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Injection pump won't move when turning crank.

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It's a 2003 m1123. I'm looking for diagrams of fuel system. It does have a mechanical fuel pump. Can check valves be accessed from plate above tank? Or do I have to drop tank?
Crawl under and look forward of tank. The metal lines clamped to side of tank lead to brass check valves with rubber hose on each end. You can install a longer hose or gut the valves and put back in.
When i was working on a hmmwv, i noticed a valve had different size bung on each end. Check that before installing a single longer hose. I dont know what is stock. We were installing an aux tank.
 

Mogman

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It does not matter remove both of them, like I said just do one at a time.
 

Mattguy

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If its sucking air at the fuel filter you have a clogged filter (maybe) or the tank sock is plugged (probably). You did have a look in the tank, right???
No, didn't look in tank, becausewhen I drained the 2 gallons of fuel that was in the tank it was clean fuel. I burned it in my torpedo heater. I was thinking maybe the sock is clogged. If check valves are clean that will be my next step. It's starving for fuel.
 
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Mattguy

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I put a new filter in but maybe it got clogged from all the crap diesel that was still in the line. I'll pull fuel filter. It's new. And I sonic cleaned the strainer.
 

Mattguy

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I pulled line off fuel filter and dry. So I just pulled hose off fuel pump and am going to see if I can pull fuel to there with a separate piece of hose with barbed connector. If I can't pull fuel then it would be check valve or sock I believe.
 

springer1981

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I pulled line off fuel filter and dry. So I just pulled hose off fuel pump and am going to see if I can pull fuel to there with a separate piece of hose with barbed connector. If I can't pull fuel then it would be check valve or sock I believe.
Have you checked to see if you are getting fuel to the pump and then check to see if it is pumping?
 

Mattguy

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I just tried sucking on the fuel supply side of the fuel pump with extra piece of hose and can't pull anything. So it must be the check valves or the sock in the tank. Do I have to drop the tank to get to the sock or can I get to it from the access cover?
 

Maxjeep1

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I just tried sucking on the fuel supply side of the fuel pump with extra piece of hose and can't pull anything. So it must be the check valves or the sock in the tank. Do I have to drop the tank to get to the sock or can I get to it from the access cover?
Drop. Clean up the inside and replace the gasket so you can fill it without leaking out of the top. I need to do the same thing now. I replaced the sending unit and I could see it was clean inside through the hole but you can’t really do anything but remove the sending unit thru that access hole
 
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Mattguy

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A check valve is often a spring loaded ball and seat. You a compressed air hose to check it. Your lungs might not be able to overcome the spring pressure.
Took apart and cleaned. Pulled c clip and carb cleaned all parts. Used compressed air and it blows air through. But not blowing through with my breath. Should I eliminate or just put back?
 
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