Trying to verify bad CPS

Discussion in '94-97 PowerStroke Engine, Drivetrain & Chassis' started by lotzagoodstuff, Feb 3, 2019.

  1. lotzagoodstuff

    lotzagoodstuff SDD Junior Member

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    Truck shuts off very randomly. It will start again, even without cycling the key, and sometimes it seems to do the same thing 5-7 times in a row, sometimes it won't do it again no matter how far I drive it. It should be noted: it never seems to do it cold. I did pull the trouble codes and I did have a P0344, which makes me believe I need to change the CPS (I think mine might be original at over 100K mileage).

    I have Forscan and an OBD dongle, and I managed to capture the stalling after a 25 minute warm up. I can post a screen shot, but right from the get go the CMPLev is "low" and remains that way from key on to stall to starting again conditions. the CMPStat says "OK" the whole time. I feel pretty certain that it's the CPS that's giving me this issue, but I've not heard of a lot that were erratic.

    I spend most of my time over at OilBurners as I'm a former IDI owner, but I upgraded some time ago to a 1995 F350 CC DRW.

    Any input is appreciated, I can and will post
     
  2. 79jasper

    79jasper Full Access Member

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    Just change it, they don't always quit completely.

    Sent from my SM-N960U using Tapatalk
     
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  3. lotzagoodstuff

    lotzagoodstuff SDD Junior Member

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    Just posting this in case I can help somebody else with a similar situation.

    After removing the chip, changing the CPS, spending a little time using Forscan but not finding anything significant with respect to codes or suspect measurements, I remembered that my truck did some really odd power loss stuff, as in the radio would lose power and/or it would have all the start up lights stay on after the truck was running. I did some digging on other forums and realized the mechanical ignition switch could be the culprit. I changed it (super easy job by the way, 5 fasteners total, all pretty easy to access) and the truck hasn't died since.

    As the saying goes: it's almost always something really small and overlooked that makes you chase your tail the most.
     

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