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Glow plug cycling

Discussion in '1982-Present GM Diesel' started by Tybee, Dec 9, 2001.

  1. Tybee

    Tybee 1/2 ton status

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    My glow plugs cycle real slow, light stays on alot longer during the cycle then it use to. I thought it was the batteries cause one was bad, I bought two new ones today and it still is slow. My voltage gage goes all the way down to about 8 volts. Im thinking it might be a ground issue. Any comments would be helpful.

    1984 GMC Jimmy 379 diesel, 700R4, 3.73s, 31x10.50 x 15
     
  2. surg82k5

    surg82k5 1/2 ton status

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    First of all let me tell you i am no expert on the 6.2 but I have one and know its characteristics. I think the glow plugs should stay on about 7sec when you first turn the key to on. once you start the engine they will continue to cycle even after the engine is running, mine sometimes stay on for 5 sec ata time but sometimes shorter. I think that the voltage going down.. means that well your glowplugs are working ok, they really do suck down the juice when they are all working so i think this about normal. My glowplugs sometimes come on even when the engine reaches about 200 Degrees. Now i don't know what that is all about or if that is normal but so far they still all work so until they start burning out i guess i will just go with it. hope this helps a bit or gets you some more responses.. if I can help just reply and I will get back to you
    Sergio

    Check out my new website. <a target="_blank" href=http://www.surg82k5.rockcrawler.com>http://www.surg82k5.rockcrawler.com</a>
     
  3. Tybee

    Tybee 1/2 ton status

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    All these things happened within the last month, ive had the truck for over a year now. Thanks foryour response.

    1984 GMC Jimmy 379 diesel, 700R4, 3.73s, 31x10.50 x 15
     
  4. DieselDan

    DieselDan 1/2 ton status

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    Up front - I have very little experience with the civilian GP controllers. But I have had to replace mine cause it wa freakin' out (buzzing, flashing-not cycling, etc.). The word is: use ONLY AC Delco controllers, the aftermarket replacements are crap.

    Real trucks don't have spark plugs!
     
  5. Tybee

    Tybee 1/2 ton status

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    At night I can see a slight glow from my glow plug light while driving, and its not from the dash lights. Isnt there a way to remove the controller and use a switch.

    1984 GMC Jimmy 379 diesel, 700R4, 3.73s, 31x10.50 x 15
     
  6. Tybee

    Tybee 1/2 ton status

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    The engine sometimes wont shut off after I turn the ignition off but then shuts off after a couple seconds. Could this be the shut off selenoid sticking. Anyone have this problem before and are they expensive?

    1984 GMC Jimmy 379 diesel, 700R4, 3.73s, 31x10.50 x 15
     
  7. DieselDan

    DieselDan 1/2 ton status

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    Wow Ty, the electrical gremlins are workin' over time. I think you have the earlier style GP controller that uses contact points (if not, the later style is in a gray plastic box mounted on the right/rear near the intake). If your GP light is glowing something is definately wrong. You might be able to clean up the contacts on the earlier style (the later style - just toss it).

    As far as your run-on problem, yup. The fuel solenoid should stop the engine instantly. It's pretty simple located under the cover on the top of the pump.

    Real trucks don't have spark plugs!
     
  8. surg82k5

    surg82k5 1/2 ton status

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    I know that you can put a switch on for the glowplugs. I have one on my blazer. The guy i bought it from put it on so i am not exactly sure what wires he used but i iknow that it cvan be done, and that it has saved me on several occasions when my glowplugs did not want to go on with the turn of the key,
    Sergio

    Check out my new website. <a target="_blank" href=http://www.surg82k5.rockcrawler.com>http://www.surg82k5.rockcrawler.com</a>
     
  9. Danno

    Danno 1/2 ton status

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    If you're going to replace the GP controller, have you considered upgrading to the newer style GP controller? If you're a member of http://www.thedieselpage.com, you can read a writeup someone did on this conversion.

    It's supposed to be cheaper than replacing the stock GP controller and relay, and more reliable.

    Also, if you want a hand sometime with your truck, let me know. I'm in Longmont.

    1984 K5 Blazer 4x4 Silverado
    6.2L diesel, 700R4, 3.42 gears, 31x10.5" tires
     
  10. Tybee

    Tybee 1/2 ton status

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    Yes, I am a member of the diesel page or was my membership expired last month. I dont wanna spend any real money on it. Maybe ill just look at the schematics and see if I can figure it out. Thanks all

    1984 GMC Jimmy 379 diesel, 700R4, 3.73s, 31x10.50 x 15
     

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