Turbocharger system diagram
- 1 activated carbon adsorber
- 2 ventilation pipe from the fuel tank
- 3 check valve for activated carbon adsorber
- 4 exhaust gas driven turbocharger
- 5 fuel pressure regulator
- 6 intake manifold (fuel line)
- 7 crankcase ventilation
- 8 activated carbon adsorber check valve
- 9 connection on the throttle body
- 10 intercooler (charge air cooler)
- 11 intercooler receiver
- 12 coasting cut-off valve
- 13 electromagnetic valve for limiting boost pressure
- 14 crankcase ventilation pressure limiting valve
- 15 Electrically controlled adsorber valve
To avoid damage to the oxygen sensor and catalytic converter, the following requirements must be met:
Petrol engines
- Be sure to use only unleaded gasoline.
- Starting a warmed-up petrol engine by pushing or towing is permitted only in one attempt and at a distance of no more than 50 m. It is better to use a jumper cable for this purpose. Unburned fuel during ignition can lead to overheating of the catalytic converter and its destruction.
Warning: Starting vehicles with automatic transmission is not possible for technical reasons.
- If you have difficulty starting the engine, do not engage the starter for too long. This will cause continuous fuel injection. It is necessary to identify and eliminate the cause of the malfunction.
- If there are problems with the ignition system, when determining their nature, it is necessary to exclude fuel injection when the starter is turned on. To do this, disconnect the fuel pump relay.
- Never empty the fuel tank completely.
- If misfiring occurs, do not increase engine speed and correct the problem immediately.
- Use only recommended spark plugs.
- Do not perform spark testing with the spark plug connector disconnected.
- It is not allowed to test the operation of the cylinder by disconnecting the spark plug wire from its spark plug. This will cause unburned fuel to enter the catalytic converter.
- Do not park the vehicle over dry leaves or grass. The exhaust system in the area of the catalytic converter is very hot and radiates heat even after the engine has stopped.
- Do not apply underbody protection products to exhaust system components.
- It is not permitted to change the design of heat shields.
- When filling the engine with oil, pay special attention to never exceeding the level indicated on the indicator as Max. Excess oil due to incomplete combustion enters the catalytic converter and can damage its alloy metal coating or completely destroy the catalytic converter.
Turbocharger
Petrol engines 1.8 l 150 hp. equipped with a turbocharger.
The turbocharger has two turbines mounted on one shaft and housed in two separate housings: a drive turbine powered by exhaust gases and a booster turbine that compresses the air entering the engine. The angular speed of the turbine shaft reaches 120,000 rpm. The turbocharger is lubricated by the engine lubrication system. Additionally, the turbocharger is cooled by the engine cooling system fluid.
The increase in engine power due to turbocharging reaches 100%. The increase in power depends, among other things, on the pressure of the supplied air, which in passenger car engines is 0.4 – 0.8 bar (the air pressure in the tires is 1.8 bar). The air pressure is monitored by a sensor. If the air pressure exceeds the set value, the pressure control valve opens, reducing it.
Along with the increase in power due to the use of a turbocharger, the torque also increases, which primarily affects the improvement of the engine's elasticity. The condition for reliable supercharging is the rotation of the turbocharger at the required speed. Therefore, the engine has a relatively small turbocharger, which begins to work already at low engine speeds, and increases its torque.
Between the turbocharger and the engine intake tract there is an intercooler (supply air cooler). Cooling the air helps to increase engine power, since cold air, due to its higher density, has a higher oxygen content.
The diesel engine has an adjustable turbocharger (variable geometry turbocharger) provides an increase in engine power. Smooth adjustment of the blades is carried out by the engine control system via an electromagnetic valve and a vacuum box. Thanks to this, at any speed, optimal boost pressure is achieved and thus an increase in engine power, in particular at low engine speeds.
The turbocharger is a precision mechanism. Therefore, in the event of a malfunction, the turbocharger should generally be replaced.
Turbocharger malfunctions
If the turbocharger is not working properly, this can be determined by a decrease in power or the inability to reach maximum speed, assuming that the fuel injection system is working properly. This can be caused by a leak in the system or a faulty turbocharger. The following sequence of checks is recommended:
Leaks in the system
Check the air hose between the turbocharger and the intake manifold through the intercooler for kinks, cracks, loose connections, etc. and repair them if found. Check for leaks between the cylinder head and the intake manifold. This can be caused by faulty gaskets or, in some cases, by the displacement of the manifold.
Leaks may be in the connecting flanges between the exhaust manifold and the cylinder head or between the exhaust manifold and the turbocharger.
Faulty turbocharger
Have the boost pressure checked at a workshop. It may be too high or too low. If the pressure is too high, the reason may be a faulty boost pressure limiting solenoid valve or a faulty boost pressure control valve receiver. A workshop diagnostic memory scan will help determine where the fault is.
If the pressure is too low, then the boost pressure limiting device receiver can be suspected. Otherwise, the turbocharger must be faulty.
Removal and installation a turbocharger
As you know, the engine should not be turned off immediately after a long trip at high speed, it is necessary to let it idle for a while. The reason for this is as follows: if you immediately turn off an "overheated" engine, the turbocharger shaft bearing will heat up so much that the oil for lubricating the bearing may burn out. With such treatment and repeated start-up, the turbocharger will soon fail.
The turbocharger is quite sensitive to dirt or foreign objects, so cleanliness must be maintained during removal and installation.
1. Disconnect the ground wire from the battery (don't forget about the radio receiver coding).
2. Remove the air hose from the turbocharger.
3. Clamp the coolant hose going to the turbocharger with a clamp or drain the coolant.
4. Raise and support the front of the vehicle on stands.
5. Disconnect the exhaust system mount from the manual transmission. Disconnect the catalytic converter from the turbocharger (4 nuts). Disconnect the supply and return oil pipes from the turbocharger. Make sure that as little oil as possible flows out. From the bottom, unscrew the bolts securing the turbocharger to the exhaust manifold. These bolts are not easy to reach, so you need to use a suitable wrench (12mm open-end wrench). Hold the turbocharger while doing this and when all the bolts are removed, pull it up. Installation is done in the reverse order of removal. Always use new nuts and bolts. Before connecting the oil supply pipe, pour some oil into the turbocharger (pre-lubrication). At first, do not let the engine run at high speed.
The article is a reprint of material from: AudiManual.ru