- an air pipe between the turbocharger and the air filter, as well as a pipe between the air filter and the injection pump. The nozzles may be leaking, or their fastening has loosened;
- air can enter the engine between the air filter and the block head;
- the air filter mounting flange may be leaky;
- it is also possible that there is a leak between the exhaust manifold and the block head or between the manifold and the turbocharger.
A special device is used to check the boost pressure, so this work must be carried out at a service station. If the pressure is too high and the connection to the boost pressure regulator is not clogged, the turbocharger most likely needs to be replaced.
The bypass valve may also be the cause of the malfunction, then the boost pressure becomes below normal.
The malfunction, the elimination of which will cost the most, is associated with the failure of the balanced fuel supply system, which is located in the high-pressure fuel pump. If the synchronization device is faulty, the injection pump must be replaced. If the color of the exhaust has changed, there may be a malfunction in the injection system, so it needs to be diagnosed as soon as possible.