Injection pump

Hello,
The 1986 M1008 I have starts then dies after a 3 day sitting. It will start up and run for a second and then die. It will then crank and crank and be hard to restart. i suspect the injection pump is sucking air. I have checked the mechanical fuel pump for bleed down, the rubber fuel return lines and caps, all seem ok. Anyone have a similar problem with the injection pump? I convert these trucks into wildland fire trucks. We have a endless supply of them. I am new to the 6.2L diesel. Thanks

It could also be the small mechanical fuel pump that is located on the passenger side of the engine below the exhaust manifold on the side on the block.
Mine had a small issue with hard starts, so the first thing that i replaced was the pump (its called the lift pump).
It only costs about $15 so even if it ends up not being the problem its not a big waste of cash.
The lift pump is driven by a metal pin that rides a lobe on the cam, When you remove the pump try to get something in between it and the steel plate on the block.
If you don't then you will have to get something very thin to pry it up enought to get you finger on it and push it all of the way up, Use some heavy grease (good wheel bearing grease works well) to hold the pin up while you get the new pump in place.
The rear bolt is a pain to line up so do it first, I learned that one the hard way and had to take it off and start again.

I recommend that you look online for the GM Tech Manuals for the 6.2L, They are loads better than any of the aftermarket manuals.

Thanks I will check it out.

One of the most common problems with air leaks on the CUCV's is the fuel pressure sensor in the bottom of the fuel filter. It has been said you can take it out, and plug it with something, but most find it easier to just replace.

Another good resource for the 6.2 is www.thedieselplace.com Tons of very helpful 6.2 owners over there.

Yes, sounds like you are loosing prime.

just wonder if anyone can help me locate part numbers for the waterseperator or parts for it. it leaks from the rear around either the fuel pressure sw or the water in fuel sw. have tried to find parts at a dealer put the parts they give me are to small. want to stay with what comes with the cucv. if anyone can help please post a response. thank you