Troubleshooting - Toyota Supra 1990 Manual

TURBOCHARGER SYSTEM - Troubleshooting TC-S
TROUBLESHOOTING
HINT: Before troubleshooting the turbocharger, first check
the engine itself. (Valve clearance, engine compression,
ignition timing etc.)
INSUFFICIENT ACCELERATION, LACK OF POWER OR
EXCESSIVE FUEL CONSUMPTION
(Possible Cause)
1. TURBOCHARGING PRESSURE TOO
-
LOW
2. RESTRICTED INTAKE AIR SYSTEM
3. LEAK IN INTAKE AIR SYSTEM
4. RESTRICTED EXHAUST SYSTEM
5. LEAK IN EXHAUST SYSTEM
6.
ERRATIC TURBOCHARGER
OPERATION
t - -
(Check Procedure and Correction Method)
Check turbocharging pressure. (See page TC-8)
Turbocharging pressure:
M/T 0.39 - 0.S3 kg/cm2
(S.S - 7.5 psi, 38 - 52 kPa)
A/T
0.34 - 0.42 kg/cm 2
(4.8 - 6.0 psi, 33 - 41 kPa)
If the pressure is below specification, begin
diagnosis from item 2.
Check intake air system, and repair or replace parts
as necessary. (See page TC-7)
Check intake air system, and repair or replace parts
as necessary. (See page TC-7)
Check exhaust system, and repair or replace parts as
necessary. (See page TC-7)
Check exhaust system, and repair or replace parts as
necessary. (See page TC-7)
Check rotation of impeller wheel. If it does not turn
or turns with a heavy drag, replace the turbocharger
assembly.
Check plays of turbine shaft. (See page TC-14)
Axial play: 0.13 mm (0.0051 in.) or less
Radial play: 0.18 mm (0.0071 in.) or less
If not within specification, replace the turbocharger
assembly.