Carburetor

Testing Oxygen Sensor:

1. Warm up engine and run at idle.
2. Disconnect oxygen sensor wiring harness connector.
3. Connect voltmeter between oxygen sensor connector (oxygen sensor side) and ground.
4. Run engine at 4,000 rpm until voltmeter indicates approx. 0.7 volts.

Voltmeter Reading:

5. Increase and decrease engine speed suddenly several times. When speed is increased, check that voltmeter reads between 0.5 and 1.0 volts. When speed is decreased, check that voltmeter reads between 0 and 0.4 volts.
6. If not as specified, replace oxygen sensor. Connect oxygen sensor connector.

Self Diagnostic Checker Installed:

7. Connect self diagnosis tester to check connector and negative battery terminal.

NOTE: Do not ground test connector (Green:1-pin) during this test.

Self Diagnostic Checker:

8. Increase engine speed to between 2,000 and 3,000 rpm and check that monitor lamp flashes for 10 seconds. It should flash eight or more times in the ten second period. Disconnect diagnostic tester.

Oxygen sensor input voltage can be checked at ECU terminal 1A.