Electronic Fuel Control Computer Test

4 Cylinder Engines
1. Disconnect and plug vacuum hose from computer. Using a suitable vacuum pump, apply 14 inches Hg vacuum to the computer.
2. With engine at normal operating temperature, ensure carburetor switch is not grounded.
3. Connect a tachometer to the engine, and increase engine speed to 2000 RPM. Connect a voltmeter to the green solenoid output wire going to the carburetor. Do not disconnect electrical connector from harness. Disconnect electrical connector at the oxygen sensor and connect a jumper wire to the harness end. Connect the other end of the jumper wire to a ground.
4. A minimum of 50 RPM increase in engine speed should be noted and voltmeter should indicate more than 10 volts.
5. Hold wire with one hand and with the other hand touch battery positive terminal. Engine speed should decrease a minimum of 50 RPM. Voltmeter should now indicate less than 5 volts. If readings obtained are incorrect, replace computer.