Mitsubishi 3000GT 1991, Service Manual

Page: 1099 / 1146

HEATERS AND MANUAL AIR
Service Adjustment Procedures
ADJUSTMENT PROCEDURES
(1) Select a quiet area for testing. Duplicate conditions as much
as possible. Switch compressor on and off several times to
clearly identify compressor noise.
To duplicate high ambient conditions (high head pressure),
restrict air flow through condenser. Install manifold gauge
set to make sure discharge pressure doesn’t exceed 2,070
(300 psi).
(2) Tighten all compressor mounting bolts, clutch mounting
bolt, and compressor drive belt. Check to assure clutch coil
is tight (no rotation or wobble).
(3) Check refrigerant hoses for rubbing or interference that can
cause unusual noises.
(4) Check refrigerant charge. (See “Charging System”.)
(5) Recheck compressor noise as in Step 1.
(6) If noise still exists, loosen compressor mounting bolts and
retorque. Repeat Step 1.
(7) If noise continues, replace compressor and repeat Step 1.
POWER RELAY CHECK
(1) Remove the radiator fan motor relays (HI) and (LO) from the
relay box on the right of the engine compartment.
(2) Remove the radiator fan motor relay (air conditioner),
condenser fan motor relays (HI) and (LO), and
conditioner compressor relay from the relay box on the left
of the engine compartment.
(3) Remove the blower motor relay from the junction box.
(4) Remove the blower motor HI relay from the blower case
assembly.
(5) Check the continuity between terminals using a circuit
tester.
Blower HI relay
IDLE-UP OPERATION CHECK
Before inspection and adjustment set vehicle in the
following condition:
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Engine coolant temperature: 80 95°C (176 203°F)
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Lights, electric cooling fan and accessories: Set to OFF
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Transaxle: Neutral (N or P for vehicles with
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Steering wheel: Straightforward
(2) Check to be sure that the idling speed becomes the
standard value when the air conditioner switch is switched
ON and the air conditioner is activated.
Standard value: 900 100 rpm
NOTE
There is no necessity to make an adjustment, because the
idling speed is automatically adjusted by the system.
If, however, there occurs a deviation from the standard
value for some reason, check the system.
ISC: Idle Speed Control
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