Computers and Control Systems: Tools and Equipment

Diagnosis of the closed loop emission system requires the use of these tools and equipment:

1. Tachometer -- To monitor manifold engine speed.
2. Dwell meter -- Used to indicate vacuum control solenoid circuit performance conditions. Connect positive lead of dwell meter to bright green connector on Closed Loop wiring harness and negative lead to ground. Set meter on 4 cylinder scale. Scale on meter will show condition of circuit. A 10° reading on scale indicates a rich mixture, while a 54° reading is an indication of a lean mixture. A varying dwell indicates that system is in closed loop operation. Although most dwell meters can be used, if one causes a change in engine operation, it should not be used for diagnosis.
3. Vacuum Gauge -- To monitor manifold engine vacuum.
4. Vacuum Pump -- To check pressure or vacuum sensors and vacuum operated valves.
5. Digital Voltmeter & Ohmmeter/Voltmeter J-29125-A or equivalent -- To measure ohms and voltage of circuits.