B Series Truck 2WD L4-2555cc 2.6L SOHC (1987)
Air/Fuel Mixture: Adjustments
Air/Fuel Mixture
Fig. 15 Connecting Dwellmeter To Check Connector.
Before adjusting idle speed or mixture, be sure the ignition timing and spark plugs are in normal operating condition. Turn off all lights and other
unnecessary electrical loads.
CHECKING IDLE MIXTURE
1.
Warm up engine and run it at idle.
2.
Connect a dwellmeter (90 degrees, 4 cylinders) to the YG wire in the check connector Fig. 15.
NOTE: The check connector is near the No. 3 ACV and read valve case assembly.
Fig. 16 Idle Mixture Dwell Reading Range (Preferred For Adjustment
3.
Check the idle mixture (duty) at the specified rpm (800-850 rpm).
Idle mixture: 27-45 degrees Fig. 16.
4.
If the idle mixture is not within specifications, check the oxygen sensor, the feedback control unit, and the wiring between the oxygen sensor and
the feedback control unit. If they are satisfactory, adjust the idle mixture.
