Fuel Injector: Testing and Inspection

Fig. 16 Checking power feed circuit:

TEST 1, POWER FEED CIRCUIT CHECK

1. Connect test light between red wire at injector, Fig. 16, and clean underbody ground, then turn ignition switch to RUN position and observe test light.
2. If light illuminates, proceed to TEST 2.
3. If light does not illuminate, repair open in power feed circuit to injector.



TEST 2, INJECTOR FUNCTIONAL CHECK

1. Connect one end of jumper wire to clean underbody ground and turn ignition switch to RUN position.
2. Using jumper wire, ground tan wire at injector, then listen and feel for injector click.
3. If injector clicks, proceed to TEST 3.
4. If injector does not click, replace injector and repeat test.

TEST 3, CONTROL CIRCUIT CONTINUITY CHECK

1. Using ohmmeter, check for continuity between injector tan wires and wires connected to pins 58 and 59 at ECA.
2. If there is continuity, problem is not in injectors.
3. If there is no continuity, repair open in ECA control circuit.

FUEL INJECTOR FUNCTIONAL TEST

1. Run engine until it reaches operating temperature.
2. With engine at idle, disconnect and reconnect each injector, noting any change in idle speed.
3. If idle speed drops when injector is disconnected and returns to normal when injector is reconnected, injector is satisfactory.
4. If no change occurs in idle speed or quality when fuel injector is disconnected, a faulty injector is indicated.