Tachometer Test

With engine running, measure voltage at tachometer input connector White wire. Voltmeter should indicate 1-10 volts and should vary with engine RPM. If voltmeter reading is not as specified, check White wire for open circuit. If White wire is okay, Computer Controlled Coil Ignition (C(3)I) system is faulty. If voltage reading is correct, replace tachometer or IPC, as necessary.