Possible injection pump issues? Or other fuel issue?

[TexAndy]

I picked up an old forest service M35A2 at auction a little while ago. MkCoen was kind enough to help me tow it back to a friend's house nearby.

So I went to go work on it this weekend. Made sure the engine wasn't locked up and it had fluids.

Bled the lines to the fuel filters, then to the injection pump, then to the lines.

But I noticed when I got to the lines and cranked, it didn't spurt out like an arterial spray. Just kind of dribbled out of the lines in a weak flow.

The fuel cutoff lever moved freely.

It will crank all day long. Just refuses to start.

I did not tear into the hydraulic head. Wanted to ask here, first.

Will be going back next weekend armed with more knowledge, hopefully. I'm definitely going to look into the hydraulic head, but I'm thinking that if the fuel metering rod in the HH was stuck, it wouldn't be sending fuel to the lines at all, right? Or might it send some, but just weakly/not enough? I recall Texrdnec had issues with his hydraulic head, but I can't remember if he was getting not fuel to fuel lines or weak fuel to the fuel lines.

Could it be clogged fuel filters maybe? Or would that matter, since it's getting fuel to the injector pump?

Could it be O-ring issues in the hydraulic head or elsewhere in the IP?

Any ideas would be most appreciated.

 

[frank8003]

https://www.steelsoldiers.com/showthread.php?129033-Starting-issues-M35-A2

and put a gauge on the intank pump output at the top of the tank and/or at the filters to see what is going on.

 

[TexAndy]

In tank pump was dead. Well, fuse was blown and they had wrapped the fuse in foil. Voltage is getting to the fuse terminal. So the pump may or may not be dead, but it wasn't operating when I was trying to start the truck.

Reading the lds-465-1a troubleshooter, they do mention that it should read between 5 and 7 psi from the in tank pump. So perhaps it really does need a working in tank pump to start? This is the first time I've tried starting one without a working in tank pump, tho I've heard from others that it should start without it. Though maybe that was alot of people repeating incorrect info.

 

[gimpyrobb]

It is possible to run/start without the in tank, but if that isn't working, I'd start there.

 

[Welder1]

I would get the in-tank pump running and change all the filters. Then I would ensure a constant fuel supply to the hydraulic head. That will eliminate any issues up to the injection pump. If the fuel shut-off is free and still a no crank then you may have a hydraulic head issue. Eliminate all the easy stuff before you dive into the hydraulic head.




Eddie

 

[TexAndy]

I would get the in-tank pump running and change all the filters. Then I would ensure a constant fuel supply to the hydraulic head. That will eliminate any issues up to the injection pump. If the fuel shut-off is free and still a no crank then you may have a hydraulic head issue. Eliminate all the easy stuff before you dive into the hydraulic head.




Eddie

Yep, that's a good plan I can get behind. Got an in tank pump, primary and secondary fuel filters, and HH o-rings (just in case) on the way. Hopefully fuel filter change and tank pump replacement will fix it.