Common faults and treatment methods of VVT solenoid valve
Date: 2020-06-10 09:03:22 Clicks: 204
一、Common faults of VVT electronic valve
Most of the faulty parts of the VVT system are the oil control solenoid valve, and the failure of the oil control solenoid valve is almost always the moving spool (1) stuck.
二、Fault range with difficult starting (engine rotates normally)
Spark plug, ignition coil failure; leakage of high-voltage wire, loose or disconnected wire connection.
②Oil circuit failure
The fuel pipe (including hose) is dirty or clogged, and the fuel pump is faulty (check the fuel pressure).
③Electronic control part
Electronic throttle body assembly failure or APP sensor failure, ECT sensor or MAF sensor failure, ECM failure, camshaft position control system failure.
Low cylinder pressure (poorly tightened spark plug or gasket failure); pressure leakage on valve seat, sticky stem, insufficient or damaged valve spring force; cylinder head gasket leakage, sticky or damaged piston ring, piston, ring or cylinder Wear; PCV valve failure, air intake from the intake manifold pad or throttle body pad.
三、Unsteady engine idling fault range (no idling engine)
Circuit failure Spark plug failure, high-voltage line leakage or high-voltage line disconnection, point coil with igniter failure.
The fuel pressure exceeds the limit, the fuel injector malfunctions, and the evaporative emission control system malfunctions.
Electronic control part failure
Poor sensor performance, electronic throttle body assembly failure (too much carbon deposit, dirty, etc.), sensor failure, electrical load component failure (headlights, blower and rear defrost), idle air control failure, generator and line failure, )system error
Intake manifold, throttle valve body or cylinder head gasket leakage evaporative emission control system failure, engine overheat, low cylinder pressure, loose or disconnected vacuum hose connection, valve failure (some models need to consider the EGR valve is not closed tightly).
四、Causes of difficulty in starting and unstable idling due to malfunction of the oil control solenoid valve
When the engine is started and stopped, the position of the oil control solenoid valve should be at the maximum delay (in order to prevent the exhaust gas from flowing back to the intake manifold, the overlap of the valve openings should be shortened to improve the starting ability).
When the engine is idling, the position of the oil control solenoid valve should also be at the maximum delay (in order to prevent the exhaust gas from flowing back to the intake manifold, the overlap of the valve openings should be shortened to stabilize the engine idling speed).
If foreign objects (metal particles, sludge and other impurities) in the oil circuit enter the oil control solenoid valve, the moving spool will be stuck in the advanced position. In this case, when the vehicle is started, due to the reverse flow of exhaust gas and insufficient air intake, it will cause difficulty in starting or unstable idle speed.
Fifth, the failure of the oil control solenoid valve leads to difficulty in starting and the treatment of unstable idle speed
When you can't start, you can step on the throttle, and you can basically start the vehicle (it is generally difficult to start without stepping on the throttle, and the idle jitter is very large after starting.)
Vibration oil control valve can be knocked on the car (slight stuck can be solved).
Disassembly, inspection, cleaning and maintenance.
Replace the oil control solenoid valve (resistance check does not match and the fault cannot be eliminated after cleaning)
2、Cleaning (After cleaning, lubricate with engine oil, and apply power for about 5 times, observe whether the movement of the sliding spool is normal. Practice has proved that diesel is better than the cleaner.
七、 Inspection of oil control solenoid valve