Pontiac Fiero 1988 Service Manual page 54

AIR CONDITIONING 1B-9
V - 5 S Y S T E M A I R C O N D I T I O N I N G D I A G N O S I S
I N S U F F I C I E N T C O O L I N G " C H A R T B "
INSTALL HIGH AND LOW PRESSURE GAGES.
BOTH GAGES READ WITHIN 70 kPa (10 PSI) OF EACH OTHER.
DISCHARGE SYSTEM. REMOVE COMPRESSOR CONTROL VALVE
AND INSPECT O-RINGS. IF O-RINGS ARE DAMAGED, REPLACE
O-RINGS AND REINSTALL CONTROL VALVE. IF O-RINGS
ARE OK, REPLACE THE CONTROL VALVE ASSEMBLY.
1
GAGES SHOW A
GREATER THAN
70 kPa (10 PSI)
DIFFERENTIAL.
EVACUATE AND CHARGE
OK
CHECK TEMPERATURE DOOR ADJUSTMENT TO VERIFY
DOOR IS SEALING IN THE FULL COLD POSITION.
IF PROBLEM RESISTS
REPLACE COMPRESSOR
PUMP ASSEMBLY
DOOR OK
OK
ADJUST TEMPERATURE
CABLE TO SEAL DOOR
FULL COLD.
FEEL LIQUID LINE BEFORE EXPANSION TUBE. IMPORTANT!
VEHICLES ARE EQUIPPED WITH AN ORIFICE TUBE
LOCATED IN THE LIQUID LINE. SEE
ILLUSTRATIONS FOR SPECIFIC LOCATION.
WARM
LEAK CHECK SYSTEM.
NO LEAK FOUND.
LEAK F
DISCHARG
: OUND.
E SYSTEM.
REPAIR ANY LEAK FOUND.
DISCHARGE
SYSTEM.
REMOVE ORIFICE AND EXAMINE.
NO ORIFICE.
ZZZUZZ
HEAVILY RESTRICTED.
INSTALL NEW
ORIFICE,
EVACUATE
AND CHARGE.
REPLACE COMPRESSOR PUMP
ASSEMBLY. INSTALL NEW
ORIFICE. EVACUATE
AND CHARGE.
OK
OK
OK
COLD
RESTRICTION IN THE HIGH
SIDE OF THE SYSTEM. VISUAL-
LY CHECK FOR FROST SPOT TO
LOCATE THE RESTRICTION.
REPAIR AS REQUIRED.
EVACUATE AND CHARGE
OK
1
CLEAN OR SLIGHTLY RESTRICT-
ED ORIFICE SCREEN (A
SMALL AMOUNT OF METALLIC
CHIPS ARE NORMAL).
CLEAN AND REINSTALL ORIFICE
EVACUATE AND CHARGE.
IF POOR COOLING CONTINUES SEE CHART D.
JL
OK
H 2 0 0 0 8 I B
higure 8 V-5 A/C System Insufficient Cooling Diagnostic Procedure (2 of 4)