Fuel Injector Circuit Tests

Check Fuel Injector Operation - Using a stethoscope, ensure that injector operating sound (clicking) is present while engine is cranking. If operating sounds are not heard, go to next step. If operating sounds are heard, verify fuel pressure. See FUEL PRESSURE under FUEL SYSTEM.
Check Fuel Injector Power Circuit - Turn ignition off. Disconnect each fuel injector harness connector. Check voltage on each injector harness connector. At least 10 volts should be present. If voltage is as specified, go to next step. If voltage is not as specified, repair harness or connectors as necessary. See appropriate wiring diagram in WIRING DIAGRAMS article.
Check Fuel Injectors - Check resistance between connector terminals of each fuel injector. Resistance should be 11-12 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace injector(s).
Check Voltage Between ECM Connectors & Fuel Injectors - Reconnect fuel injector harness connectors. Turn ignition on. Check voltage between listed ECM connector terminals and ground. See the FUEL INJECTION & ECM HARNESS VOLTAGE TESTING table. Voltage reading should be at least 5 volts. If voltage is as specified, go to next step. If voltage is not as specified, repair or replace harness or connectors as necessary.
Check ECM Ground Circuit Resistance - Disconnect ECM 26-pin harness connector. Check resistance between harness connector terminal No. 24 and ground and between harness connector terminal No. 25 and ground. If resistance is greater than zero ohms, repair harness or connectors between ECM and ground. Inspect ECM connector terminal. If ECM connector terminal is okay, replace ECM.

FUEL INJECTION & ECM HARNESS VOLTAGE TESTING

ECM Terminal No.

Wire Color

Engine Cylinder No.

13 ⁽¹⁾

(WHT)

12 ⁽¹⁾

WHT/BLK

11 ⁽¹⁾

WHT/RED

26 ⁽¹⁾

WHT/BLU

1 ⁽²⁾

WHT/GRN

12 ⁽²⁾

WHT/YEL

⁽¹⁾	Yellow ECM 26-pin connector.

⁽²⁾	Yellow ECM 22-pin connector.