2010 M1123 Fuel Delivery problems

[irwinm998]

I am looking for a little help in troubleshooting a fuel delivery issue on my M1123.
It appears, I am not getting any fuel to the injectors.
I am getting fuel on the return line from the injectors. Had one leaking, fixed vent return hose already.
This is what I Know at his point:

Lift pump is putting out about 5 PSI of fuel after the fuel filter/ separator assembly.
Fuel shut off solenoid is opening, getting 24vdc, and I can here is clicking when plugging and unplugging connector.
Removed injection pump cover, full of clean diesel fuel.
Engine cranks fine, even develops oil pressure.
I do know I have a glow plug problem also to troubleshoot but I know I am not getting any fuel to the Engine. No smoke at all from tailpipe.
I was thinking at this point maybe injection pump needs to be replaced. But, I remember on a slantback last year that had an engine swap, the fuel lines were plumbed incorrectly and that is why it would not start. I swapped the return line to top of fuel pump and it started immediately. 6.5 N/A was replaced with a GEP 6.5TD. SO I was thinking maybe the lines are incorrect on this one also. I followed the lines and they appear to be correct. But not 100% sure.

THis HMMWV was restored, In 2010 at Barstow facility in California, The engine, Trans, Transfer case were replaced. Not sure what was originally in this HMMWV. But it has a GEP 6.5 and 4 speed now.

Does anyone have the fuel diagrams that show the difference in the different models. I have looked an cannot find any online.
Any Suggestions?

 

[Coug]

you say you are getting fuel in the return lines from the injectors, have you cracked the line at an injector to see if there is any fuel getting to it or not?

If you know for certain there is a glow plug problem, I'd fix that first so you aren't trying to fix multiple issues on the engine at the same time, as they can sometimes make issues worse together than they would be separately.

 

[irwinm998]

YEs, Forgot to mentioned that, I cracked a couple of injection lines at the injectors, No fuel at all. Not even a bubble....
If it was just a glow plug issue, I would be seeing smoke from the exhaust while cranking, No Smoke, No fuel right?

 

[Retiredwarhorses]

Your injection pump is bad, very common on these trucks, I’ve replaced many. Folks need to remember they sat for 10yrs In the desert after reset.
i drain all fuel from tank and inspect, replace fuel filter, drain back lines etc...

 

[shannondeese]

Just a simple check you can do. Pull the return line from the top of the injection pump. The check valve could be stuck closed.

 

[ewylam]

I had the exact issue on my 1045A2 and it ended up being a bad fuel injector pump. Mine had sat for so long the off-highway diesel had gummed everthing up. Before I fired the new injector pump I drained the fuel tank and lines and refilled with clean diesel and some fuel system cleaner. Fired right up and has run perfect since.

 

[ewylam]

I forgot to mention I got my replacement pump from the gentleman above. He was very helpful in identifying the correct replacement and the product was clean and as represented.

 

[irwinm998]

Yes, I was afraid of the pump may be bad. I removed the top cap from the pump and everything looked fine good clean diesel and very clean inside. I did drain the fuel tank and put 5 gallons of new clean diesel before I tried to start. So i know the fuel system is clean right now. Even replaced filter.