A Toyota previa (PREVIA) Caravan fuel supply method for electronic control multiple-point fuel injection fuel, engine idle speed for 850R/min (not low), ignition advance angle of 120, violent shaking when idling, speed increases after dithering until flattened. 2400r/min above when running at high speed, basic working properly.

Engine shaking is not uncommon in electronic fuel injection system, this type of problem is provided by engine cylinders work evenness Analyzer analysis, you can quickly find out why. First check the spark plug. 4-cylinder spark plug is good, no Coke, no electrode erosion phenomena and electrode gap is also normal. Bosch (Bosch) produced by MOT250 Analyzer, first observe the primary and secondary ignition electronic ignition system circuit diagram, focusing on the secondary cylinder ignition waveforms, including ignition peak (high pressure 1, ignition timing and angle parameters, from the waveform analysis, ignition system and there are no exception. Followed by the respective cylinder and homogeneity of the fuel injector fuel). Print results, 4th cylinder water f does not work at 1 o'clock the engine speed does not decline, but rose gradually easing and jitter: AHC test results showed that the 4th cylinder fuel consumption is much lower than the remaining 3 cylinders. Thus preliminary troubleshooting for the 4th cylinder work is poor. Other cylinder fuel injector to the 4th cylinder, idle is still dithering. This shows that the working poor is not due to nozzle why (conditional repair shops can use the fuel injector test bench, injector testing and cleaning work carried out). Cylinder head (including Wei guarding combustion chambers and valves, to rule out any cause of the malfunction, but is not ruled out.

Disintegration of the engine again to detect the cylinder deformation, causing combustion chamber compression ratio changes. In the process, found that exhaust gas recirculation system introduced in the 4th cylinder on the intake manifold. Using exhaust gas recirculation system to reduce engine emissions of harmful gases, which stems from the part of the exhaust gas in the exhaust pipe and can be controlled by valves, into the air intake system of exhaust flow and timing the best adjustment is performed. At idle speed and low load conditions (nitric oxide production). Exhaust gas recirculation flow is zero f exhaust gas recirculation valve closed).

The car exhaust gas recirculation system fails, in idle state, the exhaust gases are entering the 4th cylinder (because it is near the exhaust gas recirculation system introduced recently), increase the number of exhaust gas in the cylinder, thus affecting the normal work. Because the exhaust gas recirculation system breakout from the 4th cylinder exhaust valve recently, HC test, 4th tank for Jet fuel was cited for recycling, while detecting injection quantity, 4th cylinder is much lower than other 3 cylinders. Exhaust gas recirculation system after the import and export of asbestos mat blocked, idle vibration troubleshooting.

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