Quick & Easy Way to Test Fuel Injectors

Posted by Power Probe TEK on December 21st, 2016


Check out the video to see the Power Probe IV’s Fuel Injector mode in operation and how quickly you can now diagnose injector circuits.


If you have a car that won’t start or is misfiring, typically one of the first things to check is whether the fuel injectors are delivering fuel to the cylinders properly. Fuel injectors are essentially just electric solenoids that only provide fuel when they are commanded by the engine’s computer.

As with any electronically controlled system, there are many things that can go wrong that could prevent the fuel injector from working. The coil windings inside the injectors themselves could be shorted or open, they need a good source of power, and they need a good grounding signal from the ECM/PCM that is the proper duration. Any open or shorted condition in the injector wiring could also keep an injector from firing and you need to be able to detect those also.

There are a variety of currently used techniques and tools that can test a fuel injector or injector circuitry; however it usually involves using multiple tools and tests to check every aspect of the injector circuit. Complete testing could take quite a bit of time.

One powerful, time-saving feature included in the Power Probe IV is the dedicated Fuel Injector mode that can quickly and easily test the entire injector circuit with one simple probe connection.

One screen displays all the information you need; the voltage supplied to the injector, the ECM ground switching voltage, the inductive kick voltage from the injector windings, and the injector on-time in milliseconds. The LEDs at the top of the display also blink and the speaker tone sounds every time the injector fires, letting you know if it is operating consistently. Everything a scope would tell you without using a scope.


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