1986 M1008 w/ a 6.2L Diesel not starting

[Muddin_Maniac89]

has a brand new fuel tank and starter was just recently rebuilt. what are some of the reasons one of these wouldnt start. im a newbie to diesels.

[~Super~Midget~]

what does it do? will it turn over but not start? does it not make a sound when you turn the key? can we get some more details

[Quyonmob]

what does it do? will it turn over but not start? does it not make a sound when you turn the key? can we get some more details

^this.

Help us help you.

[CookieSoup]

dont you have to prime the fuel system? cause you can't just run a diesel out of gas and put more in and start it

[Muddin_Maniac89]

well i was told it cranks but doesnt fire. see i dont have the truck i my possession as of yet. i am just trying to troubleshoot right now. i know that'll probably piss you guys off but im trying to get info before i go tearing the truck apart when do get it.

[Quyonmob]

well i was told it cranks but doesnt fire. see i dont have the truck i my possession as of yet. i am just trying to troubleshoot right now. i know that'll probably piss you guys off but im trying to get info before i go tearing the truck apart when do get it.

You are trying to trouble shoot with only the information that it cranks but wont fire? Not a lot to work with.

[crossy's son]

It has a new fuel tank so chances are no one bled the fuel system out or "Primed" it

Get a new fuel filter, fill the fuel filter up with "PowerService" in the Grey bottle. Screw it on . Start it up and open the bleeder BEFORE it dies....It will run on the powerservice in the filter for quite a while allowing you time to let it get all the air out the system.

This is priming it...you're just filling the fuel filter with fuel so the engine has something to run off of.

[grayblazer]

Did the engine stop running after the fuel tank replacement? If so it's as above stated that nobody bled out the fuel system.

[Muddin_Maniac89]

yeah the guy replaced the fuel tank, injectors, and put a rebuilt starter in and she wouldnt fire he said. and guys im sorry im asking for advice without the truck in front of me but i wanna kno where to start when i do pick her up this week.

[LeoP]

All good advice above.

[Muddin_Maniac89]

***UPDATE***

well it turns out that the injector pump is pissing fluid as the motor cranks and it needs to be replaced. no idea on how to do this. anybody ever replace an Injector Pump on a 1986 6.2L diesel.

[Muddin_Maniac89]

*bump*

[Muddin_Maniac89]

*bump*

[jmack91z28]

Its a mechanical DB2. It runs off the timing chain gear so you have to pull the water pump and timing chain cover to unbolt the injection pump. You'll also have to take the intake manifold off to get to it. Engine should have a mechanical fuel pump on it, I'm not so sure your gonna have to prime it like previously stated. The fuel filter should also be a big rectangle filter mounted on the intake manifold, it shouldn't be a "screw" type like what comes on a dodge cummins. I don't know anything about this "Powerservice" stuff but just put diesel fuel in it. After replacing the injection pump it might airlock so you'll have to crank the engine with the fuel line disconnected from the injection pump so the mechanical pump will pull fuel up to the point of the injection pump.

Make sure you have someone with a good reputation rebuild the injection pump, have it done right and you'll never have to mess with it again.

This has a complete dissasembly diagram of the 6.2 and 6.5's. This should help out a lot, you might have to join this forum to view it though... http://www.thetruckstop.us/forum/showthread.php?25481-Military-Engine-Repair-Manual-6.2-L-and-6.5-L-Diesels

[LeoP]

No need to pull the water pump. You'll have to remove the oil fill tube, the intake,the injector lines, the three bolts that hold the gear on the pump and the three nuts that hold the pump to the housing. I can't remember if you need a gear puller to get the pump gear off the pump or not. It is quite a complicated job, if you don't think you can do it, get an experienced shop/person to do the job..You'll have to reprime the fuel system when completed. Assembly is the reverse of the above.

[Koots]

How did they test to see if the pump is putting out pressure?

If you just disconnect the injector fuel line, the pump won't build pressure in that line unless it's connected to an injector. I guess it needs the pintle resistance to build the pressure for each injector. Anyway, i just wanted to throw that out there just in case this is being done by people who aren't aware of these engines or diesels in general. They are weird but easy to work on once you figure them out...minus the fuel priming stuff. Before i switched to an electric lift pump, i was always afraid of doing anything with the fuel system on my truck. I could never ever bleed them properly without draining the batteries cranking and cranking to bleed the entire system.

Try pulling the glow plugs out and crank the engine over. see if the injectors are actually firing. Plus this helps spin the motor faster to help bleed air out of the lines too. Reinsert glow plugs and then try to start the motor once all injectors are firing.

[Koots]

Also, just for future reference seeing as how i dug up this thread...

These diesels need a lot of cranking speed and power to build up heat to fire. If you have a weak starting/battery system, have low compression or bad glowplugs...she won't start. Resist the urge to use starting fluid, use WD-40 instead.