System Performance Test

1. Turn ignition switch on, ground trouble code test lead and observe code. If no trouble, code is displayed, refer to "Procedure 5."
2. Place transmission in park if equipped with automatic transmission, or neutral if equipped with manual transmission, and apply parking brake.
3. Disconnect purge hose from canister and plug, then disconnect bowl vent hose at carburetor.
4. Connect tachometer to engine (connect to distributor side of tach filter if used).
5. Disconnect mixture control (MC) solenoid and ground dwell lead.
6. Start engine and run at 3000 rpm. With throttle constant, connect MC solenoid and observe engine rpm.
7. If rpm drops less than 100 rpm, check MC solenoid and main metering circuit in carburetor.
8. If rpm drop is more than 100 rpm:
a. Disconnect ground from dwell lead.
b. Connect dwell meter (set to 6 cyl. scale) to MC solenoid dwell lead.
c. Set carb. on high step of fast idle cam and run engine for three minutes or until dwell starts to vary, whichever occurs first.
d. Return engine to normal idle and observe dwell.

NOTE: The oxygen sensor temperature may cool at idle causing the dwell to change from varying to a fixed indication between 10°-50°. If this occurs, run engine at fast idle to heat the sensor.

9. If dwell is fixed at 5°-10°, refer to "Procedure 1."
10. If dwell is fixed at 10°-50°, refer to "Procedure 2."
11. If dwell is fixed at 50°-55°, refer to "Procedure 3."
12. If dwell varies:
a. Check dwell at 3000 rpm.
b. If dwell is between 10°-50°, system is performing normally. Clear long term memory.
c. If dwell is not between 10°-50°, carburetor idle mixture must be adjusted. Refer to "Idle Mixture, Adjust" procedure.