doubleclutchinweasel Posted June 26, 2023 Share Posted June 26, 2023 Correct me if I'm wrong, but the hand pump should not pump up and get "tight". It should move fuel even after it is primed. The fact that no fuel is going out the return line suggests that either the return passage is plugged or the inlet is plugged. Sounds very much like an inlet line is completely stopped-up. Any chance the check valves could be installed wrong or frozen up? Can you blow air through the inlet line to the tank and through the return line to the tank? Can you pull fuel from the inlet line with a hand-held vacuum pump? Or, I could be on drugs...again. 1 1 Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/72921-injector-pump-damage/page/2/#findComment-533603 Share on other sites More sharing options...
bwdozerman Posted June 26, 2023 Author Share Posted June 26, 2023 The idler gear isn't worn, and only has a very slight backlash. Seems fine. Hand primer easily pulls fuel from tank to pump. Fuel just won't go from pump inlet to outlet. Can the passage be opened and cleaned to unstick, or does it need specialized rebuild? Any ideas on a source for a replacement? Thanks, Quote Link to comment https://www.bigmacktrucks.com/topic/72921-injector-pump-damage/page/2/#findComment-533608 Share on other sites More sharing options...
bwdozerman Posted June 26, 2023 Author Share Posted June 26, 2023 I'll try blowing air through the lines, but, it seems the problem is internal to the lift pump. Thanks, Quote Link to comment https://www.bigmacktrucks.com/topic/72921-injector-pump-damage/page/2/#findComment-533609 Share on other sites More sharing options...
doubleclutchinweasel Posted June 26, 2023 Share Posted June 26, 2023 43 minutes ago, bwdozerman said: I'll try blowing air through the lines, but, it seems the problem is internal to the lift pump. Thanks, It sounds like a blockage or a bad check valve from the description. I mean, if you can't even hand pump fuel through it, there has to be something blocking the path. And I'm not familiar enough with the internals to tell you what to do or not do. But there are others on here who probably know that pump inside-out. Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/72921-injector-pump-damage/page/2/#findComment-533614 Share on other sites More sharing options...
Popular Post Back In Black Pulling Posted June 27, 2023 Popular Post Share Posted June 27, 2023 (edited) old fuel line sucking shut or something in tank blocking suction clogged primary fuel filter old algae growing in old fuel will block flow try running new fuel line into fuel can with fresh fuel Edited June 27, 2023 by Back In Black Pulling 2 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72921-injector-pump-damage/page/2/#findComment-533672 Share on other sites More sharing options...
fjh Posted June 27, 2023 Share Posted June 27, 2023 21 hours ago, bwdozerman said: I'll try blowing air through the lines, but, it seems the problem is internal to the lift pump. Thanks, yup start at the beginning ! the primer getting hard is odd there should be fuel returning to the tank at that point! Quote Link to comment https://www.bigmacktrucks.com/topic/72921-injector-pump-damage/page/2/#findComment-533685 Share on other sites More sharing options...
bwdozerman Posted June 27, 2023 Author Share Posted June 27, 2023 I'm sending from my laptop, so it might not show up the same. Before I put the lift pump back in, I want to clean and check everything in the crossover chamber to ensure nothing is hung up in there. Fuel does get into the inlet side of the lift pump, but, not to the outlet side. Let me know if you are aware of any precautions I should take before opening this up. Attached photo for reference. Thanks, Quote Link to comment https://www.bigmacktrucks.com/topic/72921-injector-pump-damage/page/2/#findComment-533692 Share on other sites More sharing options...
Popular Post bwdozerman Posted July 3, 2023 Author Popular Post Share Posted July 3, 2023 Cleaned all the check values in the pump. Pump outlet valve was limited most. Crossover passage has pressure relief valve back to pump inlet. Cleaned that as well. Engine started right up and ran good. Just sitting too long seems to be what caused the problem. 2 2 Quote Link to comment https://www.bigmacktrucks.com/topic/72921-injector-pump-damage/page/2/#findComment-534065 Share on other sites More sharing options...
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