Fuel Injector: Testing and Inspection

Fig. 23 On vehicle inspection, injectors.:

1. Using a mechanic's stethoscope, check operation of injectors from idle through acceleration. Regular operating noises (clicks) should be heard throughout operating ranges. If clicks are not heard, check for continuity in wire from trailing coil terminal to U terminal of control unit connector. If continuity does not exist, check for open circuit or blown EGI main fusible link. Turn ignition switch On and listen for click at main relay. If main relay does not click, check for 12 volts at main relay connector No. 2 (BW wire).

Fig. 25 Fuel injection leakage testing.:

2. Disconnect injector connector and connect suitable ohmmeter to injector terminals. Observe ohmmeter. Resistance should be 1.5-3.0 ohms. If resistance is not as specified, replace injector.
3. Check injectors for fuel leakage as follows:
a. Remove dynamic chamber as outlined under System Servicing.
b. Loosen delivery pipe attaching bolts, then attach delivery pipe to injectors with wire Fig 25. Delivery pipe should be firmly attached to injectors so that no movement of injectors is possible.

Fig. 30 Connecting jumper wire to fuel pump short circuit terminal.:

Fig. 39 Installing injector checker tool #49 9200 040:

c. Turn ignition switch On, then connect jumper wire to fuel pump short circuit terminal, Fig. 30. Observe injector. No fuel should leak from injector nozzles. If leakage is evident, replace nozzle. A small amount of leakage after approximately 5 minutes of testing is acceptable.
4. Check injection fuel volume as follows:
a. Perform steps 3a and 3b as outlined previously.
b. Connect and clip suitable vinyl hose to injector, then place other end of hose in a graduated cylinder.
c. Connect injector checker tool 49 9200 040 or equivalent to injector, Fig. 39.
d. Turn ignition switch On, then connect jumper wire to fuel pump short circuit connector, Fig. 30.
e. Connect checker tool electrical leads to battery, then measure fuel volume released into graduated cylinder. Fuel volume delivered should be 149-197 cc within a 15 second interval.