The module is essentially an amplifier with a built in analog to digital convertor Easy tests for hei system Test for power at the pink bat terminal You should have battery voltage w/ the key in the start and run positions Connect the ground side of your test lamp to the battery positive. Having a no spark issue on your gm engine
Central to the hei system is the ignition control module, a small but crucial component responsible for timing and triggering the ignition coil to fire the spark plugs. It's more likely that the coil would go out before the module There are some tests you can do but the loaded tests at the auto store testing machines are best for this Are you certain that the distributor is installed correctly with tdc #1 firing position with rotor pointing to #1 plug post. If there is power, disconnect the electrical connector and remove the cap Check the rotor and the cap for excessive wear
Remove the top plastic cap on the distributor cap Use an ohmmeter and check the coil. In a gm hei system, the module replaced the contacts of the breaker points and the pickup coil was substituted for the rubbing block and distributor cam The ignition coil fires when the module shuts off voltage to the coil primary. To test reluctor pickup with a digital multimeter, set to low ohms, measure across the two leads that are connected to the gm hei module but disconnect them first.
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