Fuel Injectors, Checking: Notes
The following test procedure is used to diagnose all fuel injectors.
Special tools and workshop equipment required
- Multimeter.
- Diode test lamp (12V).
- Wiring diagram.
Test requirements
- The fuses OK.
- The Engine Speed (RPM) Sensor -G28- is OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- Vehicles with automatic transmission, shift selector lever into position "P" or "N".
- A/C switched off.
- Ground connections between engine/transmission/chassis OK.
- Ignition switched Off.
-- Observe safety precautions.
-- Observe rules for cleanliness.
Test procedure
-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK
Start diagnosis
-- Disconnect the Fuel Injector -- electrical harness connectors from Fuel Injectors -N30, N31, N32, N33-.
When the Ignition is Switched to the On position; The fuel injectors receive voltage to terminal 1 along with the fuel pump getting activated for 2 seconds to build up the pressure in the fuel system.
-- Switch the ignition ON.
-- Using a Multimeter, Check the Fuel Injectors -N30, N31, N32, N33- electrical harness connector terminals 1 to Engine ground for voltage.
Specified value: Battery Voltage
-- Switch the ignition Off.
Continue test according to the following table:
| Value | Cause | Test |
|---|---|---|
| If the specified value was not obtained: | Open or shorted circuit | Checking wiring |
| If the specified value was obtained: | Check resistance and reference signal circuit | Checking internal resistance |