Anti-AFTERBURN System: Operation

During deceleration or gear changes (throttle closed with high RPM), high manifold vacuum is present in intake manifold. This causes excessive fuel to be drawn into intake manifold. Since throttle is closed, inadequate air is present to promote efficient combustion.

When conditions indicate anti-afterburn may be required, control solenoid is energized by ECU. This allows manifold vacuum to pass into upper chamber of anti-afterburn valve. Valve senses changes in manifold vacuum caused by deceleration and gear changes and allows filtered air from air cleaner to be drawn into intake manifold. This provides adequate air for continuation of the combustion process.