Fuel Injector: Testing and Inspection
***UPDATED BY TSB #F00193, JANUARY 11, 1993POWER SUPPLY CHECK
1. Disconnect injector harness electrical connector and turn ignition "ON".
2. Check for voltage at W/R wire terminal of harness side connector.
IGNITION "OFF" - 0 volts
IGNITION "ON" - 12 volts (battery voltage)
^ If no voltage is present, check main relay and wiring between main relay and injector harness connector.
RESISTANCE CHECK (OFF VEHICLE)
Individual Injector - Resistance Checking:
^ Check resistance between terminals on individual injectors, as shown in figure.
RESISTANCE......approx. 12 - 16 ohms
^ If resistance is not within the specified range, replace injector(s).
INJECTOR SPRAY PATTERN AND LEAKAGE CHECKING
NOTE: Before performing fuel system work, relieve system pressure.
1. Remove dynamic chamber and fuel rail with injectors. Leave fuel lines connected.
Leak Checking Fuel Injectors:
2. Secure injectors to fuel rail with wire, making certain that injectors are straight and cannot move.
Fuel Pump Test Connector:
3. Energize fuel pump by bridging terminals of yellow 2 pin test connector (connector B3-03) and turning ignition "ON."
4. One at a time, place injector nozzle ends into a suitable container. Energize injector momentarily by applying power and ground while observing spray pattern. A finely atomized, cone shaped mist of fuel should spray from injector nozzle.
WARNING: Fire hazard. Use appropriate connectors and long jumper wires. Do not create sparks near injectors or fuel container. Fuel mist is easily ignited.
5. Repeat step 4 for each injector.
6. Dry injector tips with a clean cloth and check for fuel dripping. After a minute or so, some wetting or a drop of fuel seeping from an injector nozzle is acceptable. More than one drip per minute is unacceptable.
7. Leaking injectors and injectors with poor spray patterns can sometimes be cleaned with a chemical fuel system cleaner. Use a cleaner designed for fuel injectors. Some brands of gasoline contain a cleaning additive for fuel injection systems. If clogged or leaking injectors are suspected, switching to one of these brands may help.
8. If cleaning does not restore normal injector operation, replace injector(s).