Fuel Control

An acceleration enrichment control unit has been introduced to the system to replace the speed relay. It also has a circuit for cold engine acceleration enrichment. Air/fuel enrichment occurs only when coolant temperature is below 140°F (60°C) and sensor temperature is below about 480°F (250°C) (during warm-up).

If either temperature is exceeded, there will be no acceleration enrichment. If the throttle is opened, the control unit will be activated at a throttle angle of 1° or 7°. The control unit puts out a voltage signal to the oxygen sensor control unit, which increases the duty cycle to 75% for about 2.5 seconds. Air/fuel mixture will be enriched during this time.

The DITC control unit stabilizes idle speed whenever accessories are turned on which might cause a fluctuation in idle speed. It does this by advancing or retarding the ignition timing.