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Thread: Sniper & A/C

  1. #1
    Join Date
    Jan 2018
    Location
    Holmen, WI
    Posts
    12

    Default Sniper & A/C

    I have not purchased SNIPER EFI yet, however, I'm well into reading the entire installation manual. I'm wondering how SNIPER works with A/C. Can it increase idle speed when A/C turns on? I believe I read of its ability to kill the A/C at WOT. I'm more interested in how it behaves with A/C in normal driving conditions. Would like to hear from those running SNIPER & A/C. Thanks! Shoebox

  2. #2
    Join Date
    Nov 2014
    Location
    Ont. Canada
    Posts
    1,743

    Default

    Download the Sniper EFI software and then you can see what it does.

  3. #3
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    27,477

    Default

    1) See the A/C IAC Kick function. Like the Terminator, HP & Dominator EFI, it's only a momentary increase in IAC.
    Are you looking for a momentary increase in IAC or a high idle function? The A/C "IAC Kick" function only produces a momentary increase in IAC, so the engine RPM doesn't dip down when the A/C is turned on (or in your case, electric fans). It works fine, but it does not increase & hold the idle RPM like a high idle function. Actually, the IAC Kick function is usually not necessary. It's typically a tuning issue with the Base Fuel Table. If you need a high idle function, it can be programmed in the Sniper EFI software Advanced ICF: (1D Table, "Target Idle Speed Offset" Table Type, Switched Enable - Input #1/#2, Enabled, or Advanced Enable - A/C Kick Activation, Above) to use as a high idle function. https://forums.holley.com/showthread...8837#post88837 (Related Forum Thread)

    For more information about RPM dip/instability when electric fan(s) or A/C turns on:
    https://forums.holley.com/showthread...115#post242115 (Fast Idle Function For Electric Fans - Sniper EFI)
    https://forums.holley.com/showthread...839#post211839 (IAC Kick For Electric Fans - Terminator/HP & Dominator EFI)

    2) The Sniper EFI electric fan ground wires (pin C, light blue - Fan #1 & pin D, light green - Fan #2) trigger the relay coil − (terminal #85). Yes, terminal #85/Ground is the industry standard for good quality relays, with or without a diode. Sniper EFI instruction manual: LINK - page 17 & 50.
    Electric Fan #1/#2 relay terminals (ECU ground signal scenario):
    #85 - Ground signal from Sniper ECU Output.
    #86 - Fused +12V power to relay coil.
    #30 - Fused +12V power to relay contact.
    #87 - +12V power to electric fan.
    #87A - Not used in this application.
    Terminals #30 & #87 can be reversed.
    http://www.autoshop101.com/forms/hweb2.pdf (Understanding Relays)
    Any amperage, general purpose, four terminal relay will do. However, if you want the best ECU protection, a suppression type or diode protected relay can be used. Scroll down to section 5 of this LINK for more relay information.

    If your A/C compressor is ground activated, this works perfectly with the Sniper Input #1:
    See page 8, "10-Pin Connector": http://documents.holley.com/199r11193.pdf (Holley Sniper EFI Quick Start Manual)
    Converting A/C signal wire from +12V A/C compressor clutch wire to Sniper's negative A/C IAC Kick signal wire (Input #1) with a relay: https://forums.holley.com/showthread...699#post206699 (Sniper EFI A/C Compressor Signal Wiring Info)
    Any amperage, general purpose, four terminal relay will do. However, if you want the best ECU protection, a suppression type or diode protected relay can be used. Scroll down to section 5 of this LINK for more relay information.

    3) If you're using the Holley EFI A/C Shutdown feature, it requires a relay for operation. It usually triggers a preexisting A/C WOT relay.
    http://forums.holley.com/showthread....9130#post49130 (Addition Information - Read Post #2 & #10)
    Any amperage, general purpose, four terminal relay will do. However, if you want the best ECU protection, a suppression type or diode protected relay can be used. Scroll down to section 5 of this LINK for more relay information.

    4) FYI: The A/C IAC Kick input must be used for the "Enable Fan #1 When A/C On" to function.
    Page 19, "Enable Fan #1 When A/C On": http://documents.holley.com/techlibrary_199r11259.pdf (Holley Sniper EFI Help Manual - EFI Software, Tuning & Datalogging)
    Then assign the A/C IAC Kick wire in the Sniper EFI software to Input #1.
    See page 8, "10-Pin Connector": http://documents.holley.com/199r11193.pdf (Holley Sniper EFI Quick Start Manual)

    5) Holley Terminator, HP & Dominator EFI users:
    The Holley V5 EFI software/ECU firmware finally added an A/C activated option for the electric fans. Check mark A/C "IAC Kick"
    in the Holley EFI software (Basic I/O - System Parameters), select a +12V or Ground Input Type in Inputs/Outputs (still in the
    System ICF), and Pin Map it to an available "H" (+12V) or "G" (Ground) Input Type pin. See below for more information.
    http://documents.holley.com/techlibr...teoverview.pdf (Holley EFI V5 EFI Software Update Overview - Pages 7 & 8)
    https://forums.holley.com/showthread...205#post237205 (Alternative Electric Fan Control in Inputs/Outputs ICF)
    Quote Originally Posted by Holley EFI V5 EFI Software Update Overview
    Fans, Pumps, A/C
    A checkbox is now available for Fan #1 & Fan #2. This ONLY appears if the A/C "IAC Kick" input is selected
    & used. When the A/C IAC Kick input (an input triggered when Air Conditioning is active), the user has the
    option to have one or both of the fans automatically come on, independent of engine coolant temperature.
    Click image for larger version. 

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