Fuel Control
Carburetors used include the Holley 6280 2-Barrel and the Rochester Quadrajet 4-Barrel used on police models only. Both models are equipped with an electronically-operated oxygen feedback solenoid. This solenoid meters the main fuel system of the carburetor and operates in parallel with the conventional fixed main metering jets. The computer controls the operation of the solenoid with electrical signals, in response to input from data sensors. See Fig 1 and Fig 2 .
When de-energized, the solenoid main metering orifice is fully uncovered, providing the richest mixture for any given airflow.
When the solenoid is energized by the computer, the solenoid main metering orifice is fully sealed. This solenoid position offers the leanest mixture within the carburetor for any given airflow.
Main system fuel is regulated between rich and lean mixture conditions by controlling the amount of time that the solenoid is energized and de-energized. The computer controls the duration of time that solenoid is energized in comparison to total time of solenoid operation.
This duration of time is determined by engine operating conditions and/or oxygen sensor signals. In this manner, the ideal air/fuel ratio can be constantly maintained.