Spark Manual

Posted on Feb 5, 2014

The controller box is the MegaSquirt EFI Hardware. The MegaSpark was originally designed & tested on v2. 2, but may work on other versions. The software was designed to yield a fully functioning advance controller with no modifications to the MegaSquirt Hardware (beyond the normal MegaSquirt tach input experimenting). Some options may require modi

Spark Manual
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fications or an additional daughter board. Please refer to the above link and for questions on purchasing and building the MegaSquirt hardware. The MegaSpark is designed to operate with *one and only one* input trigger per spark. This requirement can be satisfied in a variety of different ways. The input source can come from the distributor (required to be locked), crank, cam, flywheel. As with MegaSquirt, some experimenting maybe required depending on the sensor. A clean input signal is an absolute must with MegaSpark! The input trigger must occur at least 5 crank degrees before the total desired advance (for 8K RPM, increase to 8 crank degrees before for 12K RPM). Also, it must occur after the prior spark - this places a maximum on the degrees BTDC of the input trigger: For Odd-Fire: The "Static Timing" must be less than the shorter spark interval. For example, on a V-6 with 90 degree & 150 degree spark intervals, the input trigger must be closer than 90 crank degrees BTDC. Also, each trigger must occur at the same degrees BTDC for each spark, so the spacing of the triggers must match the odd interval spacing of the sparks. This means that engines that have an odd number of sparks per crank revolution, such as a 4-stroke 6 cylinder (3 sparks per rev), can not trigger off the crank. When mounting a sensor, it is suggested to position it for an input trigger ~45 crank degrees BTDC. This will allow up to 40 degrees total...

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