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MS1-Extra

MegaSquirt v2.2 Crane XR700 Ignition
using LED 17 (D14) output

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.

Below is the wiring for the Crane XR700 optical trigger driving the MegaSquirt ECU and using the Crane box to drive the coil.

In this configuration, the Crane optical trigger drives the MS v2.2 and the IDL out drives the Crane amplifier that in turn drives the coil. The Crane XR700 does not have any intelligence, so it is best to use the MSnS-Extra dwell control.

  1. Remove D5, R10
  2. Remove jumper between XG1 and XG2
  3. Replace D8 with a 1.3 (or 1.3 to 2kohm) resistor 1/2 Watt or greater.
  4. Fit a wire between between XG1 and right of D5 (the side that goes to pin 24/coil)
  5. Fit wire between bottom of R10 (where R10 and D8 are tied together) and right side of D9 (+12V)
  6. Fit a wire from the top lead of D17 (going to Q9) and jumper X11

You can test your input connection by monitoring IRQ-1 at R11. First set up MS to monitor IRQ with the center front panel LED. Disconnect power to the coil. Put on the hand brake and the transmission in neutral. Now turn the engine such that the crank pulley passes from 20º BTDC to TDC. The IRQ LED should go from On to OFF at ~10º BTDC for most cars with distributor (but it may be from 5º to 15º, usually this is called the static timing)

You do not need to use the Crane coil driver. Instead of the output circuit of Q9 and D17 inside MegaSquirt 2.2 add a coil driver.