The detection steps of the engine jitter fault
1. After starting the engine, check whether the engine fault warning light is off
2. If the warning light does not go out, check the cause and location of the fault according to the fault code; if the warning light goes out, determine the rapid matching setting
3. Check whether the cylinder is missing, whether the cylinder line is correct, and whether the connector connection is reliable
4. Check whether the idle speed actuator is normal.
5. According to the signal voltage of the oxygen sensor, judge whether the idling mixture is too rich or too lean. If it is too rich, check whether the system oil pressure and each sensor are normal, check whether the activated carbon canister is working normally, check whether the fuel system actuator is working normally, and check whether the ignition system is working normally. too thin, check
Check whether the ignition system is normal, check whether the oil pressure of the system is normal, check whether the vacuum tube is leaking, and check whether each sensor is checking whether the fuel injector, EGR valve, and cylinder pressure are normal.
6. Check whether the engine bracket and buffer rubber pad are damaged.
Engine idling jitter fault diagnosis and elimination process Analyze various causes of the electronic control system idling instability fault, and do the following inspections
1. Carry out the cylinder break test
When the 1-cylinder high-voltage line is unplugged, the engine speed increases instead; when the 4-cylinder high-voltage line is unplugged, the engine has no obvious response; when the 2- and 3-cylinder high-voltage lines are unplugged, the speed decreases. After removing 4 spark plugs, it was found that the center electrodes of the 1st and 4th cylinder spark plugs were ablated. After replacing all the spark plugs, the engine was started, and the idle speed improved slightly.
2. Check the intake system
If no air leakage is found, the idle speed valve can be removed for inspection, and the idle speed channel and valve can be cleaned and installed with cleaning agent, and the test drive is performed. If the problem is still not solved at this time, and the engine accelerates normally, and the fault code is not read out by the instrument, it is considered that it is not possible that it is caused by a circuit or ECU fault.
Yes, there should be no problem with the fuel system.
3. Carefully analyze the cause of the failure again
It is believed to be caused by excess intake air in the intake system. It can be considered whether there is a problem with the exhaust gas recirculation valve. Unplug the vacuum tube on the waste recirculation valve, the engine does not change, and further remove the waste recirculation valve, it can be seen that there is fouling in the waste recirculation valve, and the valve is not closed tightly, causing waste
Air has been entering the intake system to participate in combustion, resulting in unstable engine idle speed. Replaced the new parts and tested the car, everything is normal, and the fault is eliminated.
