Bronco L6-300 4.9L VIN Y 1-bbl (1983)
Air Injection Check Valve: Description and Operation
Anti-Backfire Gulp Valve
Fig. 73 Anti-backfire gulp valve
The anti-backfire gulp valve, used on some vehicles, routes a portion of thermactor air to the intake manifold and is activated by intake manifold
vacuum signal, Fig. 73. This valve is located downstream from the air bypass valve and functions only during periods of sudden decrease in manifold
pressure.
