Engine Quit

Discussion in '6.9L IH & 7.3L IDI Diesels' started by icanfixall, Sep 13, 2017.

  1. icanfixall

    icanfixall Official GMM hand model

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    :(Well today I drove off just fine. Then came home to get some stuff.Engine started right up and died. Cranked fine but no start.No stumble. Heard electric fuel pump running. Key on pulled fuel shutoff wire.. nothing.. No click. Made jumper wire from battery positive and cranked up to start. Ran fine.. So this now has happened twice. First time it burned a fuesable link behind the passenger side battery. This power to injection pump powers the water in fuel switch. the fast idle and the fuel shutoff solenoid. Also it powers the fuel filter heater but thats no longer connected. Any ideas whats overloading the system? My guess is the shutoff solenoid. any guess???
     
  2. vegas39

    vegas39 Full Access Member

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    Unless it's just a bad wire? My last truck did that and the wire had come undone in the loom a few inches away where it branches off somewhere else.
    It was a biatch peeling that strange braided outer core off to get to the connector where they were crimped together
     
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  3. pelky350

    pelky350 Full Access Member

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    Mine burnt a wire near the harness where it all connnecyd to the motor, like where the power for the glow plugs goes in, this is what caused my problems I'd check there for bad connections/ shorts maybe. Mines now all ran off switches thought because my harness was toasted fuel/advance/ plugs/ idle
     
  4. Thewespaul

    Thewespaul Supporting Member Supporting Member

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    If that's the only electrical issue you are having I might be tempted to just wire a separate wire for the fuel shutoff and just have a switch under the dash to turn it on. It's good security too.
     
  5. icanfixall

    icanfixall Official GMM hand model

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    Well spend a couple of hours taking off the wire loom jacket mess. Not fun for the age and not nicking wires is ruff. Sad part is the main engine wire harness plug has good power to a couple of pins but one barley lights up the test light. Trying to "find" the interuption of power is a mess because the wire size and color changes. So without a wire harness scamatic this job will be piece by piece till I find the problem. Did I say how much I hate electrical issues...
    On another note for a long time at night I can see my headlights dim... then come back to "normal" brightness.Been all thru the alternator and nothing wrong. I trust the electrical mom n pop shop to tell me this.
     
  6. laserjock

    laserjock Rebuilding! Supporting Member

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    Gary I had a fusible link wire drive me crazy. It was almost broke in two. Chasing with a volt meter the wires would check out until you would load the circuit then the voltage would drop to zero. Kinda sounds like what you might have going on.
     
  7. rhkcommander

    rhkcommander Full Access Member

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    Like the others have said, sounds like a wire bit the dust. You can poke the test light through the insulation if you wanted to cheat a bit, but you'll need to seal up that pinhole if its ok :angel:
     
  8. madpogue

    madpogue Full Access Member

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    Ignition switch?
     
  9. oregon96psd

    oregon96psd Full Access Member

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    Meet your new best friend lol. The ball goes on the inside of the loom so it doesnt cut the wire, then you just push it through the loom, you can strip the whole thing in seconds.

    IMG_0774.jpg
     
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  10. icanfixall

    icanfixall Official GMM hand model

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    This is a GREAT tool for stripping the electrical tape off the wire loom. Thanks for sharing this. Think I will get this from the wifes sewing kit...
     
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  11. laserjock

    laserjock Rebuilding! Supporting Member

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    That is an awesome idea!!
     
  12. Fixnstuff

    Fixnstuff Full Access Member

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    Gary, if you haven't solved the problem yet:

    I think laserjock's advice is right on track to locating the problem which will be on the Starter Relay side of the main 8-pin GP Harness Connector. I have a 1987 GP harness (engine side and starter relay/main harness side) mostly unwrapped on the floor near my desk so I can refer to that. It should be very close to or identical to yours with possibly a different wire color somewhere.

    There are two 20 ga. fusible links which are both in the power circuit to the components you mentioned where you are having the problem. Both of those Fusible links are spliced into a single red power wire that supplies the voltage through the 2 fusible links to the components you named, plus some others in the GP harness. Since other components are working one of those fusible links must be supplying voltage to() the FSS and that's where the problem will be. I'll look at the harness I have more closely after I post this and come back and tell you exactly which of the two fuse links goes to the FSS in case you can't see the defect but you probably will. I'll tell you exactly where to look.

    On the Starter Relay side of the 8-pin connector there will be 2 DARK BLUE wires (which identify 20 ga. Fuse Links) and then 5 inches further back on each wire should be a larger moulded black cylindrical shape piece with a flat side where the identification reads "FUSIBLE LINK 20 GA." for each one. The wires change color on the other side of the molded parts to RED/LIGHT GREEN tracer (stripe) Or one of them might be only RED).

    From the center of those moulded parts going back another 5 inches is where BOTH of the Red/Light Green stripe wires (or one of them red if that's the case) are spliced into one single larger RED power wire. That RED power wire comes out of the main engine compartment harness next to the passenger side battery. It comes from the Ignition circuit in the cab and that's what powers the components you mentioned and few others. That larger RED power wire does not connect to the Starter Relay (SR) but it runs in the same loom as the wires that run from the (+) post of the SR and go to the 8- pin GP harness connector.

    So, you'll simply need to remove the plastic conduit and tape from the harness on SR side of the 8 pin GP harness connector far enough back to inspect the fuse link wires and back 10 inches to the splice if you need to replace it.

    I have a few things to do outside (rain coming coming in tonight) and after that I'll look at the harness I have and figure out which of the 2 Fuse Links goes to the FSS.
     
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  13. icanfixall

    icanfixall Official GMM hand model

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    Thanks for the above post on wire colors and fuseable links. Last night I purchased the seam ripper so I'm going in soon.. Just kind of tired today and working on some electrical issues has never been my best suite even on my best days. But its not getting done sitting there either.Sure glad I have a spare driver.
     
  14. icanfixall

    icanfixall Official GMM hand model

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    Well it runs... But I have NO IDEA what I did...Damn worst kind of electrical issue is one you fix but have no idea what you did. I cut away much of the electrical tape from the injection pump back to the cold advance fast idle switch behind the thermostat housing. Then i cut away the tape to that small black box thing. So I moved something and made a better connection. Too tired to work on it any longer today. Maybe tomorrow I will feel like getting into this deeper. BTW I hear no "click" from the shutoff solenoid. I do have a couple of spare injection pumps and may swap the top housing with the shutoff advance solenoid in it. See if that might be my original issue. Some time back I replaced the feed wire to the glow plug solenoid with some 6 gauge speaker wire. I also installed a inline fuse at 20 amps to the solenoid. Not on the power feed wire. That blew when all this started too. So I increased the fuse to 25 amps and ita holding. The wire its designed to protect is heavy.I think its 12 gauge. Just do not recall. Did I say I hate electrical and REALLY hate intermittent electrical issues...
     
  15. laserjock

    laserjock Rebuilding! Supporting Member

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    Yeah intermittent issues suck for sure. That's the problem. Just carry a jumper wire or two with you until you can dig into it thoroughly.
     
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