Turbocharger Troubleshooting; Manifold Pressure Low Or Fluctuating; Aircraft Cannot Reach Critical Altitude - Piper PA-44-180 SEMINOLE Maintenance Manual

GENERAL.
DESCRIPTION AND OPERATION.
The turbocharger system (Figure 81-1) consists of a turbine and compressor assembly, ground adjustable
exhaust bypass screw and the necessary hose and engine air intake ducts. The ground adjustable exhaust bypass
screw allows some exhaust gas to bypass the turbine and flow directly overboard. The turbocharger requires little
attention between overhauls. However, it is recommended that the items outlined in the Inspection Report be
checked periodically.
— CAUTION —
EXTREME CARE SHOULD BE EXERCISED AT ALL TIMES WHILE
S E RVICING OPERATING TURBOCHARGERS. KEEP FINGERS AND
FOREIGN OBJECTS AWAY FROM OPENINGS. AVOID CONTACT WITH
HOT SURFACES.
O P E R ATION OF THE ENGINE AT ANY SPEED FASTER THAN IDLE
IMMEDIATELY AFTER START-UP CAN RESULT IN "OIL LAG" FAILURE
OF TURBOCHARGER BEARINGS, ESPECIALLY IN COLD WEATHER OR
AFTER A PROLONGED NON-OPERATIVE PERIOD.
TROUBLESHOOTING.
CHART 8101. TROUBLESHOOTING (TURBOCHARGER)
Trouble
Manifold pressure low or
fluctuating.
Aircraft cannot reach critical
altitude.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
Cause
Restriction in duct between air
cleaner and turbocharger.
Restriction in duct between
compressor and engine intake
manifold .
Restriction in engine exhaust
system after turbocharger.
Restriction in engine intake or
exhaust manifold.
Pressure relief valve opens at too
low of a pressure.
3J3
Remedy
Remove restriction.
Remove restriction.
Remove restriction.
Refer to appropriate engine
manufacturers maintenance
manual.
Recalibrate or replace relief
valve.
Page 81-01
Revised: May 15, 1989
8 1 - 0 2 - 0 0