Distributor Pick-Up Coil Short & Resistance Checks

1. Disconnect pick-up coil leads from HEI-EST module terminals "N" and "P". Set ohmmeter to middle scale, and connect one lead to either pick-up coil lead and other lead to distributor housing. See Fig 1. Flex pick-up coil leads by hand to check for intermittent shorts to ground. If reading is not always infinite, replace pick-up coil.
2. Connect ohmmeter between both pick-up coil leads. Check for intermittent opens by flexing wires and connectors. If resistance is not 500-1500 ohms, replace pick-up coil.

Fig 1: Checking Distributor Pick-Up Coil

Courtesy of GENERAL MOTORS CORP.