7 terminal HEI module

[john spears]

dzorde asked about the 7 term HEI module. Yes this can easily be fitted to a
variable reluctance distributor to set up the proper signals to and from the
ECM. The BYPASS line is used to determine which is controlling when the coil
fires; the HEI module or the ECM. When cranking, the HEI module is
controlling the ign. coil and you are firing on base timing. When the ECM
determines that the engine is running, (refered to as KRPMUP) it sends a
signal down the bypass line (bypass goes high), at this point the ECM takes
over the function of determining when to fire the coil.    In other words
when bypass is low, the ignition module controls spark, and when bypass goes
high the ECM controls spark. The reference terminal is the squared rpm
signal for the ECM (derived from the rotating reluctor) and the EST line is
the actual coil firing command signal from the ECM.

               John Spears
Speartech Fuel Injection Systems