The beast died after hitting a bump!!

[Brutacus]

Hey guys, I'm trying to trouble shoot this and get an idea where to start. My truck is a m818, with cummins NHC 250. I was driving the truck home from work, hit some bumpy train tracks and my truck died. It started up and I continued home. About 200 yards from home, the truck just died. The engine just puttered out. It started and died a few more times. When I started it the last few times, I could here the belts screeching, it has never do that before. Then just 75FT. from my driveway it died, and the started wouldn't even catch!! I ended up having to call a tow rig to get it in my drive way. Anyways, I trying to figure out where to start and I'm not sure. This is cooking my noodle. My first guess is the fuel system, but I'm not sure due to the fact that the truck died AFTER hard hitting some rough tracks. I'm open to any ideas where to start.

 

[roofconsult]

When the starter wouldn't work that seems to indicate a battery connection issue. Were your lights and gauges working?

 

[fsearls92]

Since the starter wouldn't catch once you got near your house maybe it jarred the batteries and something went wrong in the battery box (check cables and terminals). Might be a good place to start.

 

[Brutacus]

All the lights and gauges do work. It could be a lose wire on the starter, but if it is why would the engine die. Shouldn't the cummins keep running even without any power? Anyways I'm adding this to my check list.

 

[doghead]

It needs power for the fuel shutoff to keep it running.

 

[Brutacus]

I didn't know that. I thought they military diesel's could keep going without power. Anyways Like I said earlier, the starter did work, until I got close to the house. The solenoid doesn't even catch now. Does the solenoid/starter have a temperature protection built into it?

 

[simp5782]

I have had mine do the same thing after hitting bumps and die completely. Check your solenoid wire as it may have gotten old and crusty and just broke in the harness or at the solenoid. Make sure you have power getting to it.

I had an old m39 series truck mess up after bumps but i had alot of crap in the tanks and it got sucked up.

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[big block 88]

I didn't know that. I thought they military diesel's could keep going without power. Anyways Like I said earlier, the starter did work, until I got close to the house. The solenoid doesn't even catch now. Does the solenoid/starter have a temperature protection built into it?

they can run with absolutely no power from batteries. Just turn the screw on the shut off solenoid.

 

[gimpyrobb]

Check your batterys first, maybe the alt stopped charging.

 

[Nomadic]

All the lights and gauges do work. It could be a lose wire on the starter, but if it is why would the engine die. Shouldn't the cummins keep running even without any power? Anyways I'm adding this to my check list.

It could be more than one problem fuel starvation (as mentioned) and low voltage from the alternator. The belt screeching could be from the alternator pulley slipping. The alternator may have moved and caused slack in the belt or the bearing might be freezing up. What is the battery voltage?

 

[Brutacus]

I'll be checking that too. I won't be able to get a look at it until Sunday. I'll keep my results posted

 

[doghead]

Are your batteries secure?

 

[Brutacus]

My batteries are secure. All my lights come on, gauges work, etc. The only problem as stated, the belts started screeching, the engine wouldn't stay running, and then it wouldn't even turn over. Now one thing I was wondering about is, what if the ignition circuit has a loose wire/ground in it? With the batteries being fine, that would narrow it done some. This is my first diesel, so I'm still learning about it. I still haven't had a chance to climb up and check the alternator. Is it possible for the alternator to short out/reverse polarity? That happened to my 69 Superbee back in 2007 while driving down the highway. That caused me several headaches.

 

[162tcat]

If the belts are screeching, start there. Something is physically wrong for that to happen. Screeching belts isn't an electrical issue. Fix that problem first then tighten the thumbscrew on the fuel shut off and jump the starter. As long as it has fuel and enough power to turn over the starter it should run indefinitely at that point or until the fuel tank empties.


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[74M35A2]

Alt is probably out to lunch.

 

[Brutacus]

I got to get the beast running again before I check the belts. I'm hoping that jarring bump just knocked an adjustment bracket loose on the alt or something else. I'm hoping that is the only thing causing the belts screeching. I hate headaches...

 

[big block 88]

Why do u need it running to check the belts?

 

[Nomadic]

I got to get the beast running again before I check the belts. I'm hoping that jarring bump just knocked an adjustment bracket loose on the alt or something else. I'm hoping that is the only thing causing the belts screeching. I hate headaches...

Push on the belts with your finger to measure play. Measure from the resting point to the stop point (you don't need much finger force). Then check the spec to see how much play there should be. I don't know what the spec is, guessing less than an inch?

 

[Brutacus]

I was thinking I would have to have it running to just to see which belts are screeching. If my Alternator is out to lunch, then it would have to be running to check the gauge to see if it is charging. I'm going to check the tech manual.

 

[ross165123]

I had the same problem with mine on large bumps. It ended up being the wiring to the selinoid behind the dash was just old and had a bad contact. I'd start it up and do wiggle test on the wires under the dash.