What should I do if the cold car does not idle, but the hot car idles too much

The inspection items such as the car cannot start, the idle speed is unstable, the speed is high and low, and the oil supply is abnormal, etc., as follows: 1. The car battery voltage is low; Specific detection method: test the battery voltage with a three-purpose meter voltage level, if it is below 10V, it is recommended to replace it.

If it is around 11V, it is barely used; Be prepared for replacement. It can be used above 12V; 2. Check whether it is caused by carbon deposits; If you travel about 20,000 km, focus on checking and cleaning the throttle; 3. Inspect, test and replace spark plugs; 4. Confirm the quality of the gasoline added; 5. Detecting the ignition switch; 6. Test and detect the starter, gasoline pump, sensor and other related components of the starting and oil supply system; 7. After powering on, do not start immediately, wait for 30 seconds to 1 minute, and then ignite; Let's see if it works. The idle speed is not easy to drop, so you can check whether you should clean up the carbon deposit.

1. Too much carbon deposition in the throttle and air flowmeter is still relatively easy to get dirty, and a little carbon deposition may affect it, and excessive carbon deposition in the throttle will cause the accelerator to be stuck, the power will drop seriously, and the idle speed will be unstable.

2. There is too much carbon in the combustion chamber of the cylinder, which will have a certain adsorption effect on gasoline, and too much carbon will be formed, most of which will be formed on the valve and piston ring, which will indirectly cause the cylinder pressure to be insufficient, and it will be easy to idle and unstable when the cold car starts, and the hot car will be good.

If the engine is unstable when the engine is running cold, it is easy to stall, but the idle operation is basically normal after the hot car, and the reasons are usually as follows:

When the additional air valve is not opened or the opening is too small, the idle speed of the engine is too low when the engine is cold, resulting in unstable idling.

When the engine is cold, the idle control valve is faulty, and the opening is too small, so that the idle speed is too low when the engine is cold, resulting in unstable idling.

The water temperature sensor is faulty, so that the engine computer does not increase the idle speed and thicken the mixture according to the engine temperature when the car is cold, resulting in unstable idling.

The injector is poorly atomized or partially blocked, which makes the quality of the mixture deteriorate or the amount of fuel injected is too small under the idle condition of the cold car, resulting in the mixture being too thin and causing the idle speed to be unstable.

The main fault is the carbon deposition of the idle motor and the ignition timing.

You can go to the maintenance shop to clean the idle motor, in addition, after the idle motor is cleaned, if the starting effect is not improved much, then check the distributor, if the ignition time is not in the standard range, there will be unstable idling, otherwise you can adjust it.

According to the above-mentioned vehicle use phenomena, combined with your vehicle condition and maintenance cases, the main thing is the fault of carbon deposition and ignition timing of the idle motor. Therefore, it is recommended that you go to the repair shop to clean the idle motor, in addition, after the idle motor is cleaned, if the starting effect is not improved much, it is recommended to check the distributor, if the ignition time is not in the standard range, there will be unstable idling, otherwise you can adjust it. In summary, it is recommended that you go to the repair shop to check the above repair suggestions, I hope it can help you.

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After this phenomenon occurs, this is mainly because the throttle is dirty, and the throttle valve appears slightly stuck after the cold car starts, and this phenomenon will appear, and the throttle needs to be cleaned, and the computer can match it after cleaning. This can be solved, if there is still this phenomenon after matching after cleaning, then you need to check the spark plug, check that the engine cylinder has more carbon, and it also needs to be cleaned.

The main reason for the instability of the car idling is the leakage of the intake manifold, when the air, gasoline vapor and combustion exhaust gas that should not enter enter the intake manifold, resulting in the mixture being too thick or too thin, causing the car to idle unstable.

1. When the air intake manifold leaks, when the air, gasoline vapor and combustion exhaust gas that should not enter enter the intake manifold, the mixture is too thick or too thin, causing the car to idle unsteadily. The car owner can identify whether there is an air leak in the intake manifold by opening the engine compartment cover and removing the air filter of the throttle.

Start the car and block the throttle with your hand (if the car stalls after the blockage, it means that there is no air leak, if it is not stalled, it means that there is an air leak somewhere). If there is no flameout, there is no need to rush to extinguish the flame, at this time, check the nearby pipes to see if there is any inhalation, if there is inhalation, it means that it is leaking.

2. Excessive carbon deposition on the throttle: excessive carbon deposition in the throttle 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, and also cause the mixture to be too thick or too thin, resulting in unstable car idling.

3. Failure of the actuators of the intake system: There are many actuators of 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 idle speed of the car to be unstable.

4. Fuel system failure: Fuel injector blockage, fuel filter blockage, fuel pump filter blockage, fuel pressure regulator failure, oil return pipe blockage and other faults will lead to incorrect fuel injection, resulting in over-concentrated or over-thin mixture, resulting in unstable car idling.

5. Ignition system failure: ignition module failure, incorrect spark plug clearance, spark plug electrode ablation or damage, high voltage line resistance and other faults lead to ignition spark energy decline or misfire, resulting in unstable car idling. If the car has an unstable idle speed, then it should be dealt with as soon as possible, knowing that the engine is no longer at the ideal idle speed, and the fuel economy and environmental protection will deteriorate.

Dear Kiss Glad to serve you Cold car without idle speed The normal reason for hot car is that the additional air valve is not opened or the opening is too small when the car is cold, so that the engine idles violently when the car is cold, and the speed is too low, resulting in unstable idling. Or the idle control valve is faulty when the engine is cold, and the opening is too small, so that the idle speed of the engine is too low when the engine is cold, resulting in unstable idling. Another reason may be due to the quality of the oil being filled.

The first thing is low temperature in cold start, and the temperature in the engine is not enough, so more fuel should be injected to meet the requirements of power during cold start. The larger the gap between the spark plugs, the smaller the ignition energy. When the fuel atomization is not good at low temperature, the fuel needs higher ignition energy, and the ignition gap of the spark plug is easy to become larger when the car is used for a long time, resulting in a decrease in ignition energy, which affects the dynamics and makes the car shake.

In addition, the ignition energy can also be reduced due to the aging of the ignition coil, the aging of the high-voltage line of the spark plug, or the leakage. The mixing ratio of oil and gas is not accurate, which exists in both open-loop and closed-loop control. If the car computer makes a mistake in judgment, there is an error in the control of the oil and gas mixing and ignition time through the actuator, thereby reducing the power output of the car and causing shaking.

In addition to the above-mentioned faults, there are other factors that can also cause the car to shake badly when it starts cold, such as the failure of the water temperature sensor, the difference in the working conditions of each cylinder, and so on. These faults cannot be solved by themselves, and they need to be repaired by a professional repair shop or 4S shop.

1. The engine has serious carbon deposits. Excessive carbon deposition inside the engine is one of the common causes of idle runout, and in the case of excessive carbon deposition, the gasoline ejected from the fuel injector during cold start will be absorbed by a large amount of carbon deposit, resulting in a diluted mixture during cold start, which will make cold start more difficult. It is necessary to clean up the carbon deposits in time, clean the oil circuit regularly, and check whether the working condition of the idle motor is normal.

2. Ignition system failure. Idle runout may be due to ignition system failure, such as spark plug damage, need to be replaced, in addition, there may be a problem with the high-voltage wire and ignition coil, which can be judged by the car computer and then repaired.

3. The oil pressure is abnormal. The fuel supply pressure or intake pressure sensor may be abnormal, causing the body to shake and need to be repaired in time.

4. Aging of engine parts. Aging engine components, such as engine feet, can directly affect the engine's damping system, transmitting vibration to the cab and steering wheel, resulting in idle runouts that require replacement of parts.

5. Fuel quality problems. The fuel quality is poor and not burn-resistant, which not only increases fuel consumption, but also causes idle vibration and needs to be replaced.

6. The throttle is dirty. Dirty throttle will cause jamming in throttle opening and closing, resulting in idle vibration, and the throttle needs to be cleaned in time.

7. The water temperature sensor is out of order. The water temperature sensor is one of the important bases for the computer to judge the working condition of the engine, if it fails, the amount of fuel injected in the system will also be inaccurate, resulting in jitter at idle, and the water temperature sensor needs to be repaired.

8. The air flow meter is dirty. The air flow meter is dirty, which may lead to a decrease in the air intake, which indirectly causes the vehicle to jump when idling, and the air flow meter needs to be cleaned in time.

9. Injector failure. If the injector is stuck, blocked, and poorly sealed, it may cause uneven cylinder injection and poor atomization, and the output power of each cylinder will also be uneven, resulting in idle runout, and the injector needs to be repaired.

10. The engine idle speed is low. The engine itself has a low idle speed, such as less than 600 rpm, which may also cause the body to vibrate, and the idle speed needs to be adjusted.

1. Too much carbon is deposited on the throttle and air flow meter.

Throttles and air flow meters are still relatively easy to get dirty. Most cars today are electronic throttles. Small amounts of carbon deposition may affect them. Excessive carbon deposition on the throttle may cause the fuel throttle to jam, power drop, unstable idling, etc.

2. Excessive carbon deposition in the cylinder combustion chamber and piston!

There is too much carbon deposit in the combustion chamber of the cylinder, which will have a certain adsorption effect on the gasoline! So it will take a little longer for the ignition to start!

In addition, excessive carbon deposits will be mainly formed on the valve and piston rings, which will indirectly lead to insufficient cylinder pressure! A cold start can easily lead to unstable idling, and a warm car will eliminate these symptoms!

Remind everyone to pay attention to the carbon deposition cleaning and throttle cleaning of the engine when repairing. The more kilometers you run, the more you know how important it is!

There are several reasons why the idle speed of the cold car is unstable when it starts:

1. Caused by excessive dirty throttle;

2. Caused by the failure of the oxygen sensor;

3. The water temperature sensor is faulty;

4. Caused by excessive carbon deposition in the spark plug.

The vast majority of this may be the throttle valve needs to be cleaned, the requirements for the air-fuel ratio of the engine are relatively high when the car is cool, the lack of air intake will cause the mixture to be too thick and difficult to burn, and the requirements are relatively low when the car is hot, so it is better to start some, you can first consider washing the throttle to observe it, I hope it can help you.

Volkswagen's common problem, the cold car throttle is not sensitive, when stepping on the accelerator, I feel that the car is very reluctant to go, and the front suspension makes a weird sound, but after the car is hot, these problems are gone

The temperature of the engine is different when the cold car and the hot car are different, the mixed gas atomization is good when the hot car is hot, and the combustion is sufficient, and the idle speed is based on the hot car state, because the normal use is a hot car, in the cold car due to the mixed gas atomization is not good, the idle speed will be unstable or no idle speed due to the poor combustion of the mixture, so it is necessary to use the damper to start and preheat at this time, if the idle speed is adjusted up when the cold car is cold, it will be relatively normal, but the idle speed will become too high after the combustion conditions are improved after the hot car. The idle speed is determined based on the standard when the car is hot, and it is normal for the idle speed to be unstable, low or no idle speed when the car is cold.

1. Introduction to air flow meter.

The role of the air flow meter.

The air flow meter measures the amount of fresh air entering the engine intake manifold and the intake air temperature, and the ECU uses this information to make injection corrections, smoke limits, and EGR opening control.

2.Installation location.

The sensor is mounted on the engine intake duct and at the rear end of the air filter.

3.How it works.

The principle of an air flow meter.

The air flow sensor is to integrate some electronic components on a ceramic substrate, when the engine is working normally, the diaphragm is first heated, and the fresh air flows through the sensor will take away part of the heat, at this time the ECU will control the Wheatstone bridge on the diaphragm to supplement the diaphragm, which will cause a change in the electrical signal, when the signal is transmitted to the ECU, the ECU will calculate the air intake according to this change.

The principle of the air temperature sensor.

The inlet air temperature sensor is a negative temperature coefficient resistor, when the inlet air temperature changes, the resistance value of the resistor will change, causing a change in the signal voltage at the ECU terminal, and the ECU calculates the inlet air temperature based on this change.

Determination of the direction of the airflow.

There is a same temperature resistance at both ends of the hot film of the air flow meter, and when the air flow flows through the hot film, it will take away part of the heat, so the temperature at the front end of the hot film is lower than the temperature at the rear end, and the ECU judges the direction of the air flow according to this signal!

4.Wiring diagram of an air flow meter.

5.Control policy.

The ECU will monitor the working condition of the air flow meter at all times, and when the ECU judges that the air flow meter is faulty, it will take corresponding control, as follows.

The engine mil light is lit, the EGR system is withdrawn from work, and the exhaust gases will no longer participate in the system work;

The engine speed will be limited to a certain speed, and the power will be limited;

When the air flow meter fails, the engine start is not affected and can be started normally;

Second, the detection of air flow meter:

Fault codes related to air flow meters.