Carburetor Feedback Testing

Figure 4:

1. Using a Digital Volt Ohm Meter connect the positive lead to the Oxygen Sensor Checker terminal (Figure 4). Connect the negative lead to a good ground on the engine block.

NOTE: The oxygen sensor checker terminal has 2 electrical connectors. Connect the positive lead of the Digital Volt Ohm Meter to the connector with the shielded wire. If the voltmeter reads 0 Volts connect the positive lead to the other connector and recheck. If both readings are 0 volts then check the harness and connector of the JMS and oxygen sensor. If the harness and the connector is ok then the Oxygen Sensor is inoperative, replacement is necessary. The oxygen sensor voltage should vary continuously.

2. Connect a tachometer to the engine.

3. Start and warm the engine up to normal operating temperature.



4. Check the oxygen sensor voltage produced at 2500 RPM for 30 seconds. Note the maximum and minimum voltages produced.

NOTE: Carefully read the maximum and minimum voltages produced because the output voltage is fluctuating slowly in cycles.

5. Refer to the flowchart below for repair procedures.

NOTE: Voltage fluctuation is the difference from the maximum voltage produced minus the lowest voltage produced (high - low = voltage fluctuation).