[Vehicle information]]
Car model: magotan 1.8T
Fault: an accident occurred while the vehicle was running. The oil pan and the oil pump were damaged due to the collision between the oil pan after the chassis bottom supporting and road obstacles. After the oil pan of the oil pump was replaced, the engine was difficult to start and the engine was shaking seriously after starting.
[Fault analysis and maintenance process]]
1. Use VAS5052A to detect the following faults, which can be cleared after flameout and cannot be cleared after startup.
2. Read data streams
When idling, the pulse duty ratio of the intake camshaft of the normal car and the faulty car is quite different, the normal car is 5.9%, and the faulty parking space is 47.5%; When accelerating, the state of the camshaft adjusting device of the normal car changes with the engine speed, however, the faulty car does not change due to entering the emergency mode. The fault code is cleared after flameout, which changes, but the numerical value is quite different from the normal value.
3. It is judged that the fault point is timing mark wrong. The factors affecting timing mark wrong are as follows:
Camshaft adjusting device failure (cause: abnormal operation of N205 solenoid valve; Mechanical failure of camshaft adjusting control valve; Insufficient oil pressure, etc.)
The chain mark is incorrect. An error occurs due to collision or installation.
4. Perform component diagnosis check that the N205 solenoid valve works normally, check that the Camshaft adjustment control valve has no hairpin phenomenon, and replace the above two components with other vehicles for testing, and the fault is still the same.
5. Check the oil pressure. The engine temperature is above 80 degrees and the oil pressure is 2.8bar, which is normal.
6. Disassemble the timing chain and check that crankshaft timing sprocket and crankshaft marks are wrong.
7. Replace the timing sprocket, reinstall the timing part, and troubleshoot.
Cause analysis: due to incorrect timing sprocket position, the chain mark is wrong, and CMP camshaft position sensor and motor speed sensor placement error codes appear.
Fault handling method: replace the timing sprocket and install the timing chain for troubleshooting.
