Ford Industrial Injection pump not pumping

VTPSD · Jul 18, 2013

I have a ford industrial tractor (i think model 420). Was running perfectly but the ignition switch was not working very well so i swapped it out. At the same time I got the oil pressure light working and to test the light I cranked the tractor for a few seconds with the fuel cutoff pulled out to see if my oil pressure light would go out. It did. Went to start the tractor and it started for about 5 seconds, and stalled. Would not restart. I bled fuel at filter and at the bleeder on the pump. Plenty of fuel getting to the pump but only trickles out of the bleeder even when cranking. I applied about 10 psi of compressed air upstream of the filter and it started right off and ran perfect until the compressed air was removed. Then it was the same situation. Did I damage something in the pump by cranking the engine with the fuel shutoff pulled? I am stumped.
The good news is I got my cluster mostly working, the bad news is now my tractor will not run.

VTPSD · Jul 18, 2013

i should add that when i got it to run with compressed air the fuel shutoff worked just as it should. I had originally thought that it may have been stuck.

Jerry/MT · Jul 19, 2013

Sounds like your problem is a clogged fuel filter or some other restriction in your fuel delivery to the pump. Don't continue to use compressed air or your liable to force some crud into the pump.

VTPSD · Jul 19, 2013

fuel flows very freely right to the pump if i remove the feed line at the pump. In fact, if i take the bleeder right out fuel flows out with the gravity pressure from the pump, cranking the engine has no effect on the flow from the bleeder like it should.

VTPSD · Jul 19, 2013

This morning I removed the return line from the pump and checked for blockage, it was clear and its path in the filter housing was clear. Cranking with the return line off still produced zero fuel movement.
I am by no means an expert on injection pumps, but it sounds like my next step should be carefully removing the top cover and inspecting the inner workings there. Does the fuel cutoff stop fuel from reaching the low pressure pump, or just from the high pressure injection side? If it stops flow to the low pressure pump, maybe something went wrong with that linkage inside? I'm a bit at a loss here.