TM 5-3805-291-23-1
TURBOCHARGER ASSEMBLY, AIR LINES, AND OIL LINES REPLACEMENT - CONTINUED
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CLEANING AND INSPECTION - CONTINUED
Wastegate Inspection
C AU T I O N
Damage will result when increased heat and/or friction due to higher engine output goes beyond engine
cooling and lubrication system's abilities. Boost pressure controls maximum rpm of turbocharger, because
boost pressure controls position of wastegate.
N OT E
Wastegate controls amount of exhaust gas that is alowed to bypass turbine side of turbocharger. This
l
valve then controls rpm of turbocharger. When engine operates in conditions of low boost (lug), a
spring presses against a diaphragm in canister. Actuating rod will move and diaphragm in canister
wastegate will close. Then, turbocharger can operate at maximum performance. When boost pressure
increases against diaphragm in canister, wastegate will open. Rpm of turbocharger becomes limited.
Rpm limitation occurs because a portion of exhaust gases bypass turbine wheel of turbocharger.
Boost pressures that are too high at full load condtions and too low at all lug conditions indicate a pos-
i
sible problem with wastegate, wastegate solenoid, and air lines.
Housing assembly for wastegate is presetat factory and no adjustments can be made.
The following factors also affect maximum rpm of turbocharger:
Engine rating
Horsepower demand on engine
High idle rpm
Height above sea level for engine operation
Inlet air restriction
Exhaust system restriction
Inspect for broken or missing parts and free movement.
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