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Fuel Issues - Fuel Cut Off Valve Solenoid?

1st Generation Dodge Cummins 89-93 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with Rotary Injection Pumps

Fuel Issues - Fuel Cut Off Valve Solenoid?

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Old 12-26-2018, 11:57 AM
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Default Fuel Issues - Fuel Cut Off Valve Solenoid?

I'm running a 1990 5.9L 1st gen Cummins that been having fuel issue of late. Three times now the engine loses power and sputters to a stop and won't restart. My only option has been to tow it to a mechanic. Here's what's been done to diagnose and potentially fix the problem so far.
  • Both filters (engine and secondary) replaced
  • Fuel pressure checked - nothing wrong
  • Fuel pump check - nothing wrong
  • Kink in fuel return hose found and repaired
  • Injector pump checked - nothing wrong (a 40HP fuel pin and 3200rpm governor spring were installed a while back)
Both of the mechanics who have looked at the engine and fuel system say that nothing they found would have caused the truck to stop working as it has. In other words, they don't know what's wrong and so now that the truck's running fine, I'm not comfortable taking it on long trips.

Having done some research on this, what makes the most sense is that the fuel cut-off valve, or the relay that controls it, is intermittently failing, stopping fuel from getting to the injector pump. As far as a know, the valve and relay are original to the engine which is now almost 30 years old.

Appreciate any feedback about what might be causing the fuel issues and/or best ways to see if indeed it's the valve.

Thanks,

Michael
 
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Old 01-20-2019, 02:04 PM
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Generally a fuel shut off solenoid won't give you a warning. It just quits. A quick remedy to this is to take off the solenoid, remove the plunger and spring and re install the solenoid. you will have to shut the engine off with the mechanical shutdown lever on the side of the injection pump. you can hook up a cable to the dashboard and just pull it out to shut down the engine. If you have a manual transmission it would be wise to use a locking type cable so you can lock it out. Otherwise, if you parked it in gear and someone bumped into it there's a possibility it would start and take off. Or you can park it in neutral if your parking brake works.
 
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Old 01-20-2019, 02:14 PM
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Forgot to mention that this effectively eliminates the solenoid and makes your fuel system completely mechanical so the engine will run with the key in the off position. If your truck still shuts off, you can rule out anything electrical I.E. fuel solenoid, relays and such. I would then look for maybe an obstruction in the fuel tank possibly blocking the pickup tube on occasion. Good luck.
 
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Old 01-20-2019, 02:16 PM
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Originally Posted by gafbag360 View Post
Generally a fuel shut off solenoid won't give you a warning. It just quits. A quick remedy to this is to take off the solenoid, remove the plunger and spring and re install the solenoid. you will have to shut the engine off with the mechanical shutdown lever on the side of the injection pump. you can hook up a cable to the dashboard and just pull it out to shut down the engine. If you have a manual transmission it would be wise to use a locking type cable so you can lock it out. Otherwise, if you parked it in gear and someone bumped into it there's a possibility it would start and take off. Or you can park it in neutral if your parking brake works.
Thanks for the feedback. I considered this by am not much of a fan of the manual shut off route. I did get a new solenoid and relay which I hope to install soon once the weather improves. Both are original and thus nearly 30 years old. Beyond that I can't find any other reason so far why the gine would just quick like that so I'm fairly confident that I'm on the right track.
 
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Old 01-20-2019, 02:31 PM
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Sounds like you have it under control. Been driving tractor trailer almost 37 years. At one time mechanical shutdown was all we had. I know the solenoid and relay are pretty short money so it can't hurt. Being 30 years old it is cheap insurance. This is why I stick with my 1st Gen. New ones might be nice and have all kinds of power but at what price? Don't need computers and sensors to get 23 mpg. 160 hp and 400 ft lbs it plenty for a daily driver and occasional work horse. Good luck.
 

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