Fuel Injector: Testing and Inspection

Perform the following test procedure using a suitable digital volt/ohmmeter, referring to Fig. 3 for terminal identification.

Fig. 3 Bosch Motronic Electronic Engine Control System Terminal Identification:

1. Perform procedure described under ``Output-Periphery Test'' for fuel injectors. If audible Tick-Tock sound is not heard, proceed as follows:
a. With ignition switch in run position, check for 12 volt reading from main relay terminal 87 to distribution point 45 and to the fuel injectors.
b. Check for continuity from ECU terminal 14 to fuel injectors.
c. Check fuel injector solenoid winding resistance at each injector. Reading should be 15.55-16.25 ohms.

Fig. 9 ECU Injection Signal:

2. If test steps 1a through c of this procedure prove good, and malfunction still exists, proceed as follows:
a. Connect a suitable oscilloscope to one fuel injector. Signal should be as shown in Fig. 9.
b. If signal is not as specified, check all wires and connections to fuel injectors and injector spring plugs.
c. If all test prove good, and malfunction still exists, replace ECU and retest.