How To Check The Spark Plugs For Good Condition? Detailed Instructions.

Any gasoline vehicle is equipped with an ignition system. Its essential attribute is candles. Sometimes they fail, and the car behaves differently. In today’s article, we will look at how to check the spark plugs yourself on the injector.

Main symptoms.

Determine the failure of these elements can be on the nature of the car. The main features are difficult ignition, unstable engine operation, the floating engine idle speed. One of the symptoms of a malfunction is increased fuel consumption. It does not burn in the cylinder, as there is no spark. At the same time, the power of the car drops, as it works on three (if we consider modern passenger cars) cylinders. A difficult launch is also the cause of broken candles. The spark may disappear or be completely absent. As a result, the crankshaft rotates, but the ignition power in the remaining cylinders is not enough for normal operation. And it occurs even on a warm engine. Sometimes the absence of a spark in one of the cylinders provokes catalyst breakdown. The mixture that was prepared and fed into the combustion chamber does not ignite and enters the catalyst, where its elements are oxidized.

Bad start “on the cold”.

It is due to the “wet” candles. Condensate may accumulate on the electrode. Excess water can reduce breakdown voltage in the electrode gap. Voltage goes through the wet ceramic case.

High voltage wires.

Sometimes the problem is in them. They can also fail. It is effortless to check their condition. it is enough to start the engine in the dark and open the hood. Sparks should not run over high-voltage wires.

Spark check.

First, you need to remove the high-voltage wires. Do it very carefully. sometimes they stick to the contacts. Do not force the wire with force. so you will tear off its insides, which will cause breakdowns. Next, you need a hex key candle. Depending on the brand of car, it can be of different diameter. When buying such a key, be sure to tell the seller the brand and model of your car, as well as the volume of the power unit. Without this tool to unscrew the candles is simply impossible. Pulling the element out, start carefully clean it from carbon. In general, it should not be on the surface. But before you check the spark plugs yourself, we clean them of all the accumulated dirt. The first symptom of a malfunction is a large gap between the electrodes. To determine it, you need a special measuring probe. The same measure the gaps in the valves on carburetor cars. You can buy such a probe on any car market.

Diagnostics without devices.

How to check the spark plugs yourself in the absence of the necessary testers? Make it a force for everyone. There is a proven way. But you need an assistant. To do this, unscrew the candle and put on it back high-voltage wire. The assistant turns the starter. At this time, one part of the candle is directed to the mass. we lean against any metal part of the engine. It is important that there is no paint on it. Otherwise, contact will not occur. The spark must be blue.

Is it possible to clean?

If there is a fixed deposit on the electrode and the base, this is a sign of engine failure. If you clean the candle and put it back, the soot will resume again. The colour of the deposits can be indicative of many things. It is the wrong mixture, the presence of oil in the combustion chamber, etc. By the way, the lubricant enters the cylinder due to the presence of scoring or worn oil scraper ring. Pay attention to this.


So, we figured out how to check the spark plugs yourself with and without instruments. As you can see, no stand is needed for this. In conclusion, I would like to note the following. Proper operation of candles is the key to excellent engine performance. Any violation in the supply of spark. and the engine starts making amplified vibrations. Riding with such a malfunction is not recommended. Candles are inexpensive, and the damage that a “lame” engine can cause is measured in hundreds of dollars. Experienced motorists carry a set of candles in the trunk to replace them in time in the event of a malfunction.