High Energy Ignition (HEI) System - TBI

Wiring Diagram For EST:

The distributor reference signal comes from the ignition module and provides the ECM with RPM and crankshaft position information. If the wire becomes open or grounded the engine will not run, because the ECM will not operate the injectors. If the engine cranks but won't run, see DIAGNOSIS AND TESTING, CHART A-3.