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Thread: 4 Cylinder Clarification on Injector Strategy

  1. #1

    Default 4 Cylinder Clarification on Injector Strategy

    My setup: Holley HP on 4 cylinder motorcycle 12-1 crank wheel and no cam sync (35 year old engine design). Firing order is 1-2-4-3. Reading “Fuel Injector Information - Strategy” in the Help guide. Can I assume the descriptions given are specific to 8 cylinder engines? And for a 4 cylinder engine I would double the crankshaft degrees listed? For a 4 cylinder:
    Bank to Bank - Would fire half the injectors and then the other half every 360° (1 & 4 inject at 0° and 540°, 2 & 3 inject at 360° & 720°.)
    Untimed Sequential - Would fire each injector every 180° (1 injects at 0°, 2 injects at 180°, 4 at 540°, and 3 at 720° **OR** 4 at 0°, 3 at 180, 1 at 540° and 2 at 720° — just depends on where the cam is the first time the crankshaft comes around?)
    Paired - Would fire a pair of cylinders every 180° (1 & 4 inject at 0° & 360° and 2 & 3 inject at 180° & 540°)
    To run paired, I have to wire the injectors in pairs? Injector 1 output to both cylinders 1 & 4 and injector 2 output to cylinders 2 & 3? (And leave injector outputs 3 & 4 unconnected.)
    Thanks! All the other questions I’ve had, have been covered in the forum, just a little confused on this one (mostly caused by my experience with other ECUs we’ve used on the bike prior).

  2. #2


    You need to wire 4 injectors to 4 outputs.
    Full body, full frame, laddered RWD Honda Civic.

  3. #3
    Join Date
    Dec 2009


    In the Holley EFI software, see the "View Injectors" screen in the Pin Map for ECU connector & pin-out. This indicates the injector drivers (A-H), and which J1 Connector pin they're wired to.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, 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.

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