Test Description

Test Number 1)  A "Service Engine Soon" light "ON" is a basic test to determine if there is a 12 volt supply and ignition 12 volts to ECM. No ALDL may be due to an ECM problem and CHART A-2 will diagnose ECM. If TPS is over 2.5 volts the engine may be in the clear flood mode which will cause starting problems. If coolant sensor is below -30°C, the ECM will provide fuel for this extremely cold temperature which will severely flood the engine.

Test Number 2)  Voltage at spark plug is checked using spark tester tool ST-125 (J 26792) or equivalent. No spark indicates a basic ignition problem.

Test Number 3)  While cranking engine there should be no fuel spray with injector disconnected. Replace an injector if it sprays fuel or drips like a leaking water faucet.

Test Number 4)  Use an injector test light like J 34730, BT-8329A or equivalent, to test injector circuit. A blinking light indicates the ECM is controlling the injector.

Test Number 5)  This test will determine if there is fuel pressure at the injector and that the injector is operating.