M1008 cranks but won't start unless I ...

[Ackevor]

I tested the GP system; all wires from relay are providing equal voltage from its dedicated wire to each GP spade. Using the test light method touching the spade of each GP and +12V, each one lit up. On my ohm meter, it gives me 1-1.5 ohms from GP spade to threaded body. The voltage comes on with key in run and goes off when the wait light goes out as it should when connected to GP spade and ground. Under load each GP is getting 8 volts. I thought it was low but just to be sure I used a jumper from the engine ground and hooked up the GP to its dedicated wire and turned the key to run. It got hot and fast so I turned it back off then reinstalled.

I get fuel from the filter bleeder when cranking in a solid stream, so the mechanical lift pump is good. Removing/reinstalling the pink/red wire from the IP makes and audible click when key is in the run position (I unhooked the GP relay for this to keep GP's from burning up).

Just in case the newer filter was clogged I put a new spare in, bled air out until solid fuel came from the bleeder hose, and tried to start again. No luck. It doesn’t even seem like it’s trying to fire, just turns over.

I pulled a plug, disconnected the GP relay and cranked away to see if fuel sprayed out. While it was hard to get a good look from leaning out of the cab, I did not see any evidence of fuel.

I suppose cracking the Injector lines at the injectors with plugs removed and cranking the engine is my next step to see if fuel is getting there? I’m afraid to break the lines; they have probably been secured for 30 years now but look healthy as in not rusted. I will also put a clear line on the IP to check for air. Its just so odd the truck goes from starting good and running great to not at all...

 

[Phillip724]

I just purchased and m1008. And I will not fire. Even on a scary amount of starting fluid. The glow plugs are all bad at the moment

 

[dependable]

Count yourself lucky it did not fire w "scary amount of starting fluid" , if it had, the engine would likely be ruined.

 

[ezgn]

Count yourself lucky it did not fire w "scary amount of starting fluid" , if it had, the engine would likely be ruined.

Sounds like a fuel problem for sure. The fact that it runs and starts after finally getting it started makes me think your having a leak down on fuel after it sits. Have you checked your fuel lines leading into your tank. I believe they are 3/8'' and 1/4'' fuel lines. Make sure all your return fuel lines are dry and not leaking. Even a slight leak in a return fuel line can allow air into your lines.

 

[dependable]

If glow plugs had been working at all, the starting fluid would have pre detonated, causing damage to rings and has even been known to blow out the pressed in insert the injector is screwed into.

Edit: I see now post #22 is attached to a zombie thread. Advise poster Phillip to start their own thread w details of specific truck.