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Cold rainy days

Discussion in 'The Garage' started by 84mudmachine, Mar 24, 2005.

  1. 84mudmachine

    84mudmachine 1/2 ton status

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    The past few days it has been in the 35-40 degree range with rain, and it seems that the blazer doesn't want to idle worth a darn until it reaches full temp around 190. A few months ago and put on a oem air intake with a modified heat riser for headers, and it has been doing very well until this week. Ingnition is new, carb is new bebuilt q-jet, which was tuned by my local shop, so I am having a problem figuring out this problem. Their was one day this week that was a bit warmer and dry, and it had no problem, but it came back today with the rain last night and cooler weather. Any idea, or is this just the way carb trucks are?
     
  2. diesel4me

    diesel4me 1 ton status Premium Member

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    icy carbs...

    Sounds like your carb is icing up on those cold damp days--it can frost up as high as 50 degrees,the air rushing into the carb venturi's can cause any moisture to turn to ice and clog the throttle butterflies,shutting off all the air to the motor,and it stalls-

    -I bet it runs ok if you hold it at a fast idle--my edelbrock performer is notorious for this,I had to use a spacer/adapter to make it fit the Q-jet OEM manifold,and that blocks all the heat from the intake from getting to the carb--it takes 20-30 minites before it will idle normally on cold damp days-(and we have lots of them here:mad: )-

    -I tried putting the original gm air cleaner with the hot air pipe to the exhaust manifold,and made sure the "door" in the snorkel works as intended factory--it helped some,but it still aggravates me--didnt cure it completely..

    I think it would not be so bad if the "heat riser" thing was hooked up and working--it goes in the passenger side exhaust manifold,(where the studs are for the Y-pipe)and has a butterfly that blocks all the exhaust from that side of the motor from going out the Y-pipe,and forces it to go thru a passage under the carb,warming it up considerably-

    -but mine is disconnected,I havent had time to find out which ported vacuum switch runs it yet...If you have headers,its no longer there,so you have to more or less live with the constant stalling out at stop signs,or "power brake" it slightly to keep it running,until it fully warms up----a PITA!!--:mad:

    -I have discovered adding a few bottles of isopropanol dry gas helped a great deal,almost eliminates the problem completely--but I'm not sure if a steady diet of alcohol is good for the motor..I only use it when I know its going to be cold and damp,not all the time--once its above 55 degrees,you'd never know it had this problem...:crazy:
     
  3. 84mudmachine

    84mudmachine 1/2 ton status

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    wow, thanks for the indepth write up. I figured I would just have to live with it. I have been power breaking, that works fine, I just can't wait till it warms up. Thanks again........:)
     

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