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Shutting off in Drive in auto tranny?

Discussion in 'The Garage' started by 78Suburban, May 14, 2006.

  1. 78Suburban

    78Suburban 1/2 ton status

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    My engine is having a dieseling problem, and I'm not wanting to bend any more pushrods than I have to............ I have a th400, will it hurt the tranny if I shut it off in drive instead of park, then move the gear up into park? I know I need to fix the dieseling problem, but Im just wondering if I'm gonna mess up the tranny doing this as a temporary solution?

    thanks,
    James
     
  2. onetonbb74

    onetonbb74 1/2 ton status

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    no, wont mess anything up.
     
  3. 1979jimmy350

    1979jimmy350 1/2 ton status

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    it should not break any thing to shut it off in drive, you should be fine. You might want to try some seafoam to try and clean some of the carbon deposits to try and prevent the problem in the first place
     
  4. bigbadchev84

    bigbadchev84 1/2 ton status

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    lower your idle or check for a vacuum leak
     
  5. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    Good idea.

    Have you stuck a vacuum gauge on it, and if so, what does it read at idle?
     
    Last edited: May 14, 2006
  6. fatbob

    fatbob 1/2 ton status

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    I say adjust your timing to stop the dieseling.:laugh:

    Hey, its a cheap and easy fix.:wink1:
     
  7. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    You have to lower the idle speed if the timing is right for your motor/cam etc . Then recheck the timing at the new idle speed . Two way street . Adjust both .

    My truck idles at 500 rpm in gear , no stalls :thumb:
     
  8. 78Suburban

    78Suburban 1/2 ton status

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    alright guys, I'm gonna clean off the carbon deposits on my plugs, or maybe even buy some new plugs. I'm gonna set my idle speed alot lower. I may run some seafoam through the tank. any other ideas ? I know dieseling isn't the most healthy thing for a motor.
     
  9. colbystephens

    colbystephens 1 ton status GMOTM Winner

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    can someone define dieseling for me?
     
  10. pvfjr

    pvfjr 1/2 ton status

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    It's when you shut off your motor (meaning the ignition has been cut), and it keeps running. Since it's running without spark, it's referred to as dieseling. Usually it consists of a lot of knocking and various other bad noises, and should be stopped as soon as possible.
     
  11. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    The engine continuing to run in the absence of spark ("run-on"). Kachug kachug kachug, sometimes folowed by a nasty final backfire through the carb.

    Common to very lean-mixture carbureted vehicles of the mid 70 to mid-80s.

    EFI eliminated the problem because when power to the FI system is cut, the fuel stops, whereas in carbed engines, the fuel was available even after the ignition was switched off.
     
  12. colbystephens

    colbystephens 1 ton status GMOTM Winner

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    so what does that have to do with shutting it off while in gear?
     
  13. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    It lowers the idle speed and gives the engine a load to work against, and that prevents that few seconds of run-on.
     

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