The idling speed is a bit abrupt

Is it normal to have a sudden engine sound when accelerating, and occasionally to hear it when idling?

There are a lot of systems that cause this phenomenon and you go for overhaul.

When the engine is idling, it vibrates and makes a "sudden" sound, and the sound disappears when the rev is increased, and the operation is smooth. The main reasons are as follows, individual valves are poorly sealed or burned. Individual valves are poorly sealed and leak severely.

There is carbon deposits between the seat and the valve. Individual valve clearances are too small and there are no clearances. The exception to this is the detachment of the vacuum tube of a car with a boost.

The sudden rhythmic sound of the engine at various speeds makes it difficult to accelerate due to severe engine shaking. The mixture is too thick.

The ignition system is turned off, the distributor cam is seriously worn, some of the distributor holes are dirty, some of the high-voltage lines are leaking, and some of the spark plugs are seriously leaking or the gap is too small. Caused by mechanical parts, part of the water jacket passes through the cylinder, and part of the intake valve enters the water. The piston ring is poorly sealed, and the lock ring locks the piston and opens the cap.

The intake valve clearance is too large, the valve spring is broken, and the lock plate falls off, and the adjustment wire falls off. The engine works well at low speeds, there is an irregular sudden noise at medium speeds, which makes the car unmoving, and the distributor circuit breaker contacts are too soft.

Contact rivets are loose, fixing brackets are loose, and valve clearance is too large or too small. Defective electrical equipment or poor wiring. The distributor shaft is loose, the ignition coil is not working well, the spark plug gap is too large or the insulation is poor, and the ignition is too late.

The valve springs are not elastic enough, and the valve clearance is too small. Excessive fouling of the throttle and air intake, and excessive carbon fouling of the throttle and surrounding air intakes. The change of the cross-sectional area of the airway makes the control unit unable to accurately control the idle air intake, resulting in the mixture being too thick or too thin and burning abnormally.

Common causes are: carbon deposits on the throttle, oil contamination, and carbon deposits at the intakes around the throttle.

Idle Air Actuator Failure Idle Air Actuator Failure Leads to Inaccurate Idle Air Control. Common causes are: throttle motor damage or hairpin, throttle valve plate carbon deposit.

The incorrect air intake control unit receives the wrong air flow sensor signal and issues the wrong command, resulting in inaccurate air intake when the engine is idling, and abnormal mixture concentration leads to abnormal combustion of the engine, which is an indirect cause of unstable idling. Common causes are: failure of the air flow meter or its circuit; inlet pressure sensor or its circuit failure; Poor wiring harness contact of the engine control unit or unilateral self-failure of the engine control.

When idling unsteadily, it is recommended to check the above parts.

It may be that there is a problem with the spark plug operation, or there is an air leak in the vacuum tube, or there is a leakage in the high-voltage line, or there is a sensor failure problem with the throttle valve, or there is a fault with the idle motor.

The friction of the engine is too large, it is likely that there is too much grease, and such a sound will occur when it rotates.

If your spark plug is faulty, it is also possible that the high-voltage line is leaking, the PCV valve is blocked, and the air intake system is leaking, so you should go to the repair shop to check it in time.

There are many reasons, you need to combine the actual situation of your car, if you want to get the best of this problem, you need to provide detailed information about the car, such as how many miles, how many years the car has, the oil used, whether there is a similar phenomenon in driving, etc.

Generally speaking, after 1 year or 20,000 kilometers of normal use, there will be a lot of carbon deposits in the entire fuel system, which will bring many disadvantages to the car, such as engine weakness, engine shaking, high fuel consumption, unstable idling, excessive exhaust gas, etc.

The causes of the in-situ idle exhaust pipe protrusion are: oil circuit blockage, poor patency, rail pressure, etc.; Abnormal electric fuel pump or fuel filter blockage due to various reasons, obstruction of transportation, etc.; Abnormal fuel injector: It can be caused by the quality failure of the injector itself, or by the blockage caused by foreign matter, poor sealing, aging of the rubber ring, etc.

Intake or idle control: Stepper motors, throttle valve bodies are dirty or leaking. Sensors such as atmospheric pressure, temperature, and throttle position are abnormal, and the data is incorrect; Too thin: a combination of gas mixtures or fuel that is too thin. Check the air intake part, oil circuit, etc.

Splitting wire: Leakage and insufficient ignition strength due to presbyopia or cracking of the splitting wire. or poor contact due to installation problems. Suggestion: Replace the original distributor wire.

Heat dissipation: it is difficult to start, and the exhaust pipe is discharged when starting, which is similar to the mixture being too thin; In the case of overheating (poor heat dissipation), the water temperature is too high. Suggestion: Check the cause of excessive temperature, troubleshoot, or replace the cylinder gasket according to the actual situation.

Ignition (distributor, ignition coil, etc.): too late: too late ignition causes the mixture to fail to burn completely, it is recommended:

Turn the shell at the distributor against the rotation direction of the distributor head at an appropriate angle to eliminate the fault; Confusion: It is possible that due to the misalignment of the fire line or the misinstallation (position), the individual cylinder or multiple cylinders do not work properly or do not work, etc., it is recommended to reinstall the high-voltage line of each cylinder in the ignition order.

Distributor failure: Internal failure of the distributor, such as centrifugal block jamming or other defects. The ignition time was not properly advanced, resulting in the ignition being too late and the exhaust pipe "firing". Recommendation: Repair such as grinding, lubrication, or direct replacement (as applicable).

Spark plug: Due to the decrease in the ignition efficiency value of the spark plug, the unburned mixture enters the exhaust pipe and burns and "discharges". Recommendation: Check one by one and replace the faulty parts (spark plugs).

It is recommended to drive the car to a 4S shop for maintenance and inspection.

Due to the high temperature inside the engine, the generated water is discharged in the form of water vapor, and when it reaches the tail of the exhaust pipe, it encounters cold air outside before forming liquid water flowing out of the exhaust pipe. If water is sprayed or outed when the car is idling or when you press the accelerator, it is a sign that the gasoline is burning very well in the cylinder.

If the exhaust gas is white in the summer when the outside temperature is high, it is not normal. The exhaust pipe expelling white gas in the summer proves that the engine burns coolant.

Engine Considerations.

Thirty seconds after the engine starts, the condensed oil is sent to the pistons, connecting rods and crankshafts that need to be lubricated the most. And for the engine to reach the normal operating temperature, it takes 7-10 minutes. The main purpose of the hot car is to send the oil that has been condensed below to the surface that needs to be lubricated through the oil pump pressure and the rotation of the ring, and the engine has been running for 30-60 seconds.

Idling and warming up the car for a long time in place is not only limited, but the gearbox and other stationary parts are not warmed up, so the preheating is very limited. Idling in place for a long time to warm up the car also wastes gas and time.

Let's talk about buying a car, using a car, maintaining a car, and repairing a car.

The common fault points of unstable car idling are as follows:

1.Leakage from the intake manifold or various valves.

When the air intake of the engine is not right, the mixture will be too thick or too thin, so that the engine burns abnormally. This can cause the engine to shake at idle.

When the air leakage position affects the vacuum level of the engine, the engine will shake violently, which will have a greater impact on the idle speed of the cold car.

Common causes include: air leakage due to aging of the intake manifold pad, damage to the intake manifold or other parts grinding out of the intake manifold, vacuum tube plug falling off, ruptured exhaust gas recirculation (EGR) valve is not tightly closed, etc.

2.Excessive fouling of the throttle and intake.

The excessive carbon and dirt deposits in the throttle valve and the surrounding air intake, and the change in the cross-sectional area of the air channel, make the control unit unable to accurately control the idle air intake, resulting in the mixture being too thick or too thin, and making the combustion abnormal.

The common causes are: throttle carbon deposit, oil and carbon deposits in the intake tract around the throttle.

3.Idle air actuator failure.

Inaccurate idle air control due to a faulty idle air actuator.

Common causes are: throttle motor damage or card issuance, throttle valve plate due to carbon deposits causing jamming.

4.Inaccurate air intake.

The control unit receives the wrong air flow sensor signal and sends out the wrong command, which causes the engine idle air intake to be inaccurate, and the abnormal mixture concentration makes the engine burn abnormally, which is the indirect cause of idle instability.

Common causes are: air flow meter or its line failure; Failure of the inlet pressure sensor or its wiring; Caused by poor wiring harness contact of the engine control unit or failure of the engine control unilateral side itself.

When the vehicle has an unstable idle speed, it is recommended to check the above components.

Hello, there is a sudden sound in the exhaust pipe when idling, which is not normal and should be overhauled.

There are two reasons for the sudden burst, one is that the external --- exhaust pipe is rotten and the other is sick --- internal machine must first replace the breakdown spark plug, the three-way catalytic converter of the high-voltage line will not cause the sudden sound, and if the high-voltage line is aged, it will cause your car to be uneasy and your car to be bored. The three-way catalytic converter can only cause your exhaust gas to be unqualified. I judge that now you have only one reason: your car now has a cylinder that is not functioning properly.

It's the cylinder of the broken spark plug. Let's take a look at the 4S store.

Abnormal.

There are two causes for the suddenness:

An external exhaust pipe is rotten.

If an internal machine is sick--- the spark plug must be replaced first, the three-way catalytic converter of the high-voltage line will not cause a sudden sound, and if the high-voltage line is aged, it will cause your car to be uneasy and your car to be bored. The three-way catalytic converter can only cause your exhaust gas to be unqualified. Let's take a look at the 4S store.

When idling, you feel a sudden sound in the exhaust pipe, indicating that the engine is not burning well. It is necessary to start with combustion and three-way catalytic emissions, and if the three-way catalysis is not damaged, it can be passed by directly lifting the combustion.

There are 1 cleaning three-way catalysis 2Clean the oxygen sensor 3Directly improve fuel quality4To clean the oil circuit, use Add 5Find someone to check on behalf of 6High-efficiency and alkaline cleaners to clean the combustion chamber – not recommended and can damage the piston rings and oil seals.

To clean the oil circuit, the company has a general fuel additive cleaning two-way curing agent can prevent and remove carbon deposits in the oil circuit, prevent car shaking, and prevent abnormal automobile exhaust.

Summary. Here are the causes of vehicle idle jitter: 1

Severe carbon deposits in the engine: the mixture that leads to cold starts is too thin, making it difficult to start. 2.

Ignition system problems: Ignition system is not working well, spark plug flashing condition is not good. 3.

Unstable oil pressure: The oil supply pressure of the oil pump is abnormal or the value of the inlet pressure sensor is wrong.

The following are the reasons why the vehicle is idle and shakes highly: Sail Model 1Serious carbon deposits in the engine:

The liquid car scale mixture that causes a cold start is too thin, making it difficult to start. 2.Ignition System Issues:

The ignition system is not working well, and the spark plug is not in good condition. 3.Oil pressure is unstable:

The oil supply pressure of the oil pump is abnormal or the value of the inlet pressure sensor is wrong.

If you have cleaned the engine carbon deposit, washed the throttle, changed the oil cushion and spark plug, etc., and still found that the body shakes when idling, it is recommended that you go to the 4S shop to check whether the fuel supply pressure and intake pressure sensor are normal.