M931A2 won't start

[mikey]

OK, I was driving my new M931A2 yesterday when it stalled. I was doing about 15mph in 1-3. After stalling, it refused to start. The starter was turning and the batteries were solid. It definitely seemed like a fuel issue. There was plenty of fuel in both tanks. Unfortunately, we had 10" of snow and this was a dangerous corner, so I had it immediately towed a few miles home.

I hit the TM's and read MANY threads. The TMs mention two issues that can cause a stall while driving, Emergency Stop Cable and Throttle Control Solenoid. I popped the hood today and I'm attaching pictures of what I THINK may be the issue. I have never seen a 939 engine before I bought this, and the TM diagrams as sketchy, or at least I have yet to find a detailed one, so it's hard for me to know how things "should" look.

Any and all help would be appreciated!

Thanks

Mikey

 

[Suprman]

Watch the motor while someone cranks it see if the fuel solenoid retracts. Did you by chance switch fuel tanks around the time it died? Have you changed the fuel filters and drained the water separator? Do you know how to prime it up?
Will

 

[mikey]

I did not switch tanks when it died or anytime within the last week. I did switch tanks a few times, since recovering it without issue. I did read the threads about cleaning the tank selector as that is known to let air in.

Step 1 for me was inspecting the emergency stop cable and the throttle solenoid. Step 2 will be checking the solenoid while cranking. I need solider B. I've read on here how to prime it, that would be step three. I have not changed the filters. That would be step four.

But the cable I'm holding, isnt that the emergency stop cable? Is it supposed to be hanging free there? It seems it should be connected to something. The metal from the cable itself has paint worn off by my thumb as if it was connected to something. Then again, having never seen a Cummins 8.3 before, I'm not sure how things should look.

Mikey

 

[Suprman]

The piece hanging free you are referring to appears to be correct. It is quite possible you sucked in air somewhere and lost prime. If you look on the forward back of the injector pump there is a bolt its a 10mm I think. Open it 2 turns no more or it will fall out. Press primer pump 100 times or until fuel comes out where the bolt you just loosened is. As soon as you see fuel, tighten bolt and try to start. If you want, before you do that drain the water separator by the air intake tube drivers wheel well area. Loosen the petcock on the bottom and then press the schrader valve on top. Then prime away. To check the starter solenoid if you are flexible, open front window all the way stick head out watch solenoid and see what happens.
Will

 

[doghead]

A look at the parts TMs might help. They are just pictures(exploded views) and part numbers.

 

[porkysplace]

That is the emergeny cable it should be hooked to the lever your fingers are on in picture #1.
Eke the stop off the cable feed through the small hole of the lever your index finger is on reinstall the cable stop and adjust.

 

[mikey]

That is the emergeny cable it should be hooked to the lever your fingers are on in picture #1.
Eke the stop off the cable feed through the small hole of the lever your index finger is on reinstall the cable stop and adjust.

Obviously that's not the current fuel issue, but yes, it looked like it should go through that hole. But of course, that just pulls the lever towards the driver, the position it is now, to stop fuel. But good to know it was "disabled" for some reason and I'll reconnect that while I'm under the hood.

 

[porkysplace]

Obviously that's not the current fuel issue, but yes, it looked like it should go through that hole. But of course, that just pulls the lever towards the driver, the position it is now, to stop fuel. But good to know it was "disabled" for some reason and I'll reconnect that while I'm under the hood.

If the lever is pulled toward the cab it needs to be reset.

 

[mikey]

The piece hanging free you are referring to appears to be correct. It is quite possible you sucked in air somewhere and lost prime. If you look on the forward back of the injector pump there is a bolt its a 10mm I think. Open it 2 turns no more or it will fall out. Press primer pump 100 times or until fuel comes out where the bolt you just loosened is. As soon as you see fuel, tighten bolt and try to start. If you want, before you do that drain the water separator by the air intake tube drivers wheel well area. Loosen the petcock on the bottom and then press the schrader valve on top. Then prime away. To check the starter solenoid if you are flexible, open front window all the way stick head out watch solenoid and see what happens.
Will

I've read A LOT of your posts regarding the 939, thanks!

I'll have soldier B tomorrow. I'll check the solenoid while starting, then drain the water separator. Then I'll prime the system and go from there.

Thank you!

Mikey

 

[doghead]

Or just reset the emergency shutoff lever(like PP suggested), and see if it starts up.

It should

 

[mikey]

Searching "emergency" in all three parts TM's produced only lights and couplings. I'll try other terms for the emergency stop cable. And I did just notice two more parts TM's for Depot Maintenance parts. I'll search those as well.

 

[mikey]

Or just reset the emergency shutoff lever(like PP suggested), and see if it starts up.

It should

That cable is disconnected, according to porky's first post. I'll find the instructions for resetting it and see if that helps.

Thanks

 

[73m819]

Just put your hand on the lever, move it towards the FRONT of the engine if it is back.

 

[porkysplace]

Post #13 will point you to the correct TM , if you look at the attachment. The TM number is on the top.
[h=1]Won't Shut down[/h]

 

[mikey]

Just put your hand on the lever, move it towards the FRONT of the engine if it is back.

Again, keeping in mind that I'm brand new to the 939, let me verify how I believe this works.

At rest, vehicle powered off, that lever SHOULD be to the rear of the truck, where it currently is. When cranking, the solenoid should close and the lever should open towards the front of the truck. If the emergency engine stop is pulled, it will not allow the lever to move to the front, even when cranking, and thus needs to be reset. Is that correct?

If that is correct, my emergency engine stop is not currently connected to anything so IT should not be an issue.

I will check with solder B tomorrow about whether or not the solenoid opens during cranking and whether or not the lever moves to the front of the truck if the solenoid does open.

I've read Sandcobra's post about the solenoid failing regularly on A2's. I'll confirm or rule the solenoid out tomorrow.

Thanks again!

Mikey

 

[porkysplace]

Again, keeping in mind that I'm brand new to the 939, let me verify how I believe this works.

At rest, vehicle powered off, that lever SHOULD be to the rear of the truck, where it currently is. When cranking, the solenoid should close and the lever should open towards the front of the truck. If the emergency engine stop is pulled, it will not allow the lever to move to the front, even when cranking, and thus needs to be reset. Is that correct?

If that is correct, my emergency engine stop is not currently connected to anything so IT should not be an issue.

I will check with solder B tomorrow about whether or not the solenoid opens during cranking and whether or not the lever moves to the front of the truck if the solenoid does open.

I've read Sandcobra's post about the solenoid failing regularly on A2's. I'll confirm or rule the solenoid out tomorrow.

Thanks again!

Mikey

The emergency shut off does just that , shuts the fuel off. Just because the cable isn't hooked up doesn't mean it did not move . The first thing you need to do is verify it is in the correct position to start the truck , then if that does not work move on to the electronic shut off . This is why you need to read the TM's and follow the troubleshooting section . Follow 73m819's directions and see if it will start .

 

[tobyS]

It's as Kawgomoo, 73M819 and porkyplace says. When the lever above the fuel pump is back it shuts the fuel off, when it is forward it opens the valve. This is just a mechanical valve. You also have the electric valve for normal (electric) operation from the dash.

One of mine came with the solenoid spring and a diaphram removed, thus that valve was open all the time and would not shut it off. They operated it entirely from the manual valve. It was a pain having to reset and took me a few days to work out, since it ran and did not shut down.

You will find it is a way to disable the truck so an average Joe can not just turn the switch and go. That's why it does not reset when one pushes the cab lever forward (if yours were hooked up). You could add a second stop to the cable and make it work both ways, but the military seems to like having that "secret" procedure. It makes all appear to be normal when the fuel is really shut off.

You probably have a shut off manual fuel valve. Push it forward and try.

 

[mikey]

Kawgomoo,

Excellent posts, thank you. The TM's are frustrating. Yeah, of course I'm reading them. But they don't have pictures, and many of the diagrams like the one PS linked above, must be from the Cummins 250 because it looks NOTHING like my fuel pump and solenoid on the 8.3. I provided pictures because I found something that does not look right. I still can't find the diagram for this in any TM (I'm sure it exists) that shows how it SHOULD look. Luckily I found a picture on the GL website.



I DO have a plan and I'm sticking to it, but sometimes experience from other 939 owners is substantially more valuable than info in the TM's.

This morning, I got in some brief troubleshooting before the gf had to go to work. I started by moving the lever as far towards the radiator as possible, then let it go. It obviously returned to the far rear. The GF cranked the engine and the solenoid retracted. The lever moved to the front. It did not start. I then held the lever towards the front while she cranked. No go.

Solenoid appears OK. Fuel pump shutoff does not appear to be the issue. Now I'll change filters and prime it. Unfortunately, the batteries are getting weak and the temp is 18f. She never did like starting below 40f, so I'll have to charge the batteries and wait for a warm spell.

Thanks to everyone so far.

Mikey

 

[Sephirothq]

Warm ether can be your friend. I heard that the A2 have 2 fuel filters. Do you know where they are and the part numbers? I might be headed into the same issues you currently have.

 

[tobyS]

Sorry, I was referring to the 250. Didn't see your reference to A2. My A2's seemed to take a lot of cranking too.