Deceleration Valve

This valve is used on 2.8L engines to prevent backfiring in the exhaust system during deceleration. This valve is normally closed, but opens when sudden deceleration increases vacuum to a point of overcoming internal spring pressure.

This allows additional air into the intake manifold to prevent overly rich mixtures from entering the combustion chambers. Air trapped in the chamber above the vacuum diaphragm will bleed, at a calibrated rate, through the delay valve portion of the integral check and delay valve.

This reducing vacuum acts on the diaphragm. When the vacuum load on the diaphragm matches spring load, the valve assembly closes. This shuts off air to the intake manifold.