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MS1-Extra

MegaSquirt This Cylinder Mode with
Time based Cranking Set Up

Only for use with the MS1 Extra code (MS1 - 68H908 based microprocessors)

By Philip Ringwood (daxtojeiro), James Murrey (jsmcortina) and Ken Calver (muythaibxr)

Please Note:

All of these instructions / diagrams are to be used at your own risk, like most things there is more than one way to do the same thing, what we have tried to do is to offer a method that we have tested or that others have tested for us. No warranty expressed or implied.

Use at your own risk.

 

First set up MegaTune to help you time the distributor. Set the center LED on the MegaSquirt front panel to show the state of the IRQ-1 inside MegaSquirt.

In these instructions, the ignition sensor is located on a movable plate to position the sensor for This Cylinder mode while maintaining the correct alignment for the rotor.  

Caution:
For your safety, you must disconnect power from the coil to prevent a spark.

With the distributor ignition wired to MegaSquirt, coil disconnected and ignition on:

  1. Set the crank at 20º BTDC at cylinder #1
  2. Rotate the distributor so the rotor arm points towards the correct contact (#1 cylinder) in the distributor cap. Fasten the distributor. Alternately locate the distributor in its normal pre-MegaSquirt location to correctly align the rotor with the high voltage towers.
  3. Fix/fasten the distributor.
  4. Set the crank at 60º BTDC for cylinder #1
  5. Rotate the advance plate with the sensor in the direction of shaft rotation until the LED just turns OFF.
  6. Rotate the advance plate back in the opposite direction until the LED just turns ON again.
  7. Fix/fasten the advance plate. This fixes the Trigger Angle at about 60º BTDC
  8. Test your handywork. Turn the crank from near 90º BTDC in the direction of rotation. The center LED should go ON at approximately 60º BTDC.
  9. Enter 60º for Trigger Angle. This need only be an estimate. You will adjust this dynamically with a timing light later.
  10. Enter 10º (or the engine static angle) in Cranking advance Angle
  11. Enter 10 for Fixed angle (This forces the running advance to be 10º BTDC)
  12. Turn off ignition and connect ignition coil
  13. Start the engine
  14. Adjust the Trigger angle entry until the timing light is at 10 degrees (This calibrates the estimated Trigger angle)
  15. Set "Fixed angle" to -10 (to use the Spark table)
  16. This completes the setup for This Cylinder distributor ignition

Example settings for This Cylinder mode with Time Based Cranking Timing. Trigger Angle greater than 50º determines This Cylinder mode. The Spark Output Inverted selection depends on your install and is not dependent on the choice of This/Next cylinder mode.


 
 

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