Sequential PFI Engines
Measure resistance between the suspect cylinder test pin (from the Cylinder Balance Test) and test pin No. 37 at the breakout box. Refer to CAR - INDIVIDUAL INJECTOR RESISTANCE table. For no starts, choose any injector and measure resistance between that injector circuit test pin and test pin No. 37 at breakout box. Record resistance. Refer to CAR - INDIVIDUAL INJECTOR RESISTANCE table.
Remove breakout box and reconnect ECA. Service open/short in harness/connector. If okay, replace injector. Rerun QUICK TEST and Cylinder Balance Test.
For No Start: Service open in VPWR circuit.
5) Isolate Faulty Injector Circuit Turn key off. Install breakout box and disconnect ECA. Disconnect all injectors on suspect bank. With DVOM set on 200-ohm scale, connect one injector and measure resistance between test pins No. 37 and 58 or 59. Disconnect injector and repeat process for all other injectors. See CAR - INDIVIDUAL INJECTOR RESISTANCE table for specifications. If all injectors are within specifications, go to step 6). If injectors are not to specification, remove breakout box, reconnect ECA and injectors. Repair open or short in injector harness. If circuit is okay, replace injector. Rerun QUICK TEST.
6) Check Injector Drive Signal With key off and breakout box installed, connect ECA to breakout box. Use a non-powered 12-volt test light and the following connection procedure:
Connect test light between test pin No. 37 and the suspect injector(s) test pin at the breakout box.
Crank or start engine. A properly operating system is indicated by a test light that glows dimly. If light glows dimly, go to next step; except on sequential PFI engines. On sequential PFI engine, remove breakout box and reconnect ECA. Clean and test injectors. Rerun QUICK TEST and CYLINDER BALANCE TEST. If test light does not glow dimly, perform the following procedure:
- No Light - Check for 12 volts at test pins No. 37 and 57.
- Bright Light - Check injector circuit for shorts to ground. If system is okay, remove breakout box and replace ECA. Remove breakout box, reconnect all components and repeat QUICK TEST.
7) Fuel Pressure Problems: External Sources Pressurize fuel system as per procedure in step 1) of this test. Examine fuel system using the following procedures as applicable: