Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Help with glow plugs needed...

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by rocko, Sep 18, 2002.

  1. rocko

    rocko 1/2 ton status

    Joined:
    Jul 3, 2000
    Posts:
    3,380
    Likes Received:
    0
    Location:
    Ellsworth, Maine
    I already posted this in the diesel forum but since this forum has higher traffic volume, I'm hoping someone here can help me out.

    In the '83, when I turn the ignition switch, the glow plugs light will not come on, no click, and it's not allowing the truck to start.

    Don't know if this matters, but yesterday after the truck started and ran fine, the light would come back on.

    Any ideas? I'm new to diesel and am clueless.
     
  2. heavy4x4

    heavy4x4 1/2 ton status

    Joined:
    Aug 28, 2002
    Posts:
    3,270
    Likes Received:
    0
    Location:
    Delafield, Wisconsin
    Since you're new to diesels, let me try and explain the mechanics of a diesel engine. First of all, there are no sparkplugs to ignite the fuel and air. In the combustion chamber, the piston compresses plain air (no fuel mixed in). This compression is very high. Something like 20:1 or 22:1 depending on the engine. Now, as air compresses, it heats up. So, once the air is fully compressed, fuel is injected into the combustion chamber and because of the heat of the compressed air, it ignites. That's pretty much the basics.
    Now, on to glow plugs. Glow plugs are used in the initial startup of a diesel engine. Because the air flowing into the cylinder is cold, when it compresses it sometimes doesn't become hot enough to efficiently ignite the fuel being injected in. So, a glow plug basically heats up the chamber a bit in order to allow the fuel/air to ignite.

    Now I have a question for you. When the light wouldn't come on and you said the truck wasn't allowed to start. What do you mean? Did the truck physically not start, or could you not turn the key - get any cranking? Most likely the glow plugs not lighting will have something to do with an electrical connection, but without knowing a little more, I can't help you much.

    Hope my info helps you understand what's happening, and if anything I said is wrong, please, someone correct me.
     
  3. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    The glow plugs have an electronic controller that determines when/if the plugs come on and how long they stay on. It's all based on the engine temp. The controller or the temp sensor could be hosed. A friend of mine had a 6.2 in an 81 or 82 pickup. His controller kept staying on too long and burning up his glow plugs (At around $20 each!). So he installed a push button switch on the dash to let him bypass the controller and control the glow plugs manually.
     
  4. 4x4dreamer

    4x4dreamer 1/2 ton status

    Joined:
    Jul 8, 2002
    Posts:
    874
    Likes Received:
    0
    Location:
    St. Petersburg, FL
    my 6.2 has a manual button. I was considering trying to fix it the way it was supposed to be, but then I talked to my uncle. He has been a long haul trucker for about 30 years, he says he used to have a manual controller on one of his rigs, and in the cold cold Michigan winters, when nobody else could start, he would just heat his plugs up hotter than anybody else could, then he'd fire right up. I was sold at that point.
     
  5. rocko

    rocko 1/2 ton status

    Joined:
    Jul 3, 2000
    Posts:
    3,380
    Likes Received:
    0
    Location:
    Ellsworth, Maine
    The key turned and did get cranking like it wanted to start but the glow plugs light never turned on and wouldn't let the truck fully start.
     
  6. fourwheelerjeff

    fourwheelerjeff 1/2 ton status Staff Member Moderator

    Joined:
    Nov 16, 2001
    Posts:
    3,419
    Likes Received:
    6
    Location:
    meadow, tx; in the boonies
    i left you a message on your post in the garage /forums/images/icons/smile.gif
     

Share This Page