A Santana 2000 sedan, engine model AFE, mileage 220,000 km.
    The car changed the engine assembly due to burning oil, factory a week later to plant maintenance accelerated bad. Black smoke. With the fault diagnosis V. A. G1552 into 01 group 02 function check, display fault code 00525, indicating that there is no signal output G39 sensor failure. And then use V. A.G1552 into 01 group 08 function 07 to read the data block, the second area shows the voltage is 0.45V, which is the oxygen sensor after the replacement of the signal. After replacing the oxygen sensor, the black smoke troubleshooting, but the road test still feel the acceleration is not smooth. With ultrasonic cleaning nozzle after the atomization test, ruled out the fuel nozzle factors. After the replacement of the fuel filter, the fault slightly improved, but still not ideal. Mainly in: the engine in the parking without load when the smooth running conditions, start driving low-speed refueling when the break, and good times and bad, but the speed of 80km / h or more when the engine is working properly.
    Check the engine cylinder pressure, l cylinder to 4 cylinder cylinder pressure were 1.15MPa, l. 18MPa, l. 32MPa, 1.25MPa, because the AFE engine compression pressure requirements of 1.00-1.30MPa, and the cylinder pressure should not be greater than 0.30MPa. The test results show that the engine cylinder pressure is normal.
    Next check the fuel pump oil and operating voltage. First pull out the central electrical board on the 2nd relay, connected to the fuel pump remote control V. A.G1348 / 3A and 1348 / 3-2; then remove the oil inlet pipe from the fuel distribution pipe, connect the VAG1318 fuel pressure gauge to the inlet end, and the other end of the fuel gauge with an auxiliary tubing into a cup, Pressure gauge valve opening degree, to maintain the pressure gauge reading 3MPa, running oil pump 30s, observe the cup of fuel capacity, fuel pump oil consumption of 610mL, greater than the rated oil supply 580ml / 30s requirements; continue to use VAG1715 digital Multimeter measurement of the current clip caught in the fuel tank outside the fuel pump power supply line, measured fuel pump current is less than 6.5A, indicating that the electronic fuel pump is working properly.
    In order to determine whether the ignition system for the reasons, the main cylinder line, sub-cylinder line, distributor cover and sub-head with a multimeter to check the resistance value. The main cylinder line resistance requirements 0 ~ 2.81kΩ, sub-line line 0.6-7.4kΩ, sub-head 1 ± 0.4kΩ, check the result is the main cylinder line resistance of 1kΩ, sub-cylinder line in the 5kΩ or so, sub-head for the 2kΩ, no Found abnormal.
    Then take the following measures: ① replace the engine control unit ECU. ② replace the throttle potentiometer. ③ Replace the idle stabilizer valve. ④ Replace the intake air temperature and intake pressure sensor. ⑤ Replace the oil pressure regulator. ⑤ replace the engine control harness, the results of the above programs are invalid, also ruled out the possibility of damage to these components.
    Again test 39km did not find abnormal, but parked a noon, only 5km old hospital relapse. And listen to the sound like a leak, but also because the car repeatedly flameout, it is suspected that the engine vacuum system leak, but check the vacuum pipe and other parts are not unusual. At this point began to consider the power supply system power supply problems, and the use of equipment to observe the power supply voltage, but did not find abnormal. So the temporary replacement of another car in the repair of the generator, test all 70km normal.