Caution: When performing maintenance procedures in the engine compartment with the engine running, exercise extreme caution - try not to touch moving components (drive belts, fan impeller, etc.) and do not allow hair or clothing to get caught in them.
Analysis of the test results
All injectors click properly
1. If all injectors click properly and, nevertheless, there are suspicions of malfunctions in the fuel system, continue diagnostics.
2. Check the pressure characteristic of the fuel pump (see below).
3. Check the ignition system. Disconnect (and reconnect) the high-voltage wires from each spark plug one by one with the engine idling, and try to locate the faulty cylinder based on the absence of a disruption in the stability of the revolutions.
4. Remove the fuel injector for the suspect cylinder and place it on a workbench (the fuel line assembly can be removed). To check the injection pattern, connect the fuel supply line to the injector and briefly apply 12 V DC to its terminals (grounded through the injector body): a cone-shaped jet of fuel should be ejected through the valve nozzle. A faulty injector must be replaced.
One or more injectors do not click
1. Prepare a special test lamp. Turn off the ignition and disconnect the wiring from the injector to be tested. Connect the test lamp to the contact connector of the injector wiring harness and start the engine: the lamp flashes to confirm that the control voltage is supplied to the injector correctly.
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2. If no power supply faults are detected, measure the injector resistive resistance. Compare the measurement result with the Specifications (for engines with normal suction, the nominal value is within the range of 13÷16 Ohm, at 20°C, for turbocharged engines, the required range is 2÷3 Ohm [at the same temperature]).
3. If the test lamp shows signs of a control voltage supply failure, the condition of the corresponding electrical circuit should be checked. Disconnect the negative cable from the battery.
Warning! If the car stereo system is equipped with a security code, make sure you have the correct combination to activate the audio system before disconnecting the battery! Disconnect the test lamp from the injector. Also disconnect the wiring from the PCM. Check the condition of the wiring in the circuit section between the PCM and the injector: the resistive resistance between the corresponding connector contacts should be about 5 ohms. If the test results are negative, make the necessary restorative repairs to the wiring.
4. If the circuit is OK, then there is an internal PCM failure and the control module must be replaced.