engine seems to miss after 150 shot

Discussion in 'Competition Camaros' started by camaro454, May 8, 2012.

  1. 1980RS

    1980RS Veteran Member

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    Carb too fat?, I had that one time at the track got the car home leaned it out and ran great after that.
     
  2. Pc3

    Pc3 Veteran Member

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    I take it wires are on correct and not arching espeacilly at the cap. lights out run car look for spark jump
     
  3. camaro454

    camaro454 Veteran Member

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    Yes wires are correct. Haven't done the dark test but they are new wires. everything was fine I hit nitrous a couple times with no problems no pops no backfires miss or nothing had timing turned back 6 deg had 4 heat range cooler plugs and rpm window switch with wot throttle switch window switch turn on 3000rpm and shut off at 5800rpm never hit the rev limiter or nothing everything felt great then this miss on the way back to the house...:mad:
     
  4. camaro454

    camaro454 Veteran Member

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    How would it all of a sudden get to fat?
     
  5. 1980RS

    1980RS Veteran Member

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    It can go fat just from bad air, that is if the barometer goes low, or too much moisture in the air. 2 years ago I ran my car at the track for a baseline and the car ran mid 12. Fast forward to this last weekend and what I had thought to be better air turns out to be bad air. I had jetted up the carb from the time 2 years ago but ended up going 4 jets leaner with my 750 holley after I had put my 850 demon on it and noticed that the car slowed way down.

    The demon was crisp on the pri. side but way fat on the sec. side (93 jets) so at that point I knew I was too fat. The next run the car was running great and on decel the popping / burbling was gone and the car was close to the 12 flat range N/A.

    Like I said earlier my 406 fooled me on that one day when I thought I had some sort of problem and it was just too high of a float level and too rich. Went back to the track that time and the car was a solid 2 thenths and 2 mph faster. Would be easier with a wide band but looking at where the black ring is on the spark plug works just as good for me.
     
  6. Blown Camaro

    Blown Camaro American by birth, drag racer by choice

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    Surge=lean and since it didn't have a surge before, then you have developed a vacuum leak somewhere.
     
  7. MassD

    MassD Veteran Member

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    Get a can of carb cleaner and spray it around the base of the carb the intake manifold runners etc while the car is running. When you spray the area with the vaccum leak the engine will stumble or die and thats how you know where the leak is.
     

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