Mixture Control Solenoid: Testing and Inspection

Feedback Solenoid Valve:

Feedback Solenoid Valve (FBSV) is installed in the carburetor float chamber cover. The ECU controls the air-fuel ratio of the main fuel metering circuit.

FBSV And SCSV Locations:

This is done by controlling the duty cycle of the FBSV based on the FBC sensor inputs. The longer the duty cycle "ON" time ratio, the leaner the air-fuel ratio.

TESTING PROCEDURE

1. The solenoid can be tested by locating and disconnecting the carburetor harness connector. Check the resistance of the solenoid coil between connector terminals 1 and 5.

Resistance: 54 - 66 ohm @ 20°C (68°F).

2. Check the solenoid for continuity (short) to ground between either terminal 1 or 5 and the solenoid body.

Continuity: Should Not Exist.


3. Connect jumper wires to the carburetor harness connector terminals 1 and 5. When power from a 12 Volt power source is applied a "Click" should be heard from the solenoid.

If the solenoid does not perform as described in the test procedures it will need to be replaced. Refer to FUEL SYSTEMS.


HARNESS TEST:

1. With the carburetor harness connector disconnected and the ignition switched on, connect a voltmeter to the harness connector terminal 5 and ground and measure the supply voltage.


Voltage: System Voltage.

1. Turn the ignition off disconnect the ECU connector and using an ohmmeter, check for continuity between carburetor harness connector terminal 5 and the ECU harness connector terminal 53.

Continuity: Should Exist.


1. Check for continuity (short to ground) to ground between carburetor harness connector terminal 5 and the ECU harness connector terminal 53.

Continuity: Should Not Exist.

If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed, road test the vehicle to confirm that the repair has corrected the problem.


If the same trouble reoccurs, it is possible that there is an intermittent failure of the component or the ECU. Check for looseness at all harness junctions and test for an intermittent failure.