All motor vehicle owners know how important it is to keep their vehicle in good working order and to carry out regular checks. An essential part of a vehicle’s electrical system consists of the spark plugs.
Spark plugs are responsible for transferring electrical energy to the cylinders, where they initiate combustion. If they are worn, damaged, or show signs of malfunctioning, this may be the cause of an engine that is not running properly or consuming more gas than necessary.
Fortunately, it is possible to test a spark plug easily using a simple tool: the multimeter. Multimeters are often sold at DIY stores and are relatively affordable, making them ideal for small automotive jobs.
If you want to learn how to test a spark plug using a multimeter, here’s a step-by-step guide on how to do it.
Step 1: Preparation of the material
Before you begin, you’ll need to make sure you have all the necessary materials on hand:
- A multimeter
- A needle-nose pliers
- A spark plug probe
Remark : It is important to use a special spark plug probe suitable for your type of spark plug. If you’re unsure which probe to use, be sure to check your vehicle’s manual for the correct size.
Step 2: Remove the spark plug
The first step is to locate and remove the spark plug to be tested. This usually involves extracting the spark plug using a spark plug wrench and gently unplugging it.
Step 3: Connect the multimeter
Before you start testing, you will need to connect the multimeter to the spark plug. To do this, take the candle probe and connect it to the multimeter. Then connect the probe to the spark plug. The multimeter will then be ready to perform tests.
Step 4: Set the multimeter
You will then need to set the multimeter to be configured to read spark plug voltage. Most modern models have an automatic function that makes tuning much easier. You can also do this manually by choosing the “ohm” mode and setting the slider to an appropriate range for your candle type.
Step 5: Read the results
Once the multimeter is set, you can now take readings. Press the test button and the multimeter will display the reading, indicating the resistance of the spark plug. A reading between 0.8 and 1.2 ohms is normal for most spark plugs.
If you get a reading below 0.8 ohms, the spark plug is too hot and needs to be replaced. A reading above 1.2 ohms indicates that the spark plug is too cold and should also be replaced.
Step 6: Clean the spark plug
If the reading is between 0.8 and 1.2 ohms, you may need to clean the spark plug to improve its performance. Use a specific spark plug cleaner (available at most auto stores) and follow the instructions that come with the product to prepare it. Once the product is applied, wait a few minutes and then try to read the voltage once more on the multimeter.
By following these steps, you will be able to easily test the spark plug on your vehicle and identify any problems before they affect engine operation. Always remember to follow the safety instructions and not directly touch the spark plug when it is plugged into a multimeter or other electrical device.
