What are the reasons for the unstable idle speed of the engine?

There are several possibilities for the engine to idle unstable and extinguish the car after the engine is warmed up: 1. There is vacuum leakage in the air intake system; 2. The fuel pressure is too low. 3. The ignition system is faulty.

4. The engine electronic control system is faulty. 5. The engine exhaust gas recirculation system is faulty. 6. The fuel injector is faulty.

Since the engine is the heart of the car, this has a great impact on the use of the car, and it is recommended to overhaul it immediately.

Causes of unstable car idling.

1. Air leakage from the intake manifold.

When the air that should not be entered, gasoline vapor, and combustion exhaust gas enter the intake manifold, the mixture is too thick or too thin, causing the car to idle unsteadily.

2. Too much carbon deposition on the throttle.

Excessive carbon deposition in the throttle valve and surrounding air intakes, and changes in the cross-sectional area of the air channel, make it impossible for the control unit to accurately control the amount of air intake at idle, which will also lead to too thick or too thin mixture, resulting in unstable idling of the car.

3. Failure of the actuator of the air intake system.

There are many actuators in the engine intake system, such as throttle motors, idle stepper motors, duty cycle solenoid valves, air flow meters, intake pressure sensors, etc., which cause the car to idle unstable.

4. Fuel system failure.

Faults such as clogged injectors, clogged fuel filters, clogged fuel pump filters, faulty fuel pressure regulators, and clogged return pipes can all lead to incorrect fuel injection, resulting in over-concentrated or over-thin mixtures, resulting in unstable car idling.

5. Ignition system failure.

Faults such as ignition module failure, incorrect spark plug clearance, spark plug electrode ablation or damage, and excessive resistance of the high-voltage line lead to a decrease in ignition spark energy or misfire, resulting in unstable idling of the car.

Cause of failure:

1. There is air leakage in the air intake system.

2. The fuel pressure is too low.

3. The air filter is blocked.

4. Poor atomization, oil leakage or blockage of the injector.

5. Improper adjustment of idle speed.

6. Poor working of idle control valve or bypass air valve.

7. The spark plug works poorly.

8. The air flow meter is faulty.

9. The compression pressure of the cylinder is too low and uneven.

Fault diagnosis and troubleshooting

1. Conduct fault self-diagnosis first and check whether there is a fault**. If there is, find the fault location by fault **.

2. Check whether the air intake pipe joints, vacuum hoses, exhaust gas recirculation system and fuel vapor ** system of the intake system are leaking.

3. Check whether the idle control valve is working normally. Unplug the wiring plug of the idle control valve, if there is no change in the engine speed, it means that the idle control valve or control circuit is faulty and should be overhauled or replaced.

4. When idling, short circuit the high-voltage lines of each cylinder one by one, and check whether the drop value of the engine speed is equal. If the engine speed of a cylinder is basically unchanged when the high-voltage line is short-circuited, it means that the cylinder is working poorly or not working, and the spark plug or injector or control circuit of the cylinder should be checked to see whether the cylinder is normal and whether the cylinder pressure is too low.

5. Listen carefully to the working sound of each cylinder injector at idle. If there is a difference in the working sound of each cylinder injector, it means that the amount of fuel injected by each cylinder is not equal, and it should be disassembled or replaced.

6. Check the high-pressure sparks of each cylinder. If the spark of a cylinder is too weak or the fire is broken, the fire distributor head, distributor cover, high-voltage distribution line, igniter, engine speed sensor and its connection, plug, etc. should be detected. 7. Disassemble and inspect the spark plugs of each cylinder and each cylinder, check whether the electrodes are ablated or even carbon deposited, and whether the spark plug electrode gap is normal.

8. Check the fuel pressure. The fuel pressure at idle should be around 250kpa. If the fuel pressure is low, check the oil pressure regulator, electric gasoline pump, gasoline filter and the inlet filter and connecting lines of the electric gasoline pump.

9. Adjust the engine idle speed. Check whether the air flow meter is stuck and check the cylinder compression pressure. If the pressure is lower, the engine should be dismantled and inspected.

And; Is the mixture too thin? Throttle? Fuel injectors?

Air-fuel ratio? Oxygen sensor? Air intake sensor?

Dirty fuel? High engine temperature? Air resistance?

Improper adjustment? Gasoline pumps? Triple filter?

Circuit? and many other factors.

The reasons are:1There is a leak in the air intake system 2. The fuel pressure is too small 3. The air filter is clogged 4. The injector is poorly atomized, leaking or clogged 5. The idle speed is not properly adjusted 6. The idle control valve or Pangtong air valve is working poorly 7. The spark plug is working poorly.

There are several possible reasons for this: The idle speed is too low. The engine sometimes idles as low as 500r min and then stalls.

2) The throttle is opened too much (3) The amount of fuel injected is too large. (4) The air intake is too large. (5) The mixture may be too thin.

Excessive carbon deposition in the intake branch pipe causes a mixture gas loss ratio, and FAW-Volkswagen's cars are most prone to a similar situation.

The causes of engine failure are: firstly, the lubricating oil consumption is abnormal, which is usually caused by three reasons: first, the sealing of the engine piston, resulting in too much gap between the piston and the cylinder wall, and the situation of burning engine oil; The degree of wear of engine parts is too large, the gap between parts is large, and there is abnormal lubricating oil consumption; Third, the quality of lubricating oil is not up to standard, resulting in abnormal oil consumption.

For the maintenance of lubricating oil, we should first check the quality and quantity of lubricating oil, and replace it with new lubricating oil if necessary to avoid engine failure due to oil quality problems. After ruling out the quality of the oil, the parts should be checked. An abnormal engine can be due to excessive wear between parts, too much clearance between parts, or too high oil pressure, resulting in oil burning.

In addition, the main causes of oil leakage are the aging of the gasket and the stuck valves.

Hello According to your description, insufficient power generation at idle speed will cause the alternator nonlinear signal to be distorted, and the resulting electromagnetic interference will affect the injector, causing the engine to shake slightly at idle and return to normal after starting.

The common faults of unstable engine idle are:1Air leakage 2 throttle carbon deposition more than 3

Gasoline Oil Problem 4The spark plug gap is too large and the ignition is poor 5Ignition coil high voltage ignition weak 6

Excessive carbon deposits in the engine 7The cylinder pressure is too low 8The air filter is too dirty 9

Injector clogging 10The idle speed is too low.

1. The combustion of the mixture is insufficient, too concentrated or too thin.

2. The carbon deposit of the throttle valve and the surrounding air intake is excessive, and the suitable air intake volume is unstable 3. The spark plug is not working properly.

Hope it helps.

It mainly introduces the engine idle motor throttle is too dirty, and the idle speed is unstable.

The common faults of unstable engine idle are:1Leakage.

2. The throttle valve has more carbon deposits.

3.Gasoline oil problems.

4.The spark plug gap is too large.

Poor ignition. 5.The ignition coil has weak ignition at high voltage.

6.The engine has too much carbon deposit.

7.The cylinder pressure is too low.

8.The air filter is too dirty.

9.The injector is clogged.

10.The idle speed is too low.

<> "The fault phenomenon of unstable engine idle speed or easy to stall is that the engine starts normally, but whether it is cold or hot, the idle speed is unstable, and the idle speed is too low, and it is easy to stall.

Cause of failure:

1.Leakage of air in the air intake system or vacuum system; 2.clogged air filter; 3.Improper idle adjustment, poor working of the idle control valve or additional air valve. 4.The air flow meter is faulty; Exhaust gas recirculation control) valve is stuck normally open and cannot be closed.

6.The oil pressure is too low; 7.Poor atomization of the injector, oil leakage or blockage; 8.Poor spark plugs; 9.High voltage line leakage or open circuit: 10ignition timing is inaccurate; 11.The cylinder compression pressure is too low.

Troubleshooting

1.Perform fault self-diagnosis and check whether there are fault codes. 2.

Check the intake system tube plugs, vacuum hoses, EGR system, and fuel vapor** system for air leaks. 3.Check that the idle control valve is working properly.

4.When idling, unplug the high-voltage wires of each cylinder one by one, and check whether the decrease in engine speed is equal. 5.

Check for high-pressure sparks. If the spark smile is too weak, the ignition system should be checked.

6.Check the fuel pressure. 7.

Adjust the engine idle speed according to the prescribed procedure. 8.Check the air flow meter.

9.Listen carefully to the sound of each cylinder's injectors at idle. If the working sound of each cylinder injector is uneven, it means that the fuel injection of each cylinder injector is uneven, and the injector should be disassembled, cleaned or replaced.

10.Check the cylinder compression pressure, if the pressure is lower, the engine should be dismantled.

This may be due to a malfunction in the air intake systemIt could be due to a malfunction in the ignition system, or it could be a malfunction in the fuel supply system. After such a situation, it is recommended to go to the 4S shop or a professional repair organization to read the fault code, which can help the technician quickly find the cause of the fault and the location of the fault problem.

The ignition system of the engine functions a role.

The key components of the ignition system for igniting combustible mixtures include spark plugs and ignition coils.

Spark plugs require regular replacement of wear parts, and the performance of the spark plug may also deteriorate over time. There are electrodes on the spark plugs, and the electrodes can release electric sparks. As time increases, the electrode gap of the spark plug may also increase.

Everything else is not important, clean the throttle idle motor, after cleaning, the computer recognition and learning once or twice, it's OK, it's best to ultrasonic clean the fuel injector, and the other Langdi run one or two hundred thousand don't care!

Most of the cold start jitter is caused by poor fuel combustion, the fuel tank has more gum moisture, and the cold start is not brought to the combustion chamber and then mixed in the fuel tank is driven into the combustion chamber, and the jitter caused by poor combustion.

There are several causes of engine shake;

1. The engine has serious carbon deposits, and the most common car with serious shake is that the fuel injector throttle valve is too dirty or too much carbon;

2. Ignition system problems, check the working conditions of spark plugs, high-voltage wires and ignition coils;

3. If the oil pressure is unstable, if the pressure of the pump is abnormal or the error and poor work of the inlet pressure sensor will cause the body to shake;

4. Aging of engine parts; Excessive carbon deposits in engine emissions absorb carbon from the gasoline of the cold-start injector, which leads to a dilute cold-start mixture and difficulty starting.

Specific solutions to idle jitter:

1. The engine has serious carbon deposits. The most common cause of idle judder is excessive carbon build-up on the throttle or injector. When there is too much carbon deposit inside the engine, the gasoline sprayed by the fuel injector during cold start will be absorbed by the carbon deposit, resulting in a mixture that is too thin and making it difficult to start.

After landing, the gasoline adsorbed on the carbon deposits will be sucked into the cylinder by the engine and burned, which will thicken the mixture. The mixture is sometimes dilute and sometimes thick, which will cause idle jitter after cold start. The lower the temperature, the greater the amount of oil required for cold starts, and the more the presence of carbon deposits affects cold starts.

The solution is to clean the carbon deposits at the throttle and injector.

2. Poor ignition system and poor ignition of spark plugs will also lead to engine idling and shaking. If there is a problem, check if the ignition system is faulty and if there is too much carbon deposited in the spark plug.

3. The oil pressure is unstable. If you have cleaned the engine carbon deposits, cleaned the throttle valve or replaced the spark plug, and there is still the problem of body shaking when idling, it is recommended to go to the 4S shop to check whether the fuel supply pressure and intake pressure sensor are normal. If the oil pump is not properly supplied or the intake pressure sensor is incorrect, it will also cause the body to shake at idle.

Solution; The best way is to clean the oil circuit, clean it regularly, there is no specific experience in the research and development parameters of the clean engine from the new car, coupled with the continuous improvement of emission standards, can not adapt to the change of fuel, all manufacturers of the engine are unable to solve this jitter problem in the short term, plus the fuel quality is not very good or the initial fuel of the new car factory is stored for too long, resulting in a rapid increase in the colloidal composition of the oil circuit, which will continue to pollute the fresh fuel and cause no good fuel to participate in combustion in the later stage. The occurrence of excessive carbon deposits is especially common for China VI vehicles. We can only gradually alleviate most of the problems by maintaining clean oil circuits. The use of PNF dope fuel additives can solve the problems caused by carbon deposition.

Causes of unstable engine idle speed and troubleshooting methods:

1. Excessive fouling of the throttle or inlet duct, if the maintenance and maintenance of the engine are not in place after working for a long time, excessive fouling and carbon deposition on the throttle or intake duct will cause changes in the cross-sectional area of the inlet duct;

2. This affects the calculation of the air intake volume of the ECU, resulting in unstable idling. Oil pollution and carbon deposits will also cause the idle control valve to jam and the throttle to close loosely, resulting in unstable idling.

3. Due to the failure of the air flow meter or its circuit, the intake pressure sensor or its circuit failure, the ECU receives the wrong information and issues an wrong command, which causes the engine to control the idle air intake inaccurately, so that the engine burns abnormally, which is an indirect cause of the instability of the idle speed;

4. In addition, poor contact of the plug of the engine control unit or internal failure of the computer will also cause this phenomenon.