How to test spark plugs with a multimeter
Content
Spark plugs work under extreme conditions of high pressure, which is created in the combustion chambers before the fuel ignites. This pressure causes the breakdown of the insulation of the auto component: the spark either disappears completely, or appears only once.
Checking the resistance of a spark plug with a multimeter is a simple job that you can do yourself. However, the stable operation of the engine nevertheless depends on such a “trifle” in terms of physical costs and time of the procedure.
Is it possible to check the spark plug with a multimeter
The miniature do represents a key component of the ignition system of a car running on gasoline or gaseous fuels.
When one element fails, the motor does not stall, but on the remaining cylinders it troit and vibrates. Without waiting for irreversible destruction processes (detonation in the chamber where unburned gasoline accumulates), drivers begin to “look for” a spark.
There are many ways, but checking spark plugs with a multimeter is perhaps the most affordable. A simple electrical device for determining various current parameters never shows a spark, as an unequivocal sign of the candle's performance. But according to the measured indicators, we can conclude: the part is working or unusable.
Breakdown test
Spark plugs work under extreme conditions of high pressure, which is created in the combustion chambers before the fuel ignites. This pressure causes the breakdown of the insulation of the auto component: the spark either disappears completely, or appears only once.
Usually a defect is visible to the naked eye: a crack, a chip, a black track on a corrugated base. But sometimes the candle looks intact, and then they resort to a multimeter.
How to check spark plugs
Do it simply: throw one wire on the central electrode, the second - on the "mass" (thread). If you hear a beep, throw away the consumable.
Resistance test
Before checking the spark plugs with a multimeter, test the device itself: short the red and black probes together. If “zero” is displayed on the screen, you can check the voltage of the sparking devices.
Prepare the parts: dismantle, remove carbon deposits with sandpaper, a metal brush, or soak overnight in a special auto chemical agent. The brush is preferable, as it does not “eat up” the thickness of the central electrode.
Next steps:
- Plug the black cable into the jack labeled "Com" on the tester, the red one into the jack labeled "Ω".
- Turn the knob to set the regulator to 20 kOhm.
- Place the wires on opposite ends of the center electrode.
In the Russian or English version, the symbols indicate a part with a resistor, that is, with zero resistance (for example, model A17DV).
How to check without removing the spark plugs
If a multimeter is not at hand, rely on your own hearing. Drive the car first, give the engine a significant load, then diagnose:
- Drive the car into the garage, where it is quiet enough.
- Without turning off the power unit, remove the armored wire from one of the candles.
- Listen to the hum of the engine: if the sound has changed, then the part is in order.
Test all the auto components of the ignition system one by one.
How to test a spark plug with an ESR tester
The ESR tester is designed to work with electronic equipment. The device is equipped with a screen that displays the parameters of various electronic components, a power button and a ZIF-panel with fasteners for placing the diagnosed elements.
Capacitors, resistors, stabilizers, and other components of electronic equipment are placed on the contact pad to determine the equivalent series resistance. Car spark plugs are not included in the list of radio components.
