Vacuum leakage fault phenomenon and analysis (2)
Vacuum helium failure phenomenon and analysis under Baotou Li Guide type fuel injection engine This mainly includes the blade-type center-type Cartan type air flow meter configuration of the engine. Example Toyota Camry, 3VZFE made, fault phenomenon is unstable, speed up and powerless. The fault light is on. Fault detection first retrieves the fault code. To 45 mixture too thin; 12 air flow meter bad. At idle, the air flow measurement signal is about 0.6V. Deviation from the standard value 1. More. The low flow of the air flow meter will inevitably result in a decrease in the amount of helium and a too small mixture. So, what is the reason for the low number of air flow meter nicknames, based on experience and analysis. There are roughly two points, vacuum leaks. Air flow meter failure. First check from the leak, no obvious leaks. The vacuum was measured at idle speed to 52.633 and the manifold vacuum 1 was normal. Illustrates gas after throttle. Careful examination revealed that the main airway and throttle joints were loose. After re-tightening, the engine performance became significantly better, and then the air flow meter signal was 1.27, normal. The fault light goes out and the fault is eliminated. Fault Analysis The air flow meter of this car is a leaf type, and the blades are rotated. At the same time, the apron drives the potentiometer contact to slide to a position where there is a nickname of the amount of air input to the computer. Due to air leakage. It has not been measured by an air flow meter, so the turning angle of the blade is reduced. That is, the signal becomes smaller, causing the mixture to be too thin. Why is it normal to check the vacuum level? This is because at idle, the throttle valve is fully closed. The air entering the manifold can only pass through the air valve next to the idle valve. The leakage before the throttle valve is independent of the vacuum in the manifold. It is found that the degree of vacuum is low and it is important to check whether there is a leak after the throttle. Example 2. Lexus 15400 Symptoms Idle speed is too high. Fault detection first retrieves the fault code without a code. Read data stream D5,1010, found from the data stream. The throttle is fully closed at idle speed. Is normal. The idle switch is in the off position, indicating that the computer is not considered idle at this time, and it will not adjust the idle speed with idle conditions. Adjust the position of the valve sensor so that the speed drops to around 1000 yo and no longer drops. Continue to read the data flow and find the step-by-step data as if the step-type idle valve is faulty if the idle valve fault or the computer-to-idle valve The head of control. It will be possible to increase intake 3 and increase the speed. For prudence. Turn off the ignition switch. Restart the engine and continue to observe the data flow discovery. The valve gradually decreases from 125 steps to 0 steps at the start. This shows that the idle valve is good and working properly. The adjustment from step 125 to step 0 shows that there is a leak, and this extra air has passed through the air flow meter to adjust the idle speed to the limit, and it cannot be adjusted to the standard idle speed, so the speed is still high. Remove the throttle air hose and find that the throttle has been opened at an angle. Normal The throttle valve should close completely. The excess air flows from the throttle. This is caused by improper adjustment of the bit screw, so that the throttle is closed, and then re-adjust the throttle position 3 sensor position, so that the sensor idle contact closure, while leaving the sensor at idle signal at about 5, the adjusted idle speed Speed ​​is a fault analysis Lexus LS400 is equipped with a Karman vortex air flow children's meter 3 With the change of the air 1 flow, the signal frequency of the pulse frequency of the code number is about 18, when the speed increases, the signal frequency It also rises up to 300 or so. If the voltage is used to measure the average voltage of its signal. Should be 2.53, fluctuations. This voltage value is not affected by the speed, 3 open the ignition switch without the car! In the case of this signal frequency, the voltage of this signal is due to this vehicle's leak at the throttle, and this extra gas passes through the air flow meter to measure the drought. At this point the air flow meter signal must be greater than the normal idle signal, so the computer will increase the amount of fuel injection. Causes the engine speed to rise. In order to control the idling speed, the computer will control the idling valve to close the small air passage. However, due to the large air leakage, the idling valve is completely closed. The air flow meter that can not be converted to a summary analysis type fuel injection engine configuration is still a direct measurement type. However, the type of fuel injection engine. Configured with intake pressure sensor. Indirect measurement type. They belong to the detection part of the air volume. However, their detection methods are essentially different. When the manifold vacuum leaks. The current form of engine failure is also very different. When detecting such failures. First of all, it should be clear what kind of air measurement components are installed in the engine. Then according to the phenomenon of failure. To analyze the location and size of the leak. As long as the thinking is clear. Troubleshooting is also simple and accurate. Under normal conditions, the air flow meter signal increases with the increase of the intake air amount and is a positive characteristic. When there is a vacuum leak. The location of the leak and the amount of excess air measured by the flowmeter should be analyzed based on the faulty phenomenon, as this excess gas is not measured with an air flow meter. The amount of fuel injection did not increase, and the increase in air volume caused the mixture to be too thin. It will cause the engine to idle fast, accelerate and fail to fire. As an example, the amount of excess air measured by the flowmeter is dirty when the idle valve in the bypass airway is stuck. The idle valve is damaged. When the idle control is out of control, there will be excess air entering the manifold. When in the main airway. If the throttle is improperly adjusted or the throttle cable is too tight, excess air will enter the manifold. Since the inner leakage gas is measured by the air flow meter. The computer then increases the amount of fuel injected. This will cause the engine to increase in idling speed. When the air leakage is large, the speed is increased to a fixed speed 2000. The overspeed shut-off function will be started. There is an idling tour. , Type of fuel injection engine is mainly hot-line and hot-film engine example 1 day production glory 32 fault phenomenon idling instability. Easy to turn off when starting. Failure detection for no reason, code, in the routine inspection, spark plug spark. Fuel pressure is normal. When measuring the signal of the empty 1 flowmeter. Only deviation from the standard value of 1. More than 37, indicating that the engine idling instability, the lack of power is caused due to too thin mixture. Remove the air flow meter. After rinsing the hot wire with the carburetor cleaner, install the test vehicle. The fault still proves that the air flow meter is not too low in signal voltage due to overheating of the hot wire. The reason why the air flow metering signal is too low may be air leakage, which was found when measuring the manifold vacuum. The vacuum pressure is 50 ports 3 standard 278, 3. Check the vacuum tubes did not find any question, use carburetor cleaning agent to the interface test, found that the throttle body and the manifold at the bubble, the original is the last time to clean the throttle. Improper installation of sealant produces air leakage. After processing, troubleshooting. Failure Analysis Since the vacuum leak is behind the throttle, it is not controlled by the idle valve. The manifold vacuum will drop. At the same time, it has no measure of air flow. Instead, due to a vacuum leak. The idle valve will close at this time. The main airway flow is reduced accordingly. This will cause the air flow meter signal to weaken. Reduced fuel injection. More air. Mixture gas will inevitably become thin due to insufficient engine power. Case 2 Nissan Maxima 1 Symptoms Idle speed is too high. The fault detection begins with the idle speed valve. When this car idle valve is stepping, it feels that this idle valve motor compartment vibrates. Indicates that the computer control is valid. Remove the idle valve. Found more internal sludge. After cleaning with carburetor and lotion, the test vehicle was installed and the fault persists. Note that the idle speed control valve is not out of control because of a dirty card, and the idling speed valve group coils are still good. The idle valve was not asked. When the idle valve plug was measured, the computer's output was normal. The group control ground wire group is always grounded, this is the cause of the stepper motor is always stopped a certain position, look at the computer and found that the wire was shielded damaged ground, this line is the stepper motor group Control the ground wire and handle the mouth. Troubleshooting. Fault analysis is speaking. Idle speed is mainly due to the loss of control of the idle valve. Dirty card caused. Another reason is the throttle leak. The air flow meter signal also increases and the injection volume increases. Speed ​​increases. When the leakage is large. When the idle valve is closed to the minimum position, it is not enough to reduce the speed to the standard value. The reason for the failure of this car is that the idle valve is out of control and stays at a certain position. More air is measured through the air flow meter and smoothly enters the manifold through idle speed, causing the engine speed to be too high to be controlled. The small knot type fuel injection engine is based on an improved fuel injection engine. They all belong to the engine control system that is connected to Huanghua Air. However, it is the hot-wire or hot-film air flow sensor that is used for the helium type. Its measurement accuracy is higher than that of the model. The fault occurs when the vacuum leaks. The faults that they present are roughly equivalent to the most simple and simple fault phenomena. That is, the multi-helium gas measured by the meter is diluted by the mixture gas. Unsteady idling will occur. Lack of motivation. Easy to turn off. The measured excess gas is increased due to the increase in the air flow meter signal, and the mixture is richer than normal. The idling speed will be too high, resulting in a fuel-cutting phenomenon. Vacuum leaks are more common failures. It is not difficult to find through the above types of fault instances that due to the different locations of vacuum leaks and the magnitude of vacuum leakage in various models, the fault phenomena they cause are also different, as long as maintenance personnel have mastered the configuration of various types of vehicles. Features and vacuum parameters, and then based on the analysis of the fault phenomenon, will determine the smoother fault location and faulty components. Cutting Torch Tips Gas Cutting Nozzles,Gas Plasma Cutting Nozzles,Flame Gas Cutting Nozzle,Plasma Gas Cutting Nozzle Changzhou Edaweld Trading Company Limited , https://www.edaweld.com
As in welding, you must use the proper size cutting tip if quality work is to be done. The preheat flames must furnish just the right amount of heat, and the oxygen jet orifice must deliver the correct amount of oxygen at just the right pressure and velocity to produce a clean cut. All of this must be done with a minimum consumption of oxygen and fuel gases. Careless workers and workers not acquainted with the correct procedures waste both oxygen and fuel gas.
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