Altitude Compensator Valve - Poor Driveability
Category Applicable Model/s Subject Bulletin No. 014/854 RX-7 (12A) ALTITUDE COMPENSATOR VALVE Issued 8/21/85
Revised
DESCRIPTION
An altitude compensator valve is attached to the 1981-1985 RX-7 carburetor to supply additional air into the carburetor at high altitudes (between 1640-4920 ft.) in order to lean the mixture for better driveability. If the altitude compensator remains open at low altitudes, the following driveability problems may occur:
^ Lack of acceleration, hesitation on acceleration
^ No power under load
^ Engine stumble, surge or bucking below approximately 3000 rpm
^ Rough idle
If the above driveability problems are encountered in RX-7 (12A), always check the altitude compensator as shown below before repairing the carburetor.
PARTS INFORMATION
PART NUMBER DESCRIPTION APPLIED MODEL
N249 20 770 Altitude Compensator Valve 1981-1985 RX-7
Altitude Compensator Valve:
CHECKING PROCEDURE
1. Remove the altitude compensator valve.
2. Blow through the valve from port A and
B. Check that:
^ Above 4920 feet - air into port A exits from port D and air into port B exits from port C.
^ Below 1640 feet - air does not pass. If not, replace the altitude compensator valve.
NOTE:
The operating specification of the altitude compensator valve will vary between 1640-4920 feet depending on atmospheric pressure.