How To Test Spark Plug With Multimeter

Suppose that you are getting ready to travel, but after packing your belongings into your car, the engine won’t start. Defective spark plugs are probably to blame for this. If you’re like most people, you probably consider the spark plugs in your car to be maintenance items that you should only consider when it’s time for a tune-up.

It worsens as a result of continuous pollution and overheating, and you may have trouble starting your automobile, misfiring engines, or poor fuel economy. In this blog post, we’ll learn, how to test your spark plugs with a multimeter.

Let’s get right in.

What Is A Spark Plug And Why Does It Need To Be Tested?

Spark plugs are an important part of any gasoline engine. The spark plug can be described as an electrical spark-igniting component installed inside the top of a piston inside the combustion engine. By eliminating thermal energy from the combustion chamber that is not needed, it warms the engine’s cooling system.

The two main tasks of a spark plug are to ignite the mixture of air and fuel and to keep track of the piston electrification process.

It’s necessary to replace your spark plugs as soon as possible. Engine damage or even full engine failure might result from waiting too long. Hence, to keep your engine operating smoothly, make sure to keep an eye on your spark plugs and inspect them frequently

Safety tips when testing spark plugs

• Be careful not to get your fingers on the connections of the spark plug.
• While handling spark plugs or doing testing, wear safety eyewear.
• Ensure that the engine is turned off and cooled before beginning the test.
• Unplug the multimeter before attaching the probes to the spark plug’s terminals.
• Use only operating spark plugs; do not use broken, fouled, or defective plugs.
• Be sure you use plugs designed particularly for your engine.
• Dropping a spark plug to the ground might harm it, so avoid doing so.

How to test Spark plug with Multimeter

Each internal combustion engine’s ignition system is incomplete without the spark plug, which must be in excellent condition for the machine to function properly. You may test your spark plug with a multimeter to determine whether it is defective if you think it could be. To use a multimeter to test a spark plug. Step by Step Procedure to test spark plug with a multimeter:

1. Wipe each wire, with a cloth then look for physical damage like cuts, scorch marks, or boot attraction between the boot, spark plug, and coil.
2. When the car has started, look for electrical sparks around the wires.
3. Unplug the fuse for the fuel pump in fuel-injected autos.
4. If there is no visible damage, check the spring clips that hold the wires within the distributor cap.
5. With carbureted engines, the fuel pump and piping must be kept separate.
6. Once the fuel in the system has all been burnt up, start the engine.
7. The spark plug has to be taken out. With plug-in cars with coil packs, unscrew the installation bolt and remove the coil.
8. The spark plug has to be taken out. With plug-in cars with coil packs, unscrew the installation bolt and remove the coil.
9. In an older engine, pull the plug wire away from the spark plug. If you use spark plug pliers, both you and the wire will find this much simpler.
10. Remove the spark plug from the cylinder head. On the multimeter, set the ohms setting. the distance between the probes’ resistance.
11. Using a digital or analog multimeter, determine each spark plug wire’s resistance to verify if it conforms with the manufacturer’s requirements.
12. Ensure there is no resistance in the probes to ensure you get an accurate reading. Attach one lead to the center electrode and the plug’s end terminal.
13. Measure the wire by inserting probes on either end of the wire lead, making sure they meet the electrical components, then test and reconnect each wire to the appropriate scale. Before moving on to the next wire, you can return the wire to the car if the measurement is within the manufacturer’s standards.

Note:

A good spark plug should have resistance between 500 and 3000 ohms. Values lower than 5000 ohms are acceptable when the plug ages. But, if the plug’s resistance value exceeds 5000 ohms, it must be changed.

Remember that a broken spark plug might result in an engine misfire, therefore it’s crucial to check them and replace them as necessary. Moreover, be sure to look up the precise resistance range for your vehicle’s spark plugs in your owner’s handbook.

Causes Of a Bad Spark Plug

Overheating

If your spark plugs become too hot, they may malfunction and break down. This may be caused by a number of factors, including overheating the engine, using the incorrect spark plug type for your car, or having a faulty spark plug.

Oil fouling

 If oil accumulates on your spark plugs, it may result in misfires and eventually cause them to fail. An oil leak, an excessively high fuel mixture, or poor valve clearance are all potential causes of this.

Carbon deposits

Carbon deposits can build on your spark plugs over time and prevent them from igniting correctly. Inadequate combustion, excessive idling, or utilizing the incorrect fuel type can all contribute to this.

Damaged

 Your spark plugs may not fire correctly if they sustain damage. Physical damage, such as running over a pothole, or electrical damage, like a voltage spike, can both contribute to this.

It’s crucial to have your spark plugs examined by a trained mechanic as soon as possible if you think they could be failing. Failing to do so may cause fires or engine damage.

Conclusion

Check your owner’s manual to ensure your spark plug wires are routed properly after learning how to test a spark plug with a multimeter. This is crucial because cross-coupling may create an energy loss, which would reduce performance.

The exhaust manifold, among other hot engine parts, must not come in direct contact with the spark plug wires. Long-term contact with hot engine components can lead to cracks in the insulating layer of spark plug wires.

FAQs

Reference:

• https://mrfixitca.com/test-spark-plug-with-multimeter/