Air Intake and Exhaust System Operation and Tests
IMPORTANT: On some vehicles, it may not be
possible to meet the turbo boost
pressure due to inability to get full load
rated speed. In these cases, see
machine operation and test manual for
the appropriate test method and
3. Observe pressure reading on gauge. Boost pressure
should be within ranges shown in charts on following
pages when engine is developing rated power at full
load rated speed.
4. If boost pressure is too high, remove fuel injection
pump and have it checked for high fuel delivery by an
authorized diesel repair station.
If boost pressure is too low, check the following:
Restricted air filter elements.
Restricted fuel filter elements.
Incorrect fast idle adjustment.
Incorrect injection pump timing.
Exhaust manifold leaks.
Intake manifold leaks.
Faulty fuel transfer pump.
Low compression pressure.
Faulty fuel injection nozzles.
Carbon build-up in turbocharger.
Low fuel injection pump fuel delivery.
5. After completing test, remove test equipment and
reinstall nozzle adapter and plug. Tighten securely.