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Thread: IAC Parked Position/hard starting.

  1. #1

    Default IAC Parked Position/hard starting.

    On my recent Sniper EFI install, the engine struggles to start when warm due to over fueling. And wouldn't restart without opening the throttle blades.
    I called the tech line, and they had me rerun the wizard and select race cam:
    SBC, 244° @ .050 109° LSA. (I think Street strip setting was probably fine.)

    Per their recommendations, changed Cranking Fuel 26 lb/hr, After Start Enrichment 130%, and the Fuel Prime Percentage down to 100%. It does restart and go to its Target Idle and runs really well.
    However, warm restart seems inconsistent after cooling down completely and warming again.

    Should I increase the IAC Parked Position to a higher percentage when warm? Since I believe it needs more air on startup.
    Currently the graph shows about 65% at operating temperature, and should still be the default setting.
    Is a higher IAC Parked Position %, indicate a greater opening of IAC or vice versa? Thanks, C68.

  2. #2


    My engine (390 ci 245° @ .050, 110° LSA) always needed some throttle opening when warm to start with every carb I had on it. With the Sniper EFI, I just park my IAC at 100% at all temperatures with a fast ramp down. Definitely starts better when hot. I also had to reduce my Cranking Fuel much more than that. Haven't quite nailed hot start yet, but it's a lot better than the base setup.

  3. #3
    Join Date
    Dec 2009


    Quote Originally Posted by Cheverra68 View Post
    Does a higher IAC Parked Position %, indicate a greater opening of IAC or vice versa?
    Yes, the higher the IAC Parked Position %, the greater the airflow. (Good Starting Advice Thread - Especially posts #2, #4 & #6.) (Initial Checks & Adjustments - Read Step #3) (General IAC Information - Read "IAC NOTES")
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

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