How to test fuel injectors with a multimeter
Content
In my article below, I will tell you how to test a fuel injector with a multimeter.
Fuel injectors are vital for controlling the air-fuel ratio. A bad fuel injector can cause problems such as cylinder misfires, poor engine performance, harmful emissions, and poor fuel economy due to impurities in the fuel. It is very important to check the fuel injectors regularly.
Quick steps to test fuel injectors with a multimeter:
- Find the fuel injector
- Lift up the cover that protects the two fuel injector pins.
- Set your multimeter to resistance mode
- Place two multimeter leads on two pins
- Check the resistance with the calculated value of the vehicles resistance in manual mode.
I'll go into more detail below.
3 steps to test fuel injectors with a digital multimeter
If you think that checking a fuel injector is a difficult task, you are deeply mistaken.
With three simple steps, you can test your fuel injectors accurately. In this section, I will explain these three steps in detail. So let's get started.
Step 1 - Fuel Injector Identification
First, you must find the fuel injector.
Most people have difficulty identifying a fuel injector. To be honest, finding a fuel injector is very easy. Open the hood. Then take the car's owner's manual. Usually in a car, the number of fuel injectors is equal to the number of cylinders. This means that if your car has four fuel injectors, it has four cylinders.
The fuel injectors are located in the intake manifold. Confirm this from the vehicle owner's manual.
These injectors are connected to the fuel rail. So, remove the fuel rail from the engine. Now you can see the fuel injectors on the fuel rail.
How to remove fuel injectors from your car
If you are planning to test the injectors, the first thing you need to do is learn how to remove them from your vehicle. Although it is possible to check the fuel injectors without removing them from the engine, the fuel rail is easy to separate. So here is how you can do it.
1: First, make sure the car is cold. Using a hot vehicle may cause a fire due to fuel leakage. Then disconnect all fuel injector connectors. (1)
2: Loosen the bolts connecting the fuel rail and fuel line. If there are hidden bolts, be sure to loosen those too.
3: Finally, remove the fuel rail.
Step 2 - Setting Up the DMM
To test the injectors, set the multimeter to test for resistance. Most multimeters have an Ω symbol in the selector switch area. So, turn the switch to the Ω symbol.
Then insert the black wire into the COM port. And insert the red wire into the port that displays the Ω symbol. Your multimeter is now ready for the resistance test, also known as resistance mode.
Step 3 - Compare Resistance Values
Now remove all covers protecting the two pins of each fuel injector.
Place the red wire on one pin and the black wire on the other pin. Check the multimeter and record the resistance value in ohms. Apply the same process to other fuel injectors.
Then check your vehicle owner's manual for the calculated resistance value. If you can't find it in the manual, do a quick web search or contact the manufacturer. Now compare the design value and the test value. If the two values match, the fuel injector is working properly. If the values show a noticeable difference, you are dealing with a faulty fuel injector. (2)
Keep in mind: If the design value is 16.5 ohms, the test value should be 16-17 ohms.
The Importance of Fuel Injectors
Before starting the testing process, we must understand why we are doing this injector test. Here is a brief explanation of fuel injectors and their importance.
Fuel injectors primarily act as a device that delivers pressurized fuel to the engine. After a while, these fuel injectors can fail or stop working permanently. The main reason for this is impurities in the fuel. In addition, mechanical and electrical problems can be the cause of a failed fuel injector.
Either way, a faulty fuel injector can have a very negative effect on your vehicle. A damaged fuel injector can affect the overall performance of your engine and your vehicle. Therefore, maintaining fuel injectors in top-notch condition is critical.
Take a look at some of our articles below.
- How to check the fuel level sensor with a multimeter
- How to test a capacitor with a multimeter
- Multimeter symbol table
Recommendations
(1) fuel – https://www.sciencedirect.com/journal/fuel
(2) Internet – https://www.britannica.com/technology/Internet
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