How to make a simple spark plug tester

To quickly identify faulty spark plugs, you can make a device that is very simple and inexpensive to manufacture. With its help, used and defective spark plugs are calculated, which do not produce a spark and must be replaced.

Materials:

• Battery-powered electric lighter for a gas stove, can be purchased on Ali - ;
  
• large and small alligator clip;
  
• 2 M4 screws with nuts;
  
• 2 AA batteries for the lighter;
  
• a piece of stranded wire.

Assembling a spark plug tester

The device is made on the basis of any kitchen electric lighter. When purchasing it, you may mistakenly take a gas lighter. You need one that does not burn, but only generates a spark for ignition and is powered by batteries.
The lighter body is disassembled. You need to remove the metal rod coming out of it; it will no longer be needed. The wires connected to it are disconnected.

There are 2 holes made in the upper front half of the body. A large clamp is screwed through them onto the screws. It must be positioned in the same way that the removed rod was secured.

A wire from a lighter coil is connected to the crocodile.It will also require drilling or burning a thin hole in the housing.
The second wire needs to be brought out from the side. For this, a separate hole is drilled. To make it wear out less, it should be protected from fracture with heat shrink. A small clip is attached to the end of the wire. Most likely, the length of the existing wiring will not be enough, then before installing the heat shrink and clamp, you will have to extend it with a small section of 15 cm.


The device body is assembled and 2 batteries are installed in it. For aesthetics, you can cut the insulator removed from the large clamp lengthwise. The resulting segment is glued to the bare crocodile handle, screwed to the body.

To test a candle, it is clamped in a large crocodile on the threaded part. A small clip is placed on the contact tip. After pressing the button, the high-voltage converter delivers a discharge to the spark plug. If it is working, then a striking spark should appear in its gap between the side and central electrodes. A spark plug that is not working will not have a spark.

Result

When testing with this device, it will be possible to reject only those spark plugs that are damaged, punctured and are not capable of generating a spark. At the same time, some of the spark plugs tested on the tester will still not be able to work in the engine under high pressure conditions. But using the device will make it possible to weed out guaranteed worn-out spark plugs, which is very useful.

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