Hmmwv. Not getting fuel (after new pump)

[Stuttgarts996]

3/4 tank fuel maybe a bit more. Just checked for vacuum at the cap, nothing. Also Nothing from the lift pump aside from a dribble. Was an oem pump but I think when installing the rod wasn’t retracted. My own fault. Was a end of weekend project started last minute. I noticed when torquing down the pump it made a metallic ping. I shrugged it off but think that may have been a tell tale sign. Question is would the high pressure pump have the ability to pull fuel through a damagefd lift pump if it had an initial prime. I have a new pump, rod and gasket (both on the way) i have tried bleeding but can’t get the lift to push any fuel. I think I may find it was self inflicted due to lack of paying attention.

 

[Retiredwarhorses]

You can run on a bad fuel pump and never know it’s bad....that is until you open your water separator drain.
ive had this happen while on duty doing PMCS, actually happend on a truck that was over full on fuel on the JI line and needed to be less then a 1/4 tank for loading.
the injector Pump will act as the Pump, that is until you open the water separator drain.

 

[Stuttgarts996]

And I would say your spot on right there. that’s exactly what she did. as soon as I cracked the separator to see if I could get the fuel out of it while she was running it immediately shut down . I wouldn’t of even known that I had a problem if I had gone back out to start after I got to work and noticed a little bit of white smoke at idle which I initially thought I had a little air trapped behind it injector.

 

[tomelroy]

the "metallic ping" you heard when torquing down the pump, was the fuel pump push rod snapping in half! Replace the rod as stated (coated in grease to help hold it up) and i bet it will solve your problem. You may need a magnet to get the upper portion of the pushrod out of the block.

 

[Stuttgarts996]

Thanks for the tip!

 

[Milcommoguy]

Fuel pressure, Go, NO-GO, White smoke signals??? Here's what I did. Epay, Marshall oil filled gauge, 0-15 PSI on the cheap $15. Add 1/8 pipe elbow. Remove the (junk, who uses it any way) test sender on top of fuel filter. Add elbow, add gauge. Build out as shown in pictures. This may not solve your problem, But adds to the ability to self-diagnose fuel pressure in the field. 5 PSI is 5 PSI. No guessing, NO smoke and mirrors.



AND here's another, the "FOR SURE OIL" pressure. Same concept. Same type Marshall Gauge only 0-60 PSI. Mounted on bracket and plumbed (hard lined but could be a short hose) pointed forward to see with hood open. While one can have issues with the in dash military gauges, (mine work right) having a for sure test verification makes life easy... POP the HOOD and PEEK.



CAM

 

[diesel dave]

Had a similar issue with a cucv I owned several years ago. From the very first time I started it,it took a few "cranks" to start. After a year,it seemed to be getting worse. I had always suspected a weak "lift" pump,so I decided to change it.
when I pulled it off,there was NO push rod. Put a used rod back in,and no more weak starts.
yes,the IJ pump will draw fuel to it.

 

[Stuttgarts996]

I had a feeling it would. Parts are set to arrive Friday so it will be my weekend project. Until then I’ll be shoehorning myself and my German Shepard into the 911 to get to work. Wouldn’t be a bad ride if the dog wasn’t such an a**hole.

 

[Stuttgarts996]

Well I’m back in business. was a snapped rod for the fuel pump as suspected , self inflicted so only myself to blame . I will say the thing pumps fuel way more than it ever did before. Before when the truck was running if I cracked the bleeder to drain out any possible water in the fuel separator it would just come out as a dribble now I get a very solid stream. that had to be one of the worst jobs I’ve done in a while the job itself was simple the problem was that the rod snapped off inside the block recessed deep inside and every time I would get a magnet on it the most powerful when I could get to fit in the hole it would pull out partially and then the magnet would come off . I tried using high pressure vacuum Assembly I rigged up to pull it with no luck as well as every other thing I could think of. in the end the only way I got it out was to use some weld mount adhesive on the end The magnet and very carefully position it in place so it wouldn’t touch the inside edge or get any of it epoxy on the inner wall until it set up on the broken section, and then use that to pull it out. I thought for sure I was going to have to dig into the engine to get out of from the backside. What should’ve taken an hour and a half start to finish ended up taking eight total. But it could’ve been a lot worse.