FixVault

Idle Mixture

NOTE: Mixture adjustment is not a part of normal tune-up procedure, and should not be performed unless mixture control unit is replaced or vehicle fails emissions testing.

Start and warm engine to normal operating temperature. Using an exhaust analyzer, measure CO level. If CO level is not within specification, rotate CO adjuster screw clockwise to increase value or counterclockwise to decrease value. Adjuster screw is located on throttle body. See IDLE SPEED & CO LEVEL  table. Remove test equipment. Plug adjuster screw.

IDLE SPEED & CO LEVEL

Application Idle RPM (1) % CO Level
900
Non-Turbo 750-900 0.5-1.5
Turbo 850-900 0.9-1.6
9000
Non-Turbo 750-900 1.0-1.6
Turbo (2) (2)
(1) General specification. Check State Emission Standards.
(2) Idle speed, mixture, and CO level are controlled by ECM.