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  • #1

    New motor issues

    ok so i spent a lot of money and time getting my new motor into the car.. everything is hooked up the right way but SOMETIMES when im driving itll seem to almost want to die out on me.. like the motor revs up to go but then it almost just stops then goes again. it doesnt stop for long only like a second or 2 then its fine... its a GM creat motor and its carburated.. the only thing i could think of thats causing this is the fact i dont have an exhaust system yet. JUST HEADERS.. (no back pressure)

    one other problem im having is when i really lean on the gas the car moves ok but the ammount of exhaust i trail is a big concern... maybe i killed the valves?

    lets just say it is the valves where online can i go to find out how to replace them cause idk how to do it and i dont have the money for someone else to.
    1987 Formula Firebird
    GM crate 350 5.7L carburated
    MSD, Edlebrock intake and carb, Dynomax headers
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  • #2
    Did you have the carb tuned.... sounds like its running rich? What color is the smoke from the exhaust? Has the ignition advance curve been set up for the engine?

    An engine doesn't need "back pressure" on the exhaust. But an open exhaust will lean out a carbed engine, and that has to be accounted for in the turn. Sounds like it needs some tweeking.

    Did you modify the stock fuel system to provide the required pressure for the carb?

    PS: "Crate" engine
    Fred

    381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motor

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    • #3
      Yeah the fuel system has been changed for the motor.
      the smoke is real white looking. maybe a hint of blue ish color.
      "Has the ignition advance curve been set up for the engine?"
      im sure it has the shop that put it all together specializes in motors and hot rod kinda stuff. there not stupid they know there stuff . but the running rich sounds like a good guess. im new to the carb- how do i make it more lean. (2barrel)
      1987 Formula Firebird
      GM crate 350 5.7L carburated
      MSD, Edlebrock intake and carb, Dynomax headers

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      • #4
        I'm not suggesting anyone is stupid.... just trying to get enough info to help you. Sorry if that's the way you feel.

        If the smoke is white, there's a good chance its coolant.
        Fred

        381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motor

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        • #5
          why are you running a 2 barrel on a 350 crate motor? it also sounds like it's running rich to me. maybe the timing is off some also.
          87 GTA: it's winter time, all tore apart

          ConElite: "Im 22, have had my TA since I was 21."

          "I wont lie, I have a heavy foot, but at the same time I know when its the safest to ring out a gear or 2."

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