Regal V6-231 3.8L Turbo VIN 8 4-bbl (1983)
Some diagnostic differences between the single board and the two board ECM's will result in the functions of some ALCL scan tools being unusable, the
changes are in the Mixture Control Solenoid duty cycle (dwell) readings, oxygen sensor voltages, and knock retard modes.
Mixture control duty cycle readings when using the ALCL tool will read 0~ at idle and 60~ at part throttle, if these readings are obtained the ALCL tool
is unusable in this mode and will require the use of a standard external dwell meter to obtain the correct dwell readings.
Oxygen sensor voltages up to 1.4 volts may be seen on the ALCL tool when a full rich exhaust condition exists. Previously 1.0 volt maximum readout
was seen.
Knock retard mode will provide readings on the ALCL tool, however, direct degrees of retard will not be indicated. Counts will be seen indicating the
electronic spark control is operating, but these figures are not direct degrees of timing.
Figure 1 provides revised ECM terminal voltages used with the single board ECM.
Figure 2 is the revised electrical EFE DIAGNOSTIC ECM application.
