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Why To Change Spark Plugs?

Some people says it there was a problem with the spark plugs the misfire could be felt while you are driving the car.

Short answer: Because worn spark plugs can damage the ignition transformer.

My case with the ignition

After the car turned 23 years old with 310,000 kilometers, during a longer trip I noticed that the check engine light came on. I took my OBD adapter, an ELM 327 and the Car Scanner Android app, with which I saw that the problem was a misfire in cylinder 1.

According to the char mechanic

I took it to the Feldinger service center and the mechanic suspected the ignition transformer. We tested what happens if we change the ignition transformers of the first two cylinders. The error also occurred, but in this case for cylinders 1, 2, and 3. To this, the mechanic said that it is not certain that the problem is with the ignition, maybe there is too much coke in the engine. He recommended the use of fuel additives. We filled approx. 3 dl to the tank approx. for 10 liters of gasoline, and then the mechanic said that the gasoline in the tank, now with the additive, must be consumed by the engine. That's what I did, I drove the car approx. 120 kilometers, then I deleted the error message. After refilling the tank and driving about 5-10 kilometers, the error occurred again. The mechanic said that he did not know what could be the cause of the error and that he could not find out. His tips were that either the ignition transformer or the injector or the engine control electronics were the cause of the failure, but he also mentioned that the 7th gen Honda Civic does not usually have engine control electronics failure. He recommended car mechanic József Gergely, who can deal with the problem in more detail. I took the car to him, and after he encountered the phenomenon of the error, he also suspected the spark plug and the ignition transformer. And he also said that if none of these, then it can be a mechanical fault ie. a valve does not open. Made a compression measurement with the following result.



He said that a result above 80% is acceptable. Since with the exception of one cylinder we got a result within the limit and the lowest one was 79%, so overall the compression is fine and this cannot be the cause of the error. After the ignition transformers were replaced, the ignition pattern changed completely.




The problem was caused by the fact that the spark plugs were not replaced in time and this damaged the ignition transformers. The mechanic recommended changing the spark plugs every 30,000 kilometers.

Recommendation by Honda factory

According to the factory recommendation, the spark plugs are needed to be changed after every 40,000 kilometers.