Piper Navajo PA-31 Service Manual page 525

PIPER NAVAJO SERVICE MANUAL
TABLE VIII-II. TROUBLESHOOTING
CHART (TURBOCHARGER) (cont.)
Trouble
Cause
Remedy
Engine surges or smokes.
(cont.)
Bootstrapping.
Operate engine within range
outlined in operation manual.
NOTE
Smoke would be normal if engine has idled for a prolonged period.
High deck pressure. (Com-
pressor discharge pressure.)
Controller metering valve not
opening. Aneroid bellows
leaking.
Replace controller assembly
or replace aneroid bellows.
Wastegate sticking closed.
Controller return line
restricted.
Oil pressure too high.
Wastegate controller mal-
function.
Wastegate actuator piston
locked in full closed position.
(Usually accompanied by oil
leakage at actuator drain line.)
NOTE: Wastegate normally
closed in idle and low power
conditions. Should open when
actuator inlet line is dis-
connected.
Shut-off valve in return line
not working. Butterfly shaft
binding. Check bearings.
Replace by-pass valve or
correct linkage binding.
Clean or replace line.
Check pressure 75 to 85 psi
(80 psi desired) at wastegate
actuator inlet. If pressure on
outlet side of actuator is too
high, have wastegate con-
troller adjusted.
Replace controller.
Remove and disassemble
actuator, check condition of
piston and packing or replace
actuator assembly.
Manifold pressure drops as
altitude increases. (below
1500 feet.)
Malfunction of pressure ratio
controller.
Replace pressure ratio con-
troller.
Reissued: 10/12/79
POWER PLANT
2K3