Fuel Pump Push Rod

I have learned a lot from this forum...thank you very much. I have owned a M1028 for about 7 months. I had a fuel delivery problem and after reviewing many threads, I converted to a spin on filter system. Then after further diagnosis, I found that the fuel pump push rod was broken. This probably broke when the fuel pump came loose and backed off. I discovered the loose pump and reinstalled it, but, did not realize the rod was broken. The truck continued to run for several months, until a few weeks back. I replaced the push rod, and pump. The truck ran stronger ever then it ever did. I thought I was in the clear until today. Drove the truck about 30 miles out of town and stopped for lunch. Returned to the truck and started for a split second and quit. I had tools in the box and started to diagnose what could be wrong. Found I was not getting fuel....so pulled the pump, thinking I may have done something wrong.....pump was ok, rod was ok.....until I found that the rod was not moving up or down when cranked. Towed home.......

Now the big question......what could have failed to cause the push rod to stop functioning?.......I can't find a schematic showing how the rod is driven from the camshaft....and the timing chain looks heavy duty and I can't believe it broke. This truck has less then 15K. So any info would be greatly appreciated.

The lift pump [primary fuel pump]push rod is driven off lobe on camshaft. Timing chains can break, though not a common problem, easy enough to check. Make sure push rod moves freely & not binding. The rod will only move if something [like the fuel pump spring] is pushing against it. It should pretty much fall out when lift pump is removed.

it is Electric fuel swap time

rvmaccargar13 said:

Now the big question......what could have failed to cause the push rod to stop functioning?.......I can't find a schematic showing how the rod is driven from the camshaft....and the timing chain looks heavy duty and I can't believe it broke. This truck has less then 15K. So any info would be greatly appreciated.

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i doubt the lobe is off the cam. make sure the rod moves freely, then crank the motor, look and see if the rod moves. if you did break something you will notice a different sound when you spin the motor over. thanks. mark