Introduction (Turbocharger): Notes

For charged engines, exhaust turbochargers are of significant importance to the power development. The turbochargers deliver the charging pressure that is required by the engines. Depending on the system (one-phase or multi-phase), one or more turbochargers are installed. However, the function of the turbocharger greatly depends on the proper function of other components in the periphery.

This information describes the sources of fault on the actual exhaust turbocharger as well as the factors influencing and causing faults in the periphery.

The following pictures show examples for the schematic structure of one-phase or multi-phase systems with the subsequently required actuators.

Fig 1: Exhaust Turbochargers One-Phase System Diagram

Courtesy of BMW OF NORTH AMERICA, INC.

One-phase system 

Fig 2: Exhaust Turbochargers Two-Phase System Diagram

Courtesy of BMW OF NORTH AMERICA, INC.

Two-phase system 

Fig 3: Sectional View Of Turbocharger

Courtesy of BMW OF NORTH AMERICA, INC.

Sectional view of turbocharger 

General notes on troubleshooting 

The following notes must be observed in order to find the root cause of faults when problems are reported, and to prevent the unauthorized, i.e. inappropriate, replacement of the exhaust turbocharger:

1. Tracking down and verifying the complaint 

   If possible, any problem reported ('complaint') should be tracked down and verified on the vehicle. The parameters or marginal conditions prevailing at the time the problem was reported need to be noted down.

2. Diagnosis 

   As a first procedural step, diagnosis must  be performed using the diagnosis system.

   Faults on sensors and actuators may be responsible for 'complaints', i.e. reported problems, which may also be associated with the exhaust turbocharger in some way. For this reason, faults on sensors and actuators must  first be remedied if these are stored in the fault memory.

   In addition, the engine ventilation is important for the oil supply to the exhaust turbocharger. If the pressure in the crankcase is too high, the oil supply to the exhaust turbocharger is endangered, and oil leakage may occur at the exhaust turbocharger.

   After that, the charge pressure faults saved must be investigated, or troubleshooting must take place on the exhaust turbocharger.

3. Repair history 

   If possible, check to find out whether repairs have already been made on or near the exhaust turbocharger following similar reported problems.

   • With any repeated complaint with different fault patterns, the problem could have arisen during the last repair. Problems could have arisen in conjunction with installation, connections or the ingress of foreign bodies.
   • In the event of identical complaints, it is highly probable that the actual cause of the fault has not been remedied.