How to Test the Two Wires of an EFI Diesel Fuel Injector?
3 Answers
Connect the two probes of the test lamp to the connector of the fuel injector harness and start the engine. If the test lamp flashes at a certain frequency, it indicates there is no fault. If the test lamp does not light up or remains constantly lit without flashing, it indicates that the fuel injector is malfunctioning and there is a fault.
When testing the two wires of an electronically controlled diesel injector, I typically use a digital multimeter. First, turn off the engine and disconnect the negative battery terminal for safety, then unplug the injector connector. Next, set the multimeter to the resistance measurement mode and measure the resistance between the two wires; the normal range is generally between 10 to 20 ohms. If an infinite resistance is detected, it indicates an open circuit, while a resistance close to zero suggests a possible short circuit. After that, reconnect the battery and start the engine without ignition, then switch to the voltage measurement mode to test the line voltage; you should observe a pulse signal of approximately 12V. If there is no voltage or an abnormal signal, it indicates a control circuit malfunction. I always remind myself that diesel systems involve high pressure, and improper operation may damage components. It's best to proceed under experienced guidance or directly visit a 4S shop for inspection to avoid causing more severe electronic system issues. Additionally, excessive carbon buildup on the injector can affect test results, so regular cleaning is essential.
I've been in the auto repair business for years and have dealt with numerous common rail diesel injector issues. Testing those two wires is straightforward: grab a multimeter, set it to resistance mode, and measure the resistance between the wires. A reading between 10-20 ohms is normal – too high indicates an open circuit, while too low suggests a short. Next, perform a voltage test: start the engine without ignition and check for a pulsing voltage around 12V. If there's no voltage, inspect the fuse or relay for burns. After testing injectors, I always check related circuits like ECU connections as preventive maintenance. Remember, diesel engines are sensitive – improper handling can damage electronic modules, so I always advise beginners to wear insulated gloves. Safety first! When in doubt, consult a professional technician to avoid costly repairs from compounded issues.
