02 POLO 1.6 The idling jitter temperature of manual hot car rises slowly, sometimes high and sometimes low. Ask! !
The most common fault of the old 1.6 Polo car is car shake. Here, I will first rule out the obvious causes of car shaking, such as the broken ignition coil (phenomenon: the car will shake violently because of the lack of cylinder until the flameout) and the problem of adding oil. I only analyze the car shake caused by the design of this car. 1.6 polo designed the exhaust gas recirculation system (EGR) because of environmental problems, but other polo models did not design this system, which is unique to 1.6 car. The basic principle of the exhaust gas recirculation system is to re-introduce the exhaust gas generated by the engine into the intake system of the engine for re-combustion, thus purifying the exhaust gas. The system consists of a metal exhaust pipe and an exhaust gas recirculation valve. The exhaust gas of the engine is connected to the inlet of the exhaust gas recirculation valve through a metal exhaust pipe, and the outlet of the exhaust gas recirculation valve is connected to the throttle valve. This exhaust gas recirculation valve is actually a solenoid valve, which is controlled by the instruction of ECU, that is, ECU decides how much exhaust gas enters the throttle valve. Under normal circumstances, the exhaust gas produced by the combustion of mixed gas in the engine is sent to the oxygen sensor, and the oxygen sensor corrects the ECU fuel injection quantity according to the content of various indicators in the exhaust gas to ensure the normal concentration of mixed gas in the engine, that is, the specified air-fuel ratio. The concentration meter of the whole mixture is calculated by ECU according to the data of various sensors, including the amount of exhaust gas re-entering the intake system to participate in combustion, which is dynamically balanced. As long as it is balanced, the whole system will work normally. When ECU informs the exhaust gas recirculation valve to let the exhaust gas enter the throttle to participate in reburning, if the system has air leakage, no gas, etc. However, the exhaust gas that needs to enter the throttle valve for reburning does not enter according to the quantity, which will cause system disorder. The ECU will constantly adjust, but the car will shake slightly at this time. This shaking will not affect driving, but it is indeed a problem. Knowing this process, jitter is the shortage of intake exhaust gas caused by air leakage or no air in the exhaust gas recirculation system. The solution is to check whether the metal exhaust pipe, the joints of the system and the exhaust gas recirculation valve itself are stuck, which will cause air leakage or air intake (the exhaust gas recirculation valve is stuck due to carbon deposition, so that the exhaust gas of the engine cannot enter the throttle normally according to the requirements of ECU).
In order to solve this problem, Shanghai Volkswagen once ignored that the ECU was too sensitive to the exhaust gas recirculation valve by modifying the parameters of the ECU, which led to the problem that the oxygen sensor reported that the left circuit of the oxygen sensor cylinder S 1 was faulty and intermittent. This problem was avoided by replacing and upgrading the ECU. So many cars with upgraded ECU have obviously solved the problem. I think this is actually just to avoid this problem rather than solve it. The real solution is to clean the EGR valve. The exhaust gas can smoothly enter the air intake system for reburning, and there is no air leakage loss in the middle, and the mixture concentration is naturally normal, and the idling speed does not shake. The reason of sloshing is that the exhaust gas does not enter the intake system, and the idling fuel injection is certain, which makes the mixture concentration too high, the combustion is insufficient, the exhaust gas smells bad, and the fuel consumption is greatly increased. After this treatment, the tail gas smell of the exhaust pipe is basically normal at present, and the exhaust pipe sprays water, indicating that the combustion is good and the tail gas meets the standard. All friends with similar problems might as well try this method. I think it will have an immediate effect.