What are the causes of engine fire? Does the first cylinder of the engine catch fire matter?

1, the spark plug is faulty, blocked or damaged;

2. There is something wrong with the cylinder pipeline;

3. There is something wrong with the ignition coil;

4. There is something wrong with the injector, and the injector data inside DME is lost due to blockage or low voltage;

5. There is something wrong with the mixed gas;

6. There is something wrong with the cylinder pressure;

What is engine cylinder fire and how to repair it?

Harm of engine cylinder fire

Engine cylinder fire will have serious consequences for the engine. After the engine is turned off, high-concentration hydrocarbons will enter the exhaust system, resulting in excessive exhaust emissions. High concentration of hydrocarbons will also increase the temperature of the three-way catalyst, which will seriously damage the three-way catalyst.

1, the most serious thing is to cause three-way catalytic damage;

2. The second serious problem is that the emission of harmful substances in waste gas will increase by more than 1.5 times;

3. The third and lightest fire will lead to the failure of automobile exhaust emission;

How to monitor engine misfire

In order to prevent the exhaust emission from exceeding the standard and the thermal damage of the three-way catalyst, the engine control unit uses the crankshaft position sensor to monitor the speed deviation when the engine rotates to determine the misfire, and uses the camshaft position sensor to identify the misfiring cylinder. When the misfire rate of the engine exceeds the threshold and may lead to excessive emissions, the engine control unit starts to calculate the number of misfires of the engine.

How to repair engine fire

In the process of eliminating engine misfire, we need to pay special attention to three points, namely cylinder pressure, ignition and fuel injection.

1, measure engine cylinder pressure:

It is easy to detect with the cylinder pressure gauge, so I won't go into details here, but it is difficult to detect the hardness change of the valve spring and the wear degree of the camshaft when measuring the cylinder pressure, and it is also necessary to consider whether the intake air is enough (air leakage or valve carbon deposition).

What is engine cylinder fire and how to repair it?

2, check the engine ignition:

For the maintenance of engine fire, it is sometimes impossible to find the problem only by reading the engine data stream, and further judgment is needed with the help of oscilloscope. The factors to be considered during ignition include ignition timing, whether the spark plug works normally, whether the resistance of high-voltage line is within the standard value range, whether the ignition coil works normally (whether the power line and signal line are virtually connected), and whether the engine control unit works normally (including the signal provided by CAN data). It is recommended to use instruments for testing as much as possible, such as:

A, using oscilloscope to check the synchronization of camshaft sensor and crankshaft position sensor can analyze the existence of misfire and the accuracy of ignition timing and valve timing;

B, check the working condition and ignition time of the ignition coil with an oscilloscope, and analyze the quality of the spark plug;

C, using an oscilloscope to check the connection of data lines between control units;

D, using a megger to detect the resistance of the spark plug;

E, use a multimeter to detect the resistance of the high-voltage line;

What is engine cylinder fire and how to repair it?

3, check the nozzle:

One is to check the fuel injection pulse width, ignition time and the working state of oxygen sensor through data flow.

Second, use oscilloscope to check the synchronization of throttle position sensor TPS and fuel injector, and check the synchronization of TPS and oxygen sensor.

Then check the synchronization between the fuel injector and the oxygen sensor (spray cleaning agent into the air inlet when idling).

Check the change of fuel injector and oxygen sensor)

Finally, check the single waveform of the injector, and analyze the quality of the injector and the length of injection time (compared with the standard waveform)

Finally, the gasoline grade, knock sensor and three-way catalyst used should be considered.

Many maintenance stations like to check the fire by replacing parts. Although it is not recommended, sometimes it can quickly troubleshoot.

What is engine cylinder fire and how to repair it?

Eliminating cylinder misfire by replacing parts

If an alternative method is used for inspection, the following alternative methods are recommended:

For example, if 1 cylinder is on fire, we can use 1 cylinder to replace the cylinder pipeline of cylinder 2, use it to replace the injector of cylinder 3, and use cylinder 4 to replace the spark plug. After this replacement, we will try again until the fault occurs again. If the fault becomes misfire in cylinder 2, it is a cylinder pipeline problem; If there is a fire in cylinder 3, it is an injector problem, and so on. If the fault does not transfer, please consider the mechanical fault or other component fault.

In fact, after reading the above, do you think that the troubleshooting of engine fire is not complicated? Usually, the ignition system has many faults. Checking the spark plug and ignition coil can generally solve 8% or 90% of the fire problem.