hose all the way to the tank and forget the metal lines.

 

That makes it a lot easier even if it costs more.

When I used to replace just the short section of hose I would stick some needle nose pliers inside the hose end and open them to stretch the id bigger, worked great for getting it started on.