High Altitude Compensator Solenoid Valve (Fed. Only)

HAC System:

PURPOSE
Leans fuel mixture when vehicle operates above approximately 3000 ft.

Component Locations:

LOCATION
Air passage is integral part of carburetor. Solenoid is on R.H. side of firewal.

OPERATION
When the vacuum/pressure sensor detects atmospheric pressure of 670 mmHg (26.38 in.Hg) or less, the EFC System control unit opens the high altitude compensator (HAC) solenoid valve to correct for the richer air/fuel ratio at high altitudes. The HAC valve then permits additional air into the carburetor auxiliary air passage near the main metering passage to lean out the mixture.