Autopsy report

[Shooter]

Autopsied my failed lift pump. ,



53k mi.

Motor OK

vain pump OK

motor shaft to pump rotor coupler broken.



#@$%! #@$%! #@$%!



The motor shaft is a rectangular shaft end, the pump rotor has a round hole with a brittle plastic insert to couple the rectangular shaft. .

There were a couple little chips remaining of the coupler in the pump, the rest were in the filter. #@$%! #@$%! #@$%!



Can not rebuild. Just throw away good motor and good pump head. #@$%!

 

[Jetson]

No wonder they don't last long. The motor on my first pump started sounding bad, like a dry bearing. I could get it to run after I cycled the key 10-20 times. Then it would run all day

 

[wtrenholm]

Thanks for posting. Would I be correct in assuming your truck was a sudden no start, not low pressure? Hopefully more guys will autopsy and post, then we can try to figure out what we can do to improve the system. When and if (more like when) my fails I want to try improve things and hopefully not have repeat failures.



Wayne

 

[RJOL]

... Would I be correct in assuming your truck was a sudden no start, not low pressure?

Wayne... The 24V engines can run with a totally dead lift pump. There is a little suction from the injector pump (VP44)... This is not a good situation for the VP44, as it requires fuel flow for lubrication of the injector pump... With a dead lift pump, the harder you run your truck, the more likely it will start to show signs of power problems, and the more likely you are to damage the VP44...

 

[Shooter]

I have a pusher, but, My lift pump would run ( pump ) intermitantly. The pusher was able to push fuel through the disconnected vain pump head. I never had less than 12#. There was one chip of the plastic coupler that would occasionally get wedged between the shaft and rotor and it would bring the pressure up to 16#'s. If that little piece had not remained in the rotor I would have been rather clueless as to the coupling, I fished around the space between the pump lower housing and motor and found a couple more pieces. I considered using epoxie in the pump rotor hole ( blind hole ) and letting it set up for a coupling but the hole is smooth and the epoxie might just spin in the pump rotor. 52k mi and the pump housing showed no wear, honed surfaces of top and bottom plates showed no wear, no scoring of ecentric bore and vanes still highly polished.

 

[wtrenholm]

Thanks for the info guys. Looks like I'm picking up a fp gauge in the very near future.



Later,

Wayne