5.9 randomly loses power and shuts off

H Olson

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I have a 5.9 in a 94 2500 with 384k miles, stock with the exception of bigger injectors and Airfilter. I have had zero issues in the 4 years I have had it, servicing is mostly on time with quality oil. Every tank gets fuel treatment so I don't believe that is the issue. The problem is it will randomly shut off and then will restart, it is getting worse and it will also lose power after getting up to temperature in 3rd and O/D.
 

Philip1

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I would check your fuel pressure and see if either the lift pump, overflow valve or air intrusion causing issues. My dad had a similar issue with the lack of power and it was a bad overflow and a loose hose clamp going into the lift pump.
 

idiTravelAll

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Yep mines been acting up, relay for fuel shutoff solenoid.. been tying it up and untying to shutdown.. tried to install a manual cable (planned to but wanted to wait until after I make a new dash) my darn FSS 8mm bolts do not want to move and its helluva tight spot after the conversion.

EDIT: if you remove the FSS relay and stick a paper clip in the 2 prongs you should hear a solid click from your FSS.. be sure to remove paperclip ASAP or its going to change colors in your hands (bright orange)
 

irhunter

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I agree..."randomly shut off" sounds like an intermittent FSS issue. I have, on occasion, wired in a temporary indicator light. I pick up the power right at the FSS and have the light in the cab. The light is wired to glow whenever +12v is present at the FSS.

Roy
 

Olin Thomas

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Try stretching the overflow valve spring. My 1994 did the same type of thing and it was the overflow valve. The spring was weakened over time. I stretched the spring and it corrected the problem. Then I replaced the overflow valve.
 

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