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.

Dieseling ?

Discussion in 'The Garage' started by lugnut, Mar 3, 2004.

  1. lugnut

    lugnut 1/2 ton status

    Joined:
    Aug 3, 2001
    Posts:
    268
    Likes Received:
    0
    Location:
    North Carolina
    I got a good deal on an 85 C30 with a good running 454. The problem is it doesnt want to stop running it runs back for a few seconds after you shut it off. The smog pumps and related hardware have been removed by the PO and I was thinking the EGR valve might be my problem. I have tryed adjsting the timing and carb but it has not helped. Anyone got any sugestions ( I know I'll have to put the smog goodies back on but dont want to at this time ) Thanks
     
  2. jakeslim

    jakeslim 1/2 ton status

    Joined:
    Sep 18, 2002
    Posts:
    2,686
    Likes Received:
    0
    Location:
    Napa, CA
    new carb fixed that for me. It's pretty embarassing when you stop somewhere and the stupid thing sputters on and on and then gives a big burp..geez.
     
  3. POWERMAD

    POWERMAD 1/2 ton status

    Joined:
    Mar 4, 2001
    Posts:
    3,466
    Likes Received:
    0
    Location:
    Oregon
    Timing to far advanced and the idle set to high are the main culprits of run on(deiseling)
    Did the PO use the rig for tow duty?
    How many miles are on the clock?
    Carbon build up on the tops of the pistons can cause deiseling. If the rig spent most of the time at lower RPMs it may have an excessive build up of carbon.
    I have seen them so bad that it cracked a piston.
    What can happen is the carbon gets hot and stays hot enough
    that it will continue to ignite fuel for a few seconds after the engine is shut off.
     
  4. big jimmy 91

    big jimmy 91 1/2 ton status

    Joined:
    Feb 21, 2004
    Posts:
    639
    Likes Received:
    0
    Location:
    Northwestern Ontario Canada
    An easy fix for dieseling caused by carbon buildup is:
    run engine till hot without air cleaner on
    take a 2Lpop bottle full of water and slowly pour it down the carb while keeping it reved up to around 2-3000 rpm
    do not let it stall
    do not pour the water too fast
    do not over rev the motor(that is really bad)
    This method works very well , I have done it to 3 or 4 of my own vehicles over the last 15 years
    You may have to remove and clean spark plugs when done(I usually did mine before a tune up that I was replacing plugs anyway)

    THE CANADIAN REDNECK METHOD LOL /forums/images/graemlins/yikes.gif
     
  5. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

    Joined:
    Jan 27, 2003
    Posts:
    3,254
    Likes Received:
    0
    Location:
    Castro Valley, CA
    choke not opening all the way.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,975
    Likes Received:
    189
    Location:
    Roy WA
    I wouldn't worry about the EGR.

    Only problem I ever had was from the idle AC kicker on the carb. Thing was messed up, kicked idle up when I turned the key off, which kept it running, or tried to anyway.
     
  7. ZooMad75

    ZooMad75 1/2 ton status Premium Member GMOTM Winner

    Joined:
    Apr 5, 2003
    Posts:
    998
    Likes Received:
    592
    Location:
    Pueblo, CO
    excessive Idle speed adjustment is a real common cause. When the engine is shut off the throttle blades should be almost closed or actually closed if you have a a/c compensator solonoid.

    If you don't have the a/c solonoid you may want to go back and reset the idle speed and mixture to bring it back down. If you do have the a/c solonoid, when running set your Idle speed with the solonoid (like a 3/8" wrench on the plunger). Adjust your actual idle speed screw to a lower setting so that when you shut the engine off and de-energize the solonoid the throttle falls back to the idle speed adjustment screw on the carb and the throttle is closed off.

    That solonoid was used as an anti-desieling device on GM cars/trucks that did not have a/c too. Those are wired on a keyed 12v source so they engage as soon as the engine is fired up, not just for when the a/c engauged. My 69 Nova had one on the 2bbl it came with.
     
  8. lugnut

    lugnut 1/2 ton status

    Joined:
    Aug 3, 2001
    Posts:
    268
    Likes Received:
    0
    Location:
    North Carolina
    Yea this thing has been a tow rig all its life both POs used it to pull race cars. It has about 90,000 miles on it. It does not have the AC sol. on it and I forgot to mention that the Q jet was replaced with a Carter. From what everyone is saying I geus I need to get the timing light back out and start tuning. Thanks to all
     
  9. lukebaby1

    lukebaby1 1/2 ton status

    Joined:
    Dec 16, 2003
    Posts:
    231
    Likes Received:
    0
    Location:
    Richmond, Virginia
    You can always just leave it in drive with your foot on the brake and cut the ignition, then shift to park.
     
  10. ZooMad75

    ZooMad75 1/2 ton status Premium Member GMOTM Winner

    Joined:
    Apr 5, 2003
    Posts:
    998
    Likes Received:
    592
    Location:
    Pueblo, CO
    [ QUOTE ]
    You can always just leave it in drive with your foot on the brake and cut the ignition, then shift to park.

    [/ QUOTE ]

    That will always stop that crap! Passengers riding with you tend to look at you funny when you do it though.
     

Share This Page