How to test Spark plug with Multimeter

How to test spark plug with multimeter. Suppose you’re getting ready to go on a trip, but the engine won’t start after you’ve loaded your stuff into your car. It’s possible that this is due to malfunctioning spark plugs.

How to test spark plug with Multimeter

As a result, it’s critical to make sure your engine’s spark plugs are in good working order. You may achieve this by testing them regularly. A multimeter is the most effective testing tool.

Why do we need a spark plug?

A spark plug is an electric spark-igniting device installed in the head of a cylinder in a combustion engine. It delivers heat to the engine’s cooling system by eliminating unneeded thermal energy from the combustion chamber.

A spark plug’s primary duties are to ignite the fuel-air combination and to monitor electrification in the engine cylinders.

Before you start testing

It’s critical to test each wire independently for these tests. To put it another way, detach one wire, test it, then reconnect it before moving on to the next wire. Ensure the cable is not too adjacent to other devices or any hot, such as the exhaust, while reconnecting it.

Arranging your tools and gear such that everything is conveniently accessible can save you time. The engine isn’t operating for the grounding test, but it is turning over.

Test spark plug with a multimeter

  • Clean each wire with a cloth and inspect it for physical damage such as cuts or scorch marks on the wires or boots attraction between the boot, spark plug, and coil.
  • Check for electrical arcs around the cables after starting the car.•
  • disconnect the fuse for the fuel pump in fuel-injected autos.
  • Assess the spring clips that hold the wires inside the distributor cap if there is no visible damage.
  • You must separate the pipework from the fuel pump on carbureted engines.
  • Operate the engine once all of the gasoline in the system has been burned out.
  • You should remove the spark plug. Unscrew the installation bolt and extract the coil from the plug-on automobiles with coil packs.
  • Pull the plug wire loose from the spark plug on an older engine. This is considerably easier for you and the wire if you use spark plug pliers.
  • Remove the cylinder head’s spark plug. Set the ohms setting on the multimeter. Measure the resistance between the probes.
  • Check the resistance of each spark plug wire using a digital or analog multimeter to see if it meets the manufacturer’s specifications
  • To guarantee that you obtain an accurate reading, ensure there is no resistance in the probes. Connect one lead to the plug’s end terminal and the other to the middle electrode.
  • Ensure to test and reconnect each wire to the proper scale and measure the wire by inserting probes on either end of the wire lead, ensuring they meet the electrical components. If the measurement is within the manufacturer’s specifications, you can restore the wire to the automobile before moving on to the next wire.


Now that you know how to test spark plug with a multimeter check your owner’s handbook to ensure your spark plug wires are correctly routed. This is critical because cross-coupling might result in an energy loss, lowering performance.

The spark plug wires must be routed to not directly touch with any hot engine components, such as the exhaust manifold. Contacting heated engine parts for an extended time may cause fractures in the insulating layer of spark plug wires.

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