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Engibe trouble

Discussion in 'The Garage' started by adamforsythe, Feb 23, 2006.

  1. adamforsythe

    adamforsythe 1/2 ton status

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    What would cause a heathy 350 to fall on it's a$$ when you really hit the gas? I leaned the piss out of the engine to try and fix it but it only made it worse. I am running a Edelbrock 600CFM carb with a accel super coil. It does have a very mild cam it it around 213 at 050.
    Thanks
    Adam
     
  2. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    I had a similar prob with my EB, a flat spot under light acceleration. If I really punched it, it was fine. This was the solution to my problem (from the manual):



    The Step-Up function, which moves the Metering Rod to the Power Mode, is controlled by the Step-Up Spring. The base calibration has a spring which “stages” rich at 5” Hg. If your vehicle has a mid-throttle driveability problem that is encountered as the throttle is gradually opened, but then goes away upon further opening, it may be possible to eliminate the lean spot by using a stronger Step-Up Spring. The available Step-Up Springs are listed in the following chart along with their respective “staging” point. It is best to select a new spring on the basis of vacuum readings, but in the absence of a gauge, try the strongest spring (highest vacuum rating) to see if the problem goes away. If the drive problem is cured by the strong spring, try the next weakest spring as well. If the strong one does not help, then the calibration problem is related to the A/F metering stage of either the Cruise or Power Modes.




     
  3. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    Short summary: I needed a stronger step-up spring (mighty cheap) to lift the rod sooner (less throttle, higher vacuum) and that got rid of my lean flat spot.
     
  4. adamforsythe

    adamforsythe 1/2 ton status

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    I think my problem is a little different. Once my engine falls on it's face I have to let off for it to go away then I have to slowly mat the gas. It does not do it all the time.
    Thanks
    Adam
     

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