Diagnostic Tools
- The Closed Loop Emission Control system does not require special tools for diagnosis. A dwell meter, tachometer, test light, ohmmeter, digital voltmeter with 10 megohms impedance (minimum), vacuum pump, vacuum gauge and jumper wires are the only tools necessary for diagnosis.
- A test light, rather than a voltmeter, must be used where indicated in diagnostic chart. A dwell meter is used to measure the time that the vacuum control solenoid is on or off.
- Set dwell meter on 4-cylinder scale.Connect positive lead of dwell meter to Bright Green connector in Closed Loop Wiring harness and negative lead to ground. The scale on the meter will show condition of the circuit.
- When needle is at 10°, this indicates a rich mixture. A lean mixture will read near 54°. A varying needle indicates that system is in closed loop.
NOTE:
If engine performance changes when dwell meter is connected to system, remove dwell meter and use another type. A few brands are not compatible with the electronic emission system.