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MAP issue?

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  • MAP issue?

    I've installed a PF4 on a basically stock 350 Chevy. When it starts, it idles fine at around 800 rpm, but will not rev up when I touch the gas pedal. I unplugged the MAP, restarted the car and it revs like crazy when you touch the gas but it will not idle. Any help would be really great. Thanks

  • #2
    What kit part number? What cal did you load? What cam specs? How much vacuum at idle? What is AFR, AFR SP and Short FT at idle? So you zing throttle to almost wide open and the engine stays idling at 800 rpm? Or if you increase the throttle slightly and hold it the engine stays at 800 rpm or does it bog or does it cough, etc etc etc? What lead you to unplug the MAP sensor? Does TPS and MAP read on the tablet? Did TPS and MAP change values when you applied throttle with the engine running? When you try to rev it up, what is AFR, AFR SP and Short FT with the MAP sensor plugged in? What is AFR and Short FT when you rev it up with the MAP sensor unplugged?


    • #3
      Sorry I'm just getting back to you now Nate, but I've been working on the car every day. Today an Edelbrock Tech figured out that the MAP sensor was bad. With the engine off is was showing -18.4 inches on the vacuum display. When the engine was idling, it showed -25.5 inches. It's a stock 350 chev with a very mild cam of 212 degrees on the intake and 222 degrees on the exhaust.