Computers and Control Systems: Tools and Equipment

The closed loop emission control system requires the use of the following tools and equipment for accurate system diagnosis:
1. Tachometer. Either a crankshaft harmonic balancer revolution pickup type or an electronic coil trigger signal pickup type can be used.
2. Dwell meter. The dwell meter is used to indicate the performance conditions of the mixture control solenoid circuit. Connect the positive lead of the dwell meter to the bright green connector in the computer wiring harness near the mixture control solenoid, and the negative lead to ground. Place meter on the 6 cylinder scale. The meter scale will show the condition of the mixture control solenoid circuit. If meter needle is on 10°, this indicates a rich mixture condition. A lean mixture will read near 54°. A varying needle (needle fluctuation) indicates that the system is in the closed loop operation mode. Although most dwell meters will work for this system test, some dwell meter units may cause a change in engine operation when connected to the mixture control solenoid ``Dwell'' lead. If this occurs, the dwell meter should be replaced with another unit for this test.
3. Vacuum gauge. The vacuum gauge will monitor engine manifold vacuum.
4. Vacuum pump tool No. J23783 or equivalent. The vacuum pump will check pressure or vacuum sensors and vacuum operated valves.
5. Voltmeter and ohmmeter. Use digital volt-ohmmeter J-29125-A or equivalent. The volt-ohmmeter will measure the closed loop system voltage.
6. Jumper wires. The jumper wires will be used to bypass a circuit and to be inserted between special connectors to permit access to the terminal connectors for circuit checking.
7. Test light.
8. Oxygen sensor wrench tool No. J29533 or equivalent. This wrench will be used to remove and install the oxygen sensor.