m818 will not fire up when cranking over, fuel problem?

[Blythewoodjoe]

Ok, here we go. I have searched and can't find the problem. So here's what happened:
truck has been hard to get cranked for a while. The last time I had it cranked it ran for about 30 seconds and died. It is not uncommon for it to do that. Tried to fire it back up and no fire at all. Have been trying to crank it for weeks. Has not attempted to fire up at all.
I my first thought was to look for a fuel leak. My old M813 had a leak and it was almost impossible to crank until I found the leak. I found the leak in the M813 years ago by putting a little air pressure on the fuel tank. I did the same here and it will push fuel out of the big line (supply line I assume) on the pump. With everything hooked up it leaks no fuel anywhere. I tried to use the cold weather starter in the cab but will leak fuel if you pump it up, but it does not leak fuel with a little pressure on the tank. I removed the selinoid from the fuel shut off only to discover it was nothing like what I thought it would be. I put it back together and gave up. I know a lot about a deuce multi fuel engines but this cummins has me lost. In fact I can't find the injectors. Help.
Thanks

 

[Warthog]

It is more than likely sucking air at the fuel hoses going to the selector valve. There is a sticky covering how to replace them.

Been there done that.

 

[Blythewoodjoe]

It is more than likely sucking air at the fuel hoses going to the selector valve. There is a sticky covering how to replace them.

Should have mentioned I removed one of the tanks and piped the other tank directly into the fuel filter a couple years ago. I forgot to mention the modification.

 

[jasonjc]

On mine the steel line in the tank had small rust holes. Putting air to the tank would get it started. You mite check that.

 

[Blythewoodjoe]

On mine the steel line in the tank had small rust holes. Putting air to the tank would get it started. You mite check that.

I thought about that but with air on the tank it pushes fuel out of the line at the pump. No air in the line, just fuel. I tried to crank it with air pressure on the tank too and still no go.

 

[jasonjc]

Is the emg shut off open?? You have manually reopen it if the handle has been pulled.

 

[74M35A2]

Maybe it is not a fuel issue? Will it fire with starting fluid? The injectors are under the valve cover, and rocker arm actuated. At the point you are, I would run a line to an external electric pump and a bucket of diesel, and see if it will run that way. This may be a good start for quick diagnostic review of the Cummins PT fuel system: http://oregonfuelinjection.com/pdf/cummins-pt-pump-diagnostic.pdf

 

[Floridianson]

Do the thumb screw thing.

 

[gimpyrobb]

Joe, if nothing mentioned works, swap out the fuel line that goes from the filter in the wheel-well to the IP. I work for a guy that will not even try to start a truck till that line is swapped(when picking up unknown trucks).

 

[ClintA]

Might try and take a little funnel and take the fuel line off at the PT and pour diesel down the hose until you hear fuel running in the tank, that has worked for me before. Also there is a plug on top of PT you can take that out and pour fuel in it to help prime system. hope this helps?

 

[WillWagner]

PT pump/system is self priming. No need to fill lines, install a lift pump. get a section of clear hose and run it from a clean bucket of fuel directly to the inlet of the pump. Crank it and watch the fuel suck up the line. Very shortly after it gets into the pump it will light. If no fuel is sucked into the line and the manual shut off is open, try turning the knurled screw on the front side of the FSOV in. if it still draws no fuel, remove the return line from the gear pump and crank it. if no fuel there, the gear pump took a dump.

 

[Blythewoodjoe]

Thanks for all the ideas. I actually got the truck crank a little bit ago. Here's what happened. It would fire off with ether with no trouble. But would still not attempt to fire off on its own. I put air pressure back on the fuel tank but this time much higher then the other day. Probably 5 to 8 PSI. Still no sign of leaks. The manual shutoff was in the open position to. I started cranking it with this air pressure on it and it fired up after about 15 seconds. It is still sluggish to rev up but it ran fine and I drove it around the block. I will try to crank it tomorrow without the air pressure. Also I must have messed up a solenoid only shut off. It does not shut off when there's no power to it now. I had to use the emergency shut-off. I guess I just need to get a new solenoid setup. Any thoughts on taking that apart again and attempting to put it back together? I think I will change some filters immediately also. I will post results tomorrow. Thanks for all the input.

 

[WillWagner]

Two ways to take the FSOV off. 1) remove the 2, 1/4 inch allens, #12 in the pic, that hold the assembly to the pump body. The outlet fuel line and wire need to be removed to do this. 2), remove the 4, 10-24 screws that hold the coil onto the FSOV, #7 in the pic.

Pros for removing the FSOV assy, the fillister screws, #7, can be VERY tight and the bottom inside one can be difficult to get at.
Cons, the 2, 1/4 in allens, #12, can be VERY difficult to get out, steel into aluminum, IF you strip/round out the allen hole out, you will be removing the pump to drill the head off to remove the FSOV

Pros for removing just the coil, no messing with a possibly frozen/stuck fuel outlet line, only removing 1 wire and 4 screws.
Cons, those little fillister headded bastardos can be a bitch to remove especially if they were tight and removed once before and re installed with a damaged drive edge in the screw slot. The bottom inside screw can be difficult to start back in the hole. more of a chance of the seal ring slipping out of the groove in the FSOV housing when assembling.

IIRC the fillister screws are 10-24. try and find allen screws to repolace them with, it makes reinstalling and servicing much easier. Used a dab of clean grease in the o-ring groove in the FSOV housing to hold the ring in place when assembling, the o-ring isn't, it is a square cut or quad ring.

Find these to replace the screws, http://www.mcmaster.com/#91251a245/=124enjl


The attached image is from the parts manual. A pdf copy is in the stickies, this is page 32. You can see it better in the manual.

 

[Floridianson]

I found a bad ground to be my problem with the FSOV. Hope you get it figured.