Turbocharger: Testing and Inspection
CHECKING BOOST PRESSURE OF TURBOCHARGERTest value
Boost pressure at full-load, driving range position "L" or "S" and n = 4000 rpm: 0.7-0.8 bar gauge pressure
Special tool
Conventional tester
Digital tester (or revolution counter installed in vehicle) e.g. Bosch, MOT 001.03
Checking
A. On boost air pipe
Connect boost pressure tester to intake manifold, unscrewing plug for this purpose.
Note: Tester connecting thread M 10 x 1.
B. On switchover valve
Connect boost air tester to switchover valve with Y-distributor, output of switchover valve.
1. Test on dynamometer.
Drive vehicle in driving range "S" at full-load and n = 4000 rpm. The prescribed boost pressure must be obtained.
Check the troubleshooting hints if system fails to reach specified boost pressure.
2. Road test.
Note: The full-load test must be kept as short as possible because the total driving energy has to be absorbed by the vehicle's own brakes.
Road-test the vehicle in driving range "L" or "S" at full-load and n = 4000 rpm, placing tester in vehicle interior for this purpose. Accelerate to full throttle while holding at 4000 rpm with the aid of service brakes (No. 2 in illustration). The prescribed boost pressure must be reached.
Check the trouble-shooting hints if system fails to reach specified boost pressure.
