M1009 not holding fuel prime

[Farmboy0318]

I have an 85 M1009 with the 6.2 diesel. It runs and drives perfectly...when it starts. If it sits overnight, you have to cycle the glow plugs 2 to 3 times and most of the time gas rag it or give it a shot of the evil juice. Once it pops off it smokes like **** as it should and will run just fine. Get out of it and let it sit a couple hours, will fire right up after cycling the plugs twice. 8 or so hours and you are back to the gas rags and the juice. I have changed the fuel filter multiple times to no avail. I have looked for cracked fuel lines but cannot find anything that seems to be leaking. Is there a fuel supply pump in the tank or anything or is it just the injector pump on this unit? I am somewhat mechanically inclined but this has me stumped. Any help is greatly appreciated.

 

[porkysplace]

I have an 85 M1009 with the 6.2 diesel. It runs and drives perfectly...when it starts. If it sits overnight, you have to cycle the glow plugs 2 to 3 times and most of the time gas rag it or give it a shot of the evil juice. Once it pops off it smokes like **** as it should and will run just fine. Get out of it and let it sit a couple hours, will fire right up after cycling the plugs twice. 8 or so hours and you are back to the gas rags and the juice. I have changed the fuel filter multiple times to no avail. I have looked for cracked fuel lines but cannot find anything that seems to be leaking. Is there a fuel supply pump in the tank or anything or is it just the injector pump on this unit? I am somewhat mechanically inclined but this has me stumped. Any help is greatly appreciated.

Keep using ether and you will be replacing head gaskets or more. here is link to the helpful threads for the CUCV;

CUCV Helpful Threads

GLOW PLUG SYSTEM
GP Module Operation
http://www.steelsoldiers.com/showthr...y-of-Operation

GP Temperature Sensor
http://www.steelsoldiers.com/showthr...79-Temp-Sensor

GP Relay Repair
http://www.steelsoldiers.com/showthr...g-Relay-Repair

GP Resistor Bank Bypass
http://www.steelsoldiers.com/showthr...or-Bank-Bypass
http://www.steelsoldiers.com/showthr...s-a-GOOD-thing

Manual Glow Plug Switch
http://www.steelsoldiers.com/showthr...ow-Plug-Switch

There is a lift pump to get fuel to the IP. It could be the rubber lines , or the pick-up in the tank, cracked fuel filter base quite a few things to check when loosing prime.
this will give you a idea on the lift pump.

Fuel Lift Pump 1986 M1009


You can download the TM's here;
CUCV


M1008, M1009, M1010, M1028, etc...

How to use/read Technical Manuals

 

[Mainsail]

It doesn't necessarily need to be fuel leaking out, but air leaking in.

The next time you have it running, park it nose-down overnight and see if it starts easily the next day.

IF YES: You have air leaking in somewhere. My first guess would be the filter, which I had a problem with and fixed by doing a spin-on filter conversion. COST: $0.00
IF NO: Back to troubleshooting. Test your glow plugs first. COST: $0.00

Do the free stuff first.

 

[ssdvc]

What Mainsail said. I had the exact same issue and found a bad fitting (leaking air). Once fixed, she fired right up. I then had issues starting when it got cold out. Replaced my glow plugs and once again, she is going strong.

 

[johnjr]

You probably have some bad glow plugs.

 

[Recovry4x4]

I think I'm in a similar situation. I suspected glow plugs since my system was feeding them power. I replaced 7 (#8 might break, I'll fix it later). Still takes quite a bit of cranking and it shouldn't. Replacing my fuel filter assy with one of the Stand yes Gimpy was selling. Hoping for the best.

 

[sandcobra164]

My issue turned out to be the injection pump itself but had similar symptoms. I'm not saying that is your issue, I'd start with the basics as others have pointed out. The stock cartridge fuel filter base has a known leak location with a pretty simple fix. 3 options, (1) remove the fuel pressure sensor and plug the hole in the base, (2) replace with a civilian model base which does not have the fuel pressure sensor or (3) convert to a spin on style fuel filter base. A simple check would be to look at your passenger side frame rail and firewall. It doesn't take much of a leak to cause a loss of prime. I chose option 3 and still had an issue of losing prime. The original base did have a leak so I thought I was good to go but the issue remained.

Basics of the fuel system, diesel is pumped from the tank by a camshaft actuated lift pump similar to a small block Chevy on the passenger side of the block. Fuel from that point forward to the fuel filter and injection pump is under 5-8 psi. Like many diesels the lift pump provides much more diesel than needed and quite a bit is used for cooling of the injection pump and injectors and returned to the fuel tank.

 

[Recovry4x4]

Thanks Joseph. I have the filter setup (for years) so it's a no cost thing to install. I feared a pump as well so it this doesn't help, I'll look towards getting my IP remanned.

 

[cucvmule]

It doesn't necessarily need to be fuel leaking out, but air leaking in.

The next time you have it running, park it nose-down overnight and see if it starts easily the next day.

IF YES: You have air leaking in somewhere. My first guess would be the filter, which I had a problem with and fixed by doing a spin-on filter conversion. COST: $0.00
IF NO: Back to troubleshooting. Test your glow plugs first. COST: $0.00

Do the free stuff first.

Spot On

 

[cucvmule]

Welcome From Missouri!

Glow plugs, essential to startup. Easily checked, read the TM's.