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Thread: 60-2 Trigger Without Cam Sync

  1. #1

    Default 60-2 Trigger Without Cam Sync

    When not using a cam sync, do the injectors fire twice? How does the ECU know when the the cylinder is on the intake stroke?

  2. #2
    Join Date
    Feb 2015
    Melbourne, Florida


    With that setup you will find 3 settings in the drop down for injector strategy; Bank-To-Bank, Paired & Untimed Sequential. Bank-To-Bank fires one bank every 180 crank degrees to try & balance out the intake mixture. Paired works like waste-spark, but it doesn't know what cylinder it is on, so it starts at random. Untimed Sequential also starts on a random injector, but then follows the firing order, and that is the one I recommend you try for port mounted injectors. However, your engine might like another setting better, so once you have a base table, try changing between them to see if one runs better. If you have a chance to later, I would add a cam sync to your system. Danny will give a good link in the morning I'm sure.

  3. #3
    Join Date
    Dec 2009


    Quote Originally Posted by jeostang View Post
    When not using a cam sync, do the injectors fire twice?
    Not exactly, you still choose the injection strategy in the EFI software.
    The new Holley EFI systems are capable of four types of injection strategies:
    • Bank-to-Bank ― Fires half the injectors and then the other half every 180 crankshaft degrees (injectors fire once per revolution).
    • Untimed Sequential ― Fires each injector every 90 degrees. But since there is no cam sync signal, it is random which cylinder is first triggered.
    • Paired ― Similar to Bank to Bank, except only two injectors are fired at a time (fires a pair of injectors every 90 crankshaft degrees).
    • Sequential ― Fires the injectors in sequence of engine's firing order (requires cam sync sensor).

    How does the ECU know when the the cylinder is on the intake stroke?
    A 60-2 crank trigger gets its signal from the two missing teeth on the 60-2 trigger wheel (#1 cylinder), and the 10th tooth after the missing teeth (Ignition Reference Angle - read next paragraph). The two missing teeth send the TDC signal every time #1 cylinder is up (near TDC of compression stroke and near TDC of exhaust stroke). It doesn't know when the #1 cylinder is ONLY on the compression stroke, hence the need for a cam sync sensor for sequential injection and/or CNP ignition. If you don't need or want sequential injection/CNP ignition, then you just need an oil pump drive plug.

    The ECU needs an Ignition Reference Angle, so it can control the timing.
    The TDC Tooth Number (amount of teeth after missing teeth) is the Ignition Reference Angle.
    On a 60-2 trigger wheel, each tooth equates to 6 degrees. 60 x 6° = 360°.
    The Ignition Reference Angle needs to be at least 10° higher than the maximum amount of timing used.

    12 teeth is 72° of Ignition Reference Angle, which allows you up to 62° of timing advance (in the Base Timing Table).
    11 teeth is 66° of Ignition Reference Angle, which allows you up to 56° of timing advance (in the Base Timing Table).
    10 teeth is 60° of Ignition Reference Angle, which allows you up to 50° of timing advance (in the Base Timing Table).
    9 teeth is 54° of Ignition Reference Angle, which allows you up to 44° of timing advance (in the Base Timing Table).

    It gets confusing because for a 60-2 crank trigger, the EFI software uses the term "TDC Tooth Number" to describe the Ignition
    Reference Angle. Which is fine, since the amount of teeth (after the missing teeth) is more of a definitive method to identify it. (Crank Reference Angle Importance)
    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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