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Thread: Hard start and won't idle.

  1. #11
    Join Date
    Dec 2009


    Originally Posted by Danny Cabral
    The Sniper EFI doesn't have the same TPS Autoset function as the Terminator, HP & Dominator ECUs. The Sniper EFI calibrates the TPS sensor
    at every key-on event. If replacing the TPS, the TPS sensor is located at the end of the primary throttle shaft, opposite end of the throttle lever.
    It's slotted, so install it in the same position. Holley 543-111 TPS or Standard Motor Products TH191 TPS. (Replacement Sensors For Holley EFI - Auto Parts Store)

    Sniper EFI Idle Setting/Throttle Blade Setting (Holley Sniper EFI Quick Start Manual):
    Once the engine is up to operating temperature, the idle speed can be set to what was configured in the Wizard.
    To do this, open up the Initial Startup gauge screen that was used in section 17.0. With the vehicle in neutral,
    adjust the idle screw until the IAC Position reads between 2 & 10%. While adjusting the idle speed screw, if the
    TPS Position begins to read higher than 0%, cycling the ignition switch will recalibrate the TPS back to zero.
    This explains the idle speed screw/IAC Position % relationship that must be properly set for idle control.
    NOTE: Do not attempt to set the Target Idle Speed and IAC Position until the engine is above 160°F! (Holley Sniper EFI Quick Start Manual - "Idle Setting/Throttle Plate Setting", Page 12)! (Sniper EFI High Idle Thread)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  2. #12


    The Bronco started right up this morning with a cold engine, so I decided to let it get up to temp and adjusted the IAC. Wow, that idle screw is very touchy. I was turning it like I would on a carb, but it sent the IAC reading all over the place. So I learned to make very small adjustments and recycled the key when the TPS moved off zero. I now have IAC at 5-6 when idling.

    While looking around on here last night I also found the throttle lever extension thread so I made one of those. It makes a huge difference in the response. My son was gone in the Bronco all day, so I haven't pulled another datalog since I have set IAC correctly again. I will do that and see what the overlay looks like. Thanks all, Chuck

  3. #13
    Join Date
    Oct 2017
    Los Angeles


    Nice to see you got it working again, and your son hasn't called for a tow!

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