In this article, we will talk about car shaking, long start time, sometimes it takes several times to start car, fuel consumption is clearly increased, response to pressing accelerator pedal is slow, car accelerates slowly, and occasionally there is a phenomenon of stalling at idle, etc. .d. All these malfunctions are connected with "it" and ignition system of the car engine. This "it" is specifically "spark plug".
Of course, professional auto repairers will say that they cannot be generalized, and there are many other factors that can cause above failure phenomena, such as an abnormal fuel supply system, malfunctions in on-board computer control circuit. etc., which will lead to aforementioned failure phenomena. In this article, we will talk about effect of most common "spark plug".
What are symptoms of an engine with a broken spark plug: Difficulty starting Too much carbon deposits on spark plug or too much accumulated sediment, gap between spark plugs widens, and ignition energy is insufficient, which makes it difficult to start car. If power is low, carbon layer on spark plug is too thick, resistance of shunt is reduced, and spark generated by electrode deteriorates, resulting in unstable engine operation and reduced power.
For petrol engines, spark plug is a very important part (a diesel engine doesn't need spark plugs, so it won't be discussed here). See picture below:
As we all know, when you press gas knob on a gas stove at home, you will hear a “click-boom-boom” sound. If gas regulator knob is turned again at this time, gas is atomized and mixed with surrounding air, forming a mixture that can be burned. When mixture meets "sparks", gas stove ignites. Lighters we often use in daily life, when you press ignition button, there will also be "sparks" and at same time press gas valve, sparks will meet with outflowing butane gas (hydrocarbons) and surrounding air to form a mixture of combustible mixture, mixture ignites.
The sole purpose of a spark plug is to ignite gasoline-air mixture in an engine cylinder. After combustion of mixture occurs, a series of reactions will be created to form power output of engine.
The combustible gas (petrol-air mixture) in combustion chamber of a car engine is also ignited by a "spark". What produces this "spark" is a "spark plug, also known as a spark plug". Spark plugs are widely used in gasoline powered power equipment such as car engines, motorcycle engines, lawn mowers, tree pruning chain saws, yacht and motorboat engines, etc. The estimated number of spark plugs consumed annually in world is in billions. .
Since spark plug is so common in our daily lives, what does it look like? How it works?
What failure phenomenon can be caused by a faulty spark plug?
As we mentioned earlier, gasoline engines must use spark plugs to keep engine running. Then, if spark plug performance is poor or damaged, engine tries to ignite mixture in cylinder, but fails to ignite. First of all, first sign of this kind of malfunction, i.e. non-ignition of mixture, is that engine failure warning light on instrument panel will light or flash. This warning light will come on many times until spark plugs are completely worn out, or stay on until vehicle is taken to a service center. It is very important for car owners to know that check engine light will be on or flashing for many reasons. In this case, it is necessary to use a computer diagnostic tool to diagnose car in order to further determine specific problem. cause of engine warning light.
According to on-board computer control system fault information records displayed by computer diagnostic tool, for example, on-board computer control system records fault codes: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0309, P0310, P0312, etc. We can know that all these trouble codes mean that mixture in cylinder has not ignited and combustion is not working. This is commonly referred to as a missing cylinder or a misfire, commonly known as "lame". At this time, driver may notice changes in vehicle, such as: vehicle shaking, unstable idling speed, fuel gauge needle drops sharply, or digital fuel consumption shows that fuel consumption is increasing, vehicle start time is increasing; power drops, etc. Seriously, engine will stall or won't start, engine won't start or stall after starting.
Is it possible to continue driving car if spark plugs are faulty?
If vehicle exhibits above symptoms, exhaust pipe of 3-way catalytic converter will produce an excess amount of unburned gasoline/air mixture. The three-way catalytic converter is an engine exhaust cleaner. Unburned mixed gas will cause actual temperature of three-way catalyst to exceed calculated normal operating temperature, and this high temperature will cause permanent damage to three-way catalyst. In accordance with provisions of Environmental Protection Law, three-way catalytic converter must operate normally in order to meet requirements of use of vehicle. Therefore, it is necessary to replace a new three-way catalytic converter (very expensive).oh accessory). This will greatly increase cost of maintenance.
Do I need to change spark plug on time?
We know from block diagram of previous spark plug that it cannot be taken apart. The spark plug is located in combustion chamber and is exposed to high pressure, flame, high temperature, gasoline, soot, etc. Under normal conditions, spark plugs that have been driven over 100,000 kilometers are bound to be damaged. If, under relatively poor engine operating conditions, spark plug fails for tens of thousands of kilometers. Especially for spark plugs of modern direct injection engines, some manufacturers stipulate need to replace spark plugs after a vehicle has driven 20,000 kilometers.
According to structure of spark plug, for example, most commonly used is ordinary spark plug made of nickel alloy (nickel) electrode, electrode material of best spark plug is made of platinum (platinum) metal electrode. , and more advanced spark plug is metallic iridium (iridium), which is used to make electrodes, because metallic iridium is most oxidation and corrosion resistant metal material currently known, which can greatly extend life of spark plug. But we still have to replace spark plugs regularly according to manufacturer's recommended mileage.
How do I diagnose a spark plug problem?
With above mentioned vehicle failure phenomenon, first thing to do is to use a professional computer to diagnose vehicle. After computer diagnostics, technician can understand why engine is not working properly. If technician sees that information read by diagnostic computer is related to spark plug, technician will additionally check connection of spark plug connector to ignition coil, or connection of high voltage ignition line of old ignition system is normal, etc. If connectors and connections of high voltage wires are normal, technician removes spark plug from cylinder head for further inspection. If electrode gap of spark plug is too small, or it is contaminated with soot, or electrode is highly ablated, or electrode gap is too large, etc., such a spark plug must be replaced.
Of course, if spark plug is in good condition, technician will use a spark tester to determine intensity of spark to check if spark plugs can produce strong sparks.
Technician measuring spark plug gap
If it is outside specified range, spark plug should be replaced
Comparison of normal and faulty spark plugs
Compared to a normal working spark plug, appearance of spark plug can be very different. The spark plug head in picture above, center electrode and ground electrode are covered with a thick layer of soot. Such a spark plug cannot normally ignite gas mixture inside cylinder and must be replaced, as well as finding out reason for formation, why gas mixture is thick, and proper repair.
Common type of spark plug failure
There are many forms of spark plug failure. If combustion chamber temperature is above normal, deflagration will occur, which will melt electrode and crack ceramic insulator as shown in figure above. Due to lack of space, I will not list them one by one.
What should car owners look for when there is a problem with a spark plug?
Replacing spark plugs can be inexpensive or expensive. If, as a preventative measure, it is regularly replaced according to manufacturer's instructions, maintenance and diagnostic fees can be saved, since there is no need for troubleshooting. Other factors that affect cost of a replacement are make and model of vehicle, choice of repair shop, and brand and number of spark plugs. Since replacement of some models is very laborious, and price difference of different types of spark plugs, running costs of replacing spark plugs are also high and low. The number of spark plugs required for most vehicles is between 3 and 16. Some special models have 2 spark plugs per cylinder, and 12-cylinder engines require 24 spark plugs. Different workshops have different charging standards, so charge for changing spark plugs will be different.