Fuel Injector: Testing and Inspection

INJECTOR
The injectors inject fuel to cylinders according to the signal, suitable to engine condition, from ECM. The ECM drives the injectors by electric current driving mode.

The basic fuel amount is performed by the mapping value based on the air amount and engine rate, and the fuel amount is corrected in the case of fuel amount correction (Air-fuel ratio control signal, fuel evaporative emission gas control, learning increase of the fuel amount, warm-up control, catalytic heating control, fuel amount control in deceleration, idle control, fuel amount increase in full load, fuel increase in acceleration and restarting).

The fuel injection is controlled under unavailable state for safety purpose when engine rpm reaches the appropriate engine speed.

Circuit Diagram (Injector):

Harness Connector:

INJECTOR INSPECTION



1. Measure the resistance of the injectors between the terminals using an Ohmmeter.
Resistance: 13.8 - 15.2 Ohms [at 20 °C (68 °F)]

2. If the resistance is not within specifications, replace the injector.

TROUBLESHOOTING HINTS
1. If the engine is hard to start when hot, check for fuel pressure and injector leaks.
2. If the injectors do not operate when the engine is cranked, then check the followings:
- Defective power supply circuit to the ECM, faulty ground circuit
- Defective control relay
- Defective Crankshaft Position (CKP) Sensor or Camshaft Position (TDC) Sensor

3. If there is any cylinder whose idle state remains unchanged when the fuel injectors are cut one after another during idling, check for the following items about that a cylinder.
- Injector and harness
- Ignition plug and high tension cable
- Compression pressure

4. If the injection system is OK but the injector drive time is out of specification, check for the following items.
- Poor combustion in the cylinder (faulty ignition plug, ignition coil, compression pressure, etc.)
- Loose EGR valve seating

Harness Inspection Procedures: