MEFI Fuel Injection
Ignition Control Module - Running
Ignition Control Mode (running mode) When the RPM exceeds 400, the ECM considers the engine running and applies 5 volts on the by-pass at terminal “B”. This energizes the “relay” and causes the contact to open, this un-grounds the IC line and connects it to the base of the transistor. This switches ignition control to the ECM. Now the ECM is sending the trigger signal to the base of the transistor over the IC circuit and controlling the firing of the ignition coil primary circuit. The Ref Lo signal at terminal “G” is a ground. This is the low current ground or return back to the ECM for the electronics in the IC module. The high current that comes from the ignition coil gets grounded through the module mounting bolts. It is important that there is a good ground through these bolts. A poor ground will result in a poor running engine. See page 4-6 in the “EF” manual or pages 38 and 39 of 742218 manual for results of incorrect operation such as an open IC line or grounded IC line, etc.
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