M1008 Fuel lift pump need HELP

[TedO]

I found my fuel system was losing prime over time, and in order to start it, I would have to go through the bleed procedure by cracking the port on the fuel filter and cranking the engine.
After I got the engine started, I noticed fuel linking around the lift pump. I pulled the pump, and found the plunger was completely frozen. I replaced with a delphi CHFP906.

I noticed the plunger on the new fuel pump does move about 1 cm. When I tried to put on the new pump, I found the push rod fully extended, and I couldnt push it back. I removed the larger plate behind the fuel pump, and I could reach in and remove the push rod. I put some stiff assembly grease on it, and pushed it all the way in, and it stayed there. Interestingly, I turned the crank with a wrench, while my finger was on the end of the push rod, and I couldnt feel any movement of the push rod.

With the rod pushed in, I installed the new pump, tried to go through the prime procedure, but no fuel is coming out of the fuel filter bleed. I pulled the lines off the pump, and still no fuel is in the line from the fuel tank.

1) is there some problem with the fact I cant feel the push rod move when I turn the crank, or is the movement so slight that I am not feeling it? Is there something that I am missing between the push rod and the cam, perhaps something that fell out?
2) Is there a procedure to prime the new lift pump, other than the usual bleed procedure? I cranked the engine quite a few times.
3) Is there some issue with the new lift pump? Is the plunger supposed to move a little bit?

I am not sure what to do now.

 

[WWRD99]

I found my fuel system was losing prime over time, and in order to start it, I would have to go through the bleed procedure by cracking the port on the fuel filter and cranking the engine. After I got the engine started, I noticed fuel linking around the lift pump. I pulled the pump, and found the plunger was completely frozen. I replaced with a delphi CHFP906. I noticed the plunger on the new fuel pump does move about 1 cm. When I tried to put on the new pump, I found the push rod fully extended, and I couldnt push it back. I removed the larger plate behind the fuel pump, and I could reach in and remove the push rod. I put some stiff assembly grease on it, and pushed it all the way in, and it stayed there. Interestingly, I turned the crank with a wrench, while my finger was on the end of the push rod, and I couldnt feel any movement of the push rod. With the rod pushed in, I installed the new pump, tried to go through the prime procedure, but no fuel is coming out of the fuel filter bleed. I pulled the lines off the pump, and still no fuel is in the line from the fuel tank.

1) is there some problem with the fact I cant feel the push rod move when I turn the crank, or is the movement so slight that I am not feeling it? Is there something that I am missing between the push rod and the cam, perhaps something that fell out?
2) Is there a procedure to prime the new lift pump, other than the usual bleed procedure? I cranked the engine quite a few times.
3) Is there some issue with the new lift pump? Is the plunger supposed to move a little bit?

I am not sure what to do now.

High probability you got the wrong lift pump. The pump arm has to be the same as the old one. There's 2 designs. Ones bent...ones straight. I use these pumps off ebay...but if you can't get these where you're at at least you have the correct part number to cross with.

Sent from my SM-S906U using Tapatalk

 

[Barrman]

Delphi HFP906 is the correct lift pump part number. I just put one on one of my engines a few weeks ago.

Besides somehow not getting the pump installed with the push rod against the pump arm. You could actually have a bad pump right out of the box. What about the supply hose to the pump. Did it feel all gooie and was all swollen up?

The lift pump is below the fuel level if you have more than a few gallons in the tank with the truck sitting level. Fuel should gush out of the supply line when you remove it from the pump. Did that happen to you?

I’m thinking coincidence fuel supply to the pump issues, bad pump or bad pump installation.

 

[TedO]

No, the fuel didnt gush out of the supply line. Some came out, then it stopped. I put a little air pressure on the fuel tank, and fuel comes out of the supply hose, but it stops as soon as I take the pressure off. The truck was running fine before all this, just had a fuel leak at the pump. The hose wasnt all gooey. It seemed fine.

After cranking for a while, I took the B-nut connected metal hose off the pump outlet, and it was dry.

 

[TedO]

I have it working now.

With the fuel filter bleed open, I pressurized the tank until fuel filled the pump and came out of the filter bleed in a solid stream. Then closed the bleed and did the crank/bleed cycle 5 times until no more bubbles were coming out. Then I could start it.

This was much more difficult than I anticipated. My lesson: if you dont get gas released when you open the fuel filter bleed valve, the pump is not working. If there is air in the fuel pump, it wont pump.