Stumbling and stalling out CUCV

[cucvrus]

I have an 86 CUCV M1009 that just started acting up. Yesterday it was idling and just shut off with out warning. I tried to start it it acted like it was out of fuel. My son bleed the fuel filter and air came out. Then we started it and it ran fine. Today I got on I81 and I said this is lacking power we thought well fuel filter. Then it ran fine for or trip to Rausch Creek. When we got on the trails it started to stall out same scenario. Bleed the fuel line at the filter. It would start and stumble and run fine for a while. Then it became more frequent. It would stall and shut off and bleed start and go. Put a new fuel filter on it and wheeled some more and it kept getting worse. Finally it shut down completely. I was towed back to camp by a 5 ton tractor. We left it sit bled it and got it started. In gear and away we go south bound. We left the park and it stalled and shut down. We coasted onto I81 and stop and did the Bleed crank start thing. We hop on 81 S and away we go. It shuts off and we coast till it stops rolling do the same thing and go again. We made it home. I am thinking injection pump. Anyone else want to give me a guess? I pulled the top of the injection pump off and it is full of clean fuel.

 

[Drock]

Well again I'm new to the whole diesel thing, but I've learned over the years of making crappy cars run against their will, that sometimes the simplest answers are the best solutions. If bleeding the filter makes a difference then I'd say your problem lies with it. Is it still the original style box filter? As we all know those are notoriously leaky and unreliable. Someone on here had a good suggestion for me when I was having starting issues, to temporarily install a clear hose in place of the return line on the injection pump to see if I had any air in the system. Also how old is your lift pump? perhaps it's going bad, weak or leaking.

 

[dependable]

I agree, check the lift pump and filter base first. But it could be the IP.

 

[fitz]

Would a bad IP cause air problems upstream at the fuel filter base?
I would guess that the air is coming from a rubber line, the fuel filter base, or the lift pump.

 

[antennaclimber]

I had a M1009 that had a similar issue. I finally found the drain plug on the bottom of the fuel filter base was not completely tight.
After tightening it the stalling issue never happened again.

 

[cucvrus]

OK I want to give an update. The fuel filter is over pressurized to the point that when it was removed it sprayed fuel all over the engine. So I see that as telling me it has no leaks in the fuel filter base or fuel supply system. Unless I am missing something. I am now at the point where I will need to change the injection pump regardless of my diagnosis. One of the 10/24 screws broke off in the housing. This happened when removing the top cover of the injection pump. Seems to be a common thing. This is the original injection pump with 29 years and 122K miles on it. So with that said no loss. The fuel tank was out last summer and cleaned and the sock serviced. I am going to rule that out for now. I am also going to replace the lift pump it is 5 years old. But appears wet at the the seam. The amount of fuel that sprayed the engine it is no wonder. But that is an easy inexpensive fix. The seam of the fuel pump looks like it own source of wetness. Not a result of the fuel spray. Any other ideas?

 

[cucvrus]

I had a M1009 that had a similar issue. I finally found the drain plug on the bottom of the fuel filter base was not completely tight.
After tightening it the stalling issue never happened again.

Well after all this and all the frustration that was lose. I will attempt to get the broken screw out but will probably just change the injection pump. I have the intake off at this point.I am half way there. I have a pump so what the heck change it.

 

[AECS]

If you keep having to bleed the filter you are getting air in there. You need to find the leak in your fuel lines.

 

[cucvrus]

I am saying that the bottom drain plug was loose. Who would have thought. Oh well I am never above learning. I bet I will check that next time. Now I have a broken screw to deal with.

 

[cucvrus]

OK that was not the problem. I did turn the drain slightly but upon further diagnosis and research we found the issue. We changed the motor mounts last week and disturbed the feed hose on the fuel pump. We removed the fuel hose and made a new one and loomed it and tied it securely to the frame. We changed the injection pump and the CDR valve. I runs really good now. But it does have more of a diesel sound like the timing is advanced. It is a HMMWV injection pump if that makes any difference. We used the top cover from the CUCV injection pump. It seems to run stronger.I only had the shift modulator on for 6 months and already some type of silk worm is making a nest it it.

 

[cucvrus]

I have a question. When I start this M1009 cold the engine races until the fast idle kicks down. It never done that before with the CUCV injection pump. Is the pump different? I am talking it kicks to 2 K rpm when it starts. I cleaned the fast idle solenoid but that seems to be the issue. It never done it on the other pump. We had to use the CUCV top cover on the HMMWV pump. Also are the nozzles different on the HMMWV vs the CUCV? I have 8 HMMWV nozzles I am going to install. The truck runs fine other then the cold start issue and the loud clatter from the nozzles when you accelerate. Any ideas if the nozzles are different? And is it possible that the HMMWV pump makes the M1009 truck seem more powerful? All this work for the sake of a rubbed fuel feed hose and a broken 10/24 screw on the injection pump.