A Volkswagen Polo Jin take the car, hand automatic 6 block 09G transmission.
    Symptom: exhaust manifold red body. Especially the three-way catalyst on the oxygen sensor installed roots were burned red, exhaust choking.
    Troubleshooting: After receiving the car, first open the engine cover. Look at the exhaust manifold above the full red, steaming. High temperature baked people. According to the owner. Morning start time. Hear the engine compartment "bang" soon after. The engine is running on the wrong, idling high, power down. Encountered in front of the roadblock, the emergency brake, brake pedal stepped on. The car can not stop, scared the owner did not dare to open again. From the owner to provide symptom information preliminary analysis: ① brake pedal hard. Most of the vacuum pipe leak; ② exhaust pipe red is generally mixed with thick gas Erzhi. Because the model is 16V-HLD intelligent logic control engine, engine management system (ME75.20). Displacement 1.6L, model BMH. Chain drive system, four-valve roller hydraulic valve, VVT valve timing adjustment mechanism, dual thermostat cooling system, crankcase ventilation and vacuum pipe structure has been changed. I have the engine of the model has not really repaired, know very little Lack of experience, the specific reasons for further examination, by the table and in. First on. A. G1552. Enter 01 address, display 03C906057CH019082AT / 1.6-4V / 77KWcodirlg0000075 * P *. Enter 02 fault query. FaultSource18711refiereces is a reference failure. It seems VA. G15526.0 version is low, can not identify the true meaning of the fault code, only then connected to the V. A. S5051 diagnostic apparatus. Check the fault code 18711 - air intake system leak, can not clear code. Idle operation, into the 01-08-002 group, 960r / min, the engine load 24%. Fuel injection pulse width 9.8ms.
    From the data flow point of view idling high, the standard is 760r / min, fuel injection pulse width is 3 times normal, the mixture is too strong, the combustion of gasoline in the combustion chamber is not complete. The rest of the gasoline went to the exhaust manifold to burn. The car exhaust manifold and three-way catalytic converters are integrated into one. Oxygen sensor installed in the three-way catalyst, the exhaust manifold was burned red, will lead to three-way catalyst sintering plug, at the moment the engine body temperature is unusually high. Spark plugs will burn. Even the ignition coil is at risk of explosion. The consequences will be disastrous. According to the fault code. Check that all connection pipes in the intake system are reliable or missing. Idle operation close to the engine, can hear the creak of the air, which is the timing of the chain rhythm of the rhythm is significantly different. Because the fault symptoms and vacuum power related. Remove the air filter cover. Remove the air filter cartridge from the air filter cover right corner side of the channel from the top down to see a variable section - from large to small holes, can see the translucent, and then carefully check from the vacuum booster pipe to the air The check valve in the lower right corner of the filter. It is integrated with the three links, vertical down the mouth of the channel has three guide groove is clearly used in the plug, but at the moment there is no insert shaped rubber hose. Vertical up the mouth to the air filter cover (the above from the big hole), the left is a one-way valve to the vacuum booster, then the vertical down the channel should be where the pipeline? Triggering the author's interest, to explore what happens.
    The car lifted up in the lift from the bottom up, throttle body under the plastic inlet box has three plugs, two pipe plugs with rubber hose. Close to the throttle body plug is empty, no plug, from here can basically judge, the rubber hose should be from the plug to the air filter on the three-way one-way valve body, this pipe is to the vacuum booster With the vacuum, then where is the pipeline in the engine compartment. Look carefully. And finally in the firewall side of the air conditioning between the high and low pressure pipe found this root hose. Insert this root is missing the hose, start the engine, clear code, read the data stream. Idle 760r / min, fuel injection pulse width 3.3ms, exhaust manifold no longer red, and brake help. After the test, all returned to normal. Eliminating the worries of the owner.
    Fault Summary: Why the vacuum tube will fall between the high and low pressure pipe. unknown. But the leakage, causing the rear of the throttle body leakage, intake manifold vacuum drop, the pressure sensor signal voltage becomes larger. Increased injection pulse width. The mixture becomes thicker. Burning is not complete, the results of gasoline burned to the exhaust manifold, so that emissions exceeded. "Bang" is a cold start in the morning mixture of thicker, exhaust pipe blasting, on the other hand, due to leakage vacuum booster can not get a vacuum, causing the brake pedal step forward.