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The diesel mechanic didn't do crap!!! Still hard starting!!!!!!

Discussion in '1982-Present GM Diesel' started by 84CUCV, Jan 31, 2003.

  1. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    The diesel mechanic didn\'t do crap!!! Still hard starting!!!!!!

    My 6.2 has new 13Gs in it. It was cold and I was all out of patents. So, I took it to a pro shop. (that is what they say they are anyway) What he did is he got rid of the resister on the fire wall. Now it starts much better. now, I am confused! 13Gs are 12v. Or so I thought. I put 13Gs in my fathers M1008 and it is fine with no problems. Can someone for the last time PLEASE explain these damn things to me. /forums/images/graemlins/1zhelp.gif

    Thanks Mike
     
  2. Tybee

    Tybee 1/2 ton status

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    Re: One more time....Need help with GP again and again

    I believe the glow plug system is 12 volts on cucvs
     
  3. DieselDan

    DieselDan 1/2 ton status

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    Re: One more time....Need help with GP again and again

    In a nutshell:

    Only the starter, Glow Plugs*, slave receptical (and radio power) are 24V. Everything else is 12V. The CUCV takes 24V from both batteries and through the use of the ballast resistors, drops this voltage back to 12V. If there is no load on the resistors (the GP are switched OFF - you will measure the full 24V after the resistors. This is how to quickly check the health of the system - check the voltage going in and out of the relay as it cycles. INPUT should be 24V=OFF then 12V=ON, OUTPUT should be 0v=OFF then 12V=ON.

    This is the Achilles heel of the system. If all 8 GP are NOT functioning, very soon you will have 8 <font color="red"> dead </font color> GPs. IE. loose one GP and the rest now recieve 13.5+/-V, drop another and you up to 15V, then 16.5, by now all are probably croaked.

    The GP are controlled by a temperature switch on the intake manifold, driver side. This signal goes to the Controll Card under the dash (look directly up from the brake pedal, small black plastic box). The Card itself is removable, some of the earlier versions would burn out (you could see the burn mark). But they all can fail. The Controller Card (which is 12V) switches the solenoid/relay ON/OFF (24V-&gt;12V).

    It really isn't that hard, but I would be EXTREMELY concerned about a civilian garage messing with it. The CUCV gp system was unique to the CUCV (no civilian model used that card or GPs, only the temperature switch is the same). If he just ran 12V from one battery (bypassing the resistors) I would think you would be putting alot of load on just the one battery. You could probably get away with it for a while, long if you rotated the batteries every month or so. /forums/images/graemlins/wink.gif
     
  4. Tybee

    Tybee 1/2 ton status

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    Re: One more time....Need help with GP again and again

    Sounds easier to switch to 12 volts for everything! Less complicated.
     
  5. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    Re: One more time....Need help with GP again and again

    DD, the 13Gs are 12 volt then right? What he told me is wrong. What are the 60Gs? I am tired of messing with this i am going to go 12 volt. Thanks again Mike
     
  6. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    Re: One more time....Need help with GP again and again

    How do I check the resister to make sure it is good? Now, there is a new resister, gp, relay, and the card under the dash. When I went to start it same thing all over again!! Could it be timing? How do I check the fuel system for a leak? Thanks from a very irritated person!
     
  7. DieselDan

    DieselDan 1/2 ton status

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    Re: One more time....Need help with GP again and again

    Yes the 13G are 12V, that's why you have resistors. I dont know about the 60G ( I would assume they are 12V PTC or Positive Temperature Control). When your "diesel" mechanic bypassed the resistors did he run power from just one (just 12V) battery. If he didn't your GPs are now burnt out. Ya it probably started great a FEW times.

    Look, go back to what I told you before and check the voltage going into and out of the solenoid as it cycles. Put the + probe to the terminal(s), - to chassis ground. And test the fricken voltage. It's pretty easy to test the health of your GP sytem with a voltmeter, you don't have to disconnect a thing. I want to help, but you've ignored my advise or don't understand what I saying, and caused yourself alot of aggrivation.
    Resistance between both resistors together (IIRC) is .28 ohms. DISCONNECT the resistors before you test them.

    post edited to not make myself sound like a total ass
     
  8. imiceman44

    imiceman44 1 ton status

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    Re: One more time....Need help with GP again and again

    You're right Dan.
    He most probably will have if not already toasted GPs.
    And don't worry about sounding like a Total ass, you ARE doing your best in giving the advise, and if someone doesn't listen or don't understand because they don't have enough background and experience then it's their problem.
    And this is in no way insulting you CUCV.
    It's just obvious you didn't know enough and you trusted a PRO MECHANIC.
    That is what got me started in my DIY.
    I got screwed by mechanics a few times untill I realized, they are not pro, just pro asses /forums/images/graemlins/grin.gif
    Live and Learn
    /forums/images/graemlins/thumb.gif
     
  9. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Re: One more time....Need help with GP again and again

    </font><blockquote><font class="small">In reply to:</font><hr />
    just pro asses

    [/ QUOTE ]

    That's funny but sad. I'm sure there are good tech's out there and many visit this board. What is too bad is that they are not the majority! After getting screwed over a few times I began doing every repair I could and the ones I'm unsure of I research and then make an attempt.

    I haven't been to a mechanic in 6 years now...

    Rene
     
  10. imiceman44

    imiceman44 1 ton status

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    Re: One more time....Need help with GP again and again

    20 years for me. /forums/images/graemlins/thumb.gif
     
  11. OFFRDK5

    OFFRDK5 1/2 ton status Premium Member

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    Re: One more time....Need help with GP again and again

    I take my K5 to the dealer to get the oil changed. Fer $10 bucks I couldn't resist. Who wants to lay out in the cold snow and change black Diesel oil? I take my own oil and my own filter so I know they are using what I want. They lube the thing up and get all dirty. Other than that....its been a while.
     
  12. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    Re: One more time....Need help with GP again and again

    Dieseldan, I figured what he did was wrong. The gp getting a full 24v did not seem to be a good thing. I talked with the mechanic the other day and he is not to bad after all. He gave me 40 bucks back, because he did not figure it out. that was the last thing I expected. I got lucky I put the resister back on and tested the gp. They are still good. I will be testing it soon. This is how it was put to me. I know some things about my truck. To do some work and save a few bucks, but I also can get myself in trouble. I agree with that. Still have a lot to learn. /forums/images/graemlins/grin.gif You guys on here know more then the guys around here. Thats why I always ask all these dumb questions. On the other hand that is how I am learning. Thanks again Mike
    One more thing what was the thing DD about the fuel filter base leaking?
     
  13. DieselDan

    DieselDan 1/2 ton status

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    Re: One more time....Need help with GP again and again

    The fuel filter base can leak air (into the fuel); never saw one leak fuel. But if you're smoking when it's trying to start you probably don't have a air leak (lost prime).

    I'ld be VERY surprised to find your glow plugs still good after getting straight 24V! I think your mechanic is getting off cheap (13Gs aren't cheap /forums/images/graemlins/smirk.gif )
     

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