stop start FORD FESTIVA 1991 Service Manual

Fig. 2: Moving Quadrant on Drum Brake Adjuster (Festiva)

Courtesy of FORD MOTOR CO.
FRONT AXLE BEARINGS
Front bearing preload is adjusted during bearing replacement by changing preload spacer. See FRONT WHEEL BEARINGS under
REMOVAL & INSTALLATION.
REAR AXLE BEARINGS
With bearings installed, tighten NEW lock nut to 18-22 ft. lbs. (24-30 N.m) while rotating wheel. Slightly loosen lock nut so it can be turned
by hand. Install a lug nut into axle hub. Attach an inch-pound torque wrench to lug nut at 12 o'clock position. Measure bearing preload.
Tighten lock nut until bearing preload, including seal drag, is 3.5-6.2 INCH lbs. (.4-.7 N.m). Stake NEW lock nut into notch on spindle.
TESTING
POWER BRAKE UNIT
Functional Test
1. Check master cylinder fluid level and hydraulic system for leaks. Place transaxle in Neutral or Park, turn ignition off and apply parking
brake. Pump brake pedal several times to eliminate vacuum from system, and hold pedal in depressed position.
2. Start and idle engine. If vacuum system is functioning properly, pedal moves downward under constant foot pressure. If no pedal motion
is felt, vacuum booster is not functioning properly. Go to next step.
3. Run engine for at least one minute and turn ignition off. Depress brake pedal several times. Booster is okay if pedal stroke is long at first
and becomes shorter with each stroke. If stroke does not shorten, check for a damaged, restricted or improperly connected check va l ve
vacuum hose. Repair and recheck. Go to next step.
4. Restart engine. Depress and hold pedal down. Turn ignition off and wait 30 seconds. Booster is okay if pedal height remains unchanged.
If pedal height changes, check for a damaged, restricted or improperly connected check valve or vacuum hose. Go to next step.
5. Connect a pressure gauge to master cylinder output line. Connect a vacuum gauge to booster and a pedal depression force gauge to
brake pedal. Bleed air from pressure gauge. Start engine. When vacuum gauge reads 19.7 in. Hg, turn ignition off. Watch vacuum ga u ge
for 15 seconds. Booster is okay if vacuum gauge reads 18.7-19.7 in. Hg. If vacuum gauge reads less than 18.7 in. Hg, proceed to next
step.
6. Restart engine. Apply and hold 44 lbs. (196 N) force to brake pedal. When vacuum gauge reading reaches 19.7 in. Hg, turn ignition off.
Watch vacuum gauge for 15 seconds. Booster is okay if vacuum gauge reads 18.7-19.7 in. Hg. If vacuum gauge reads less than 18.7 in.
Hg, proceed to next step.
7. With engine stopped and vacuum gauge at zero, check pressure gauge. Apply 44 lbs. (196 N) force to brake pedal and check pressure
gauge. Booster is okay if pressure gauge reads 256 psi (18 kg/cm
2 ).
8. Remove pedal force and start engine. When vacuum gauge reaches 19.7 in. Hg, apply 44 lbs. (196 N) force to pedal. Booster is okay if
pressure gauge read 768 psi (54 kg/cm
2 ).
Diagnosis
If booster does not function properly, see Fig. 3 .
NOTE:Axle lock nut on right side has left-hand threads. Always install NEW lock nut when rem oved.
NOTE:Inspect all vacuum hoses for holes, collapsed areas and secure connections. Ensure all unused
vacuum ports are capped.
Page 3 of 12 MITCHELL 1 ARTICLE - BRAKE SYSTEM 1991-92 BRAKES Disc & Drum
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CATALYTIC CONVERTER
Continued operation of vehicle with a severe malfunction could cause converter to overheat, resulting in possible damage to converter and
ve h ic l e .
Any modification to the exhaust system on turbo models, which reduces exhaust backpressure, will lead to lean fuel mixtures and excessive
spark advance. This could cause serious engine damage.
ELECTROSTATIC DISCHARGE SENSITIVE (ESD) PARTS
ENGINE OIL
FUEL PUMP SHUTOFF SWITCH
This switch stops flow of fuel to engine after a collision. The impact does not have to be great for switch to be triggered. Switch must be reset
after collision. Switch is located under left rear speaker in luggage compartment. Press button to reset switch.
FUEL SYSTEM SERVICE
HALOGEN BULBS
PASSIVE RESTRAINTS
RADIATOR CAP
RADIATOR FAN WARNING:Many solid state electrical com ponents can be dam aged by static electricity (ESD). Som e will display a
warning label, but m any will not. Discharge personal static electricity by touching a m etal ground point
on the vehicle prior to servicing any ESD sensitive com ponent.
CAUT ION: Never use non-detergent or straight m ineral oil.
WARNING:Relieve fuel system pressure prior to servicing any fuel system com ponent (fuel injection m odels).
WARNING:Halogen bulbs contain pressurized gas which m ay explode if overheated. DO NOT touch glass portion
of bulb with bare hands. Eye protection should be worn when handling or working around halogen
bulbs.
CAUT ION: Before operating vehicle, securely fasten passive shoulder restraints to the em ergency release buckles.
T he buckle fits in only one way. Ensure to position it properly.
CAUT ION: Always disconnect the fan m otor when working near the radiator fan. T he fan is tem perature controlled
and could start at any tim e even when the ignition key is in the OFF position. DO NOT loosen or rem ove
radiator cap when cooling system is hot.
WARNING:Keep hands away from radiator fan. Fan is controlled by a therm ostatic switch which m ay com e on or
run for up to 15 m inutes even after engine is turned off.
Copyr ight 2009 Mitchell Repair Information Company, LLC. All Rights Reserved.
Article GUID: A00058075
Page 3 of 3 MITCHELL 1 ARTICLE - FUSES & CIRCUIT BREAKERS Fuses & Circuit Breakers 1988-93 Festiva
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Shift Lock ActuatorShift Interlock Systems
Side Marker LightsExterior Lights
SIR Coil Assembly (Clockspring)Air Bag Restraint System
Slip Ring (Clockspring)Air Bag Restraint System; Steering Column Switches
SRS Control ModuleAir Bag Restraint System
Starter MotorStarters
Starter Interrupt RelayStarters
Starter SolenoidStarters
Starter RelayStarters
Steering Wheel Position SensorAnti-Lock Brakes
StoplightsExterior Lights
Stoplight SwitchEngine Performance; Cruise Control Systems; Anti-Lock Brakes
Sun Roof ECUPower Sun Roof
Sun Roof MotorPower Sun Roof
Sun Roof Position SensorPower Sun Roof
TaillightsExterior Lights
Throttle Position (TP) SensorEngine Performance
Torque Converter Clutch Solenoid/SwitchEngine Performance
Traction Control SwitchAnti-Lock Brakes
Trailer Tow ConnectorExterior Lights
Trailer Tow RelayExterior Lights
Transmission/TransaxleEngine Performance
Transmission Control Module (TCM)Engine Performance; Starters
Transmission Range SensorStarters; Back-Up Lights; Engine Performance
Transmission Range SwitchBack-Up Lights; Engine Performance; Anti-Theft System
Turn Signal FlasherExterior Lights
Tu r n S ign a l Ligh t sExterior Lights
Twilight Sentinel SwitchHeadlight Systems; Daytime Running Lights
Vapor Canister Leak Detection PumpEngine Performance
Vehicle Control Module (VCM)Engine Performance
Vehicle Dynamic ModuleElectronic Suspension
Vehicle Speed Control ServoCruise Control Systems
Vehicle Speed SensorData Link Connectors; Analog Instrument Panels; Cruise Control
Systems; Electronic Suspension
Voltage RegulatorGenerators & Regulators
Water-In-Fuel SensorEngine Performance; Analog Instrument Panels
Wheel Speed SensorsAnti-Lock Brakes
Window Timer ModulePower Convertible Top
Windshield Intermittent Wiper RelayWiper/Washer Systems
Windshield Washer MotorWiper/Washer Systems
Wiper MotorWiper/Washer Systems
Copyr ight 2009 Mitchell Repair Information Company, LLC. All Rights Reserved.
Article GUID: A00130983
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WIRING DIAGRAMS
1991 WIRING DIAGRAMS Ford Motor Co.
IDENTIFICATION
COMPONENT LOCATION MENU
COMPONENT LOCATIONS
WIRING DIAGRAMS
ComponentFigure No. (Location)
A/C RELAY3 (B 8)
A/T SELECT LIGHT3 (E 8)
ALTERNATOR1 (C 3)
BACK-UP LIGHT SWITCH5 (D 19)
BATTERY1 (A 2)
BLOWER SWITCH3 (C 9)
BRAKE WARNING SWITCH1 (C 2)
CIG LTR4 (E 14)
CLUTCH INTERLOCK SWITCH (M/T)1 (B 2)
CONDENSER FAN (A/T)3 (C 8)
COOLANT FAN MOTOR1 (D 3)
COOLANT FAN RELAY1 (D 3)
DEFOG SWITCH5 (C 16)
DIR/HAZARD SWITCH4 (B-C 12)
ELECT CONTROL ASSY (ECA)2 (A 4-7)
FRONT WASHER MOTOR1 (E 3)
FRONT WIPER MOTOR1 (E 3)
FRONT WIPER/WASHER SWITCH5 (A 16)
FUEL PUMP INERTIA SWITCH2 (D 4)
FUEL PUMP RELAY2 (C 4)
FUSE BLOCK3 (D-E 9-10)
HEADLIGHT RELAY4 (D 14)
HORN RELAY3 (E 11)
HORN SWITCH4 (E 15)
IGNITION COIL2 (E 5)
IGNITION KEY REMINDER SWITCH4 (E 13)
IGNITION SWITCH3 (C-D 11)
INSTRUMENT CLUSTER4 (A-E 15)
INSTRUMENT PANEL LIGHT CONTROL4 (D-E 12)
INTERIOR LIGHT SWITCH4 (E 14)
LIGHT SWITCH4 (C-D 12)
MAIN FUSE PANEL1 (A 3)
MAIN RELAY2 (D 5)
NEUTRAL SAFETY SWITCH (A/T)1 (B 2)
PARKING LIGHT RELAY4 (C 14)
PASSIVE RESTRAINT CONTROL MODULE3 (A 11)
REAR WASHER MOTOR5 (D 17)
REAR WIPER/WASHER SWITCH5 (E 16)
SHIFT LOCK SERVO ASSY4 (A 12)
STARTER1 (B 3)
STOP LIGHT SWITCH5 (D 19)
TIMER/BUZZER UNIT4 (E 12)
TRUNK LIGHT5 (B 16)
WAC RELAY3 (B 8)
Page 1 of 6 MITCHELL 1 ARTICLE - WIRING DIAGRAMS 1991 WIRING DIAGRAMS Ford Motor Co.
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D - ADJUSTMENTS
1991 ENGINE PERFORMANCE Ford/Mercury - On-Vehicle Adjustm ents
ADJUSTMENTS
ENGINE MECHANICAL
Before beginning any on-vehicle adjustments to fuel or ignition systems, ensure engine mechanical condition is okay.
VALVE CLEARANCE
IGNITION TIMING
CAPRI
1. Place automatic transmission in Park or manual transmission in Neutral. Disconnect and plug hoses attached to vacuum diaphragm
assembly on distributor. Connect tachometer and timing light. Turn off all electrical loads.
2. Start engine, and warm it to operating temperature. Ensure idle speed is set to specification, adjusting if necessary. See IDLE SPEED &
MIXTURE . Determine initial timing. See IGNITION TIMING table. If base timing is not correct, loosen distributor mounting bolts
and rotate distributor until marks align. Tighten bolts to 14-18 ft. lbs. (19-25 N.m).
3. Increase engine RPM while observing timing light. Verify ignition timing advances. For Turbo models, go to step 5). For non-Turbo
models, continue with step 4).
4. On non-Turbo models, apply 16 in. Hg vacuum to chamber "A". Verify timing advances by 26-30 degrees. Remove vacuum source from
chamber "A". Apply 8 in. Hg vacuum to chamber "B" while observing timing. Verify timing advances by 3-7 degrees. Stop engine, and
remove test equipment.
5. On Turbo models, apply 20 in. Hg vacuum to advance diaphragm. Verify timing advances by 13-17 degrees. Disconnect vacuum source.
Apply 8 psi (.6 kg/cm
2 ) pressure to advance diaphragm. Verify timing retards by 3-7 degrees. Stop engine, and remove test equipment.
FESTIVA
1. Place manual transmission in Neutral or automatic transmission in Park. Turn all accessories off. Locate one-wire STI (Black) connector
near master cylinder. Using a jumper wire, connect STI terminal to ground. See Fig. 1
. Connect timing light and tachometer.

Fig. 1: Locating Self
-Test Input (STI) Connector
Courtesy of FORD MOTOR CO.
2. Start engine, and warm to operating temperature. Ensure idle speed is set to specification, adjusting if necessary. See IDLE SPEED &
MIXTURE .
3. Check initial timing. White timing mark should align with white mark on crankshaft pulley. If marks do not align, loosen distributor
mounting bolts and rotate distributor until marks align. Tighten bolts to 14-18 ft. lbs. (19-25 N.m).
4. Remove jumper wire. Increase engine RPM, and verify ignition timing advances beyond initial setting. Stop engine, and remove test
equipment.
IGNITION TIMING NOTE:All m odels are equipped with hydraulic lash adjusters. No adjustm ents are required.
Page 1 of 3 MITCHELL 1 ARTICLE - D - ADJUSTMENTS 1991 ENGINE PERFORMANCE Ford/Mercury - On-Vehicle Adjustments
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POWER STEERING PRESSURE SWITCH
1. Start engine and run it at idle. Remove connector from switch. Connect ohmmeter to switch terminals. Turn steering wheel from side to
side while observing ohmmeter.
2. Replace power steering switch if continuity does not exist with front wheels turned, or if continuity exists with wheels straight ahead.
THROTTLE POSITION SENSOR (1.6L)
Unplug connector from sensor. Connect ohmmeter to sensor terminals TP and SIGRTN (Orange and Blue/Yellow wires on mating connector).
Measure resistance at each throttle opening specified in THROTTLE POSITION SENSOR RESISTANCE
. Replace sensor if resistance is
not within specification.
THROTTLE POSITION SENSOR RESISTANCE
THROTTLE POSITION SWITCH (1.3L)
1. Ensure idle speed and ignition timing are adjusted to specification. Stop engine. Disconnect negative battery cable.
2. Unplug TPS connector at throttle body. Insert appropriate feeler gauge between throttle stop screw and stop lever. Check for continuity
between specified terminals on TPS connector. See ON-VEHICLE ADJUSTMENTS article and TPS CONTINUITY table.
TPS CONTINUITY
VANE AIRFLOW (VAF) METER
1. Check all wiring, harnesses, connectors and components for evidence of damage, overheating, shorting or looseness. If any defect exists,
repair as necessary.
2. Inspect vane airflow meter for damage and ensure measuring plate moves smoothly. Install BOB. Turn ignition on. Measure voltage
between BOB test pins VAF and ground on 1.3L, or between VAF and SIGRTN on 1.6L. Voltage measurements must be as specified in
VANE AIRFLOW METER VOLTAG
.
VANE AIRFLOW METER VOLTAGE
VANE AIR TEMPERATURE (VAT) SENSOR
1. Unplug connector from VAF meter. On 1.3L, connect ohmmeter to terminals VAT and ground (Green/Black and Black wires on mating
connector). On 1.6L, connect ohmmeter to VAF meter terminals VAT and SIGRTN (Brown and Blue/Yellow wires on mating
connector).
2. Measure intake air temperature. Measure resistance between specified terminals. See VANE AIR TEMPERATURE RESISTANCE
.
Replace VAF if resistance is not as specified.
Throttle Opening(1) Ohms
1/8989
1/41104
3/81278
1/21462
5/81480
3/41459
7/81144
Fully Open1072
(1)Resistance may vary by plus or minus 15 percent.
CAUT ION: DO NOT tam per with throttle stop screw at throttle lever. Doing so m ay result in dam age to the
throttle body.
Test Condition (1) Cont. Between IDL-TLCont. Between PSW-TL
.02" (.5 mm)YesNo
.03" (.7 mm)NoNo
Wide Open ThrottleNoYes
(1)Insert specified feeler gauge between throttle adjustment screw and stop lever.
Door Opening(1) Volts: 1.3L(1) Volts: 1.6L
Fully Closed.5-1.5(2) *
1/8.593.24
1/41.195.60
3/81.785.62
1/22.385.83
5/82.976.02
3/43.566.57
7/84.167.48
Fully Open4.5-5.07.87
(1)Voltage may vary by plus or minus 15 percent.
(2)Voltage not specified.
Page 3 of 7 MITCHELL 1 ARTICLE - I - SYSTEM/COMPONENT TESTS 1991 ENGINE PERFORMANCE Ford Motor Co. - Ford/Merc
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Fig. 1: Testing Canister Purge Solenoid

Courtesy of FORD MOTOR CO.
Carbon Canister
1. Start and run engine until it is at operating temperature. Stop engine. Remove carbon canister. Carbon canister on 1.3L is located under
brake booster. Carbon canister is located in right side of engine compartment near cowl panel on 1.6L.
2. Inspect carbon canister for presence of liquid fuel, as evidenced by odor or weight. Blow into air vent and ensure air exits fro m fu el
vapor inlet. Replace carbon canister if it contains fuel, or if air does not pass freely through it.
POSITIVE CRANKCASE VENTILATION (PCV)
1. Remove PCV valve from valve cover and disconnect it from PCV h o se . S h a ke va l ve vigo r o u sl y t o e n su r e p l u n ge r is fr e e t o mo ve .
Replace PCV valve if plunger is not free.
2. Idle engine until it is warm. Remove fresh air hose at inlet end. Plug nipple immediately to prevent stalling. Verify presence of vacuum at
inlet end of hose. If vacuum is not present, replace PCV valve or service hoses or loose oil dipstick.
THROTTLE CONTROLS
Dashpot
Disconnect PCV valve. Remove resonance chamber. Push dashpot rod in and then release it. Replace dashpot if rod does not go in slowly and
return quickly.
MISCELLANEOUS CONTROLS
A/C CLUTCH
A/C Clutch Relay
Remove relay from its socket near left headlight, in front of battery. Connect ohmmeter to contact terminals (Blue/Red and Black/White wires
on mating connector). Ohmmeter should indicate continuity. Supply 12 volts to remaining terminals (Green/Yellow and Yellow wires on
mating connector). Ohmmeter should indicate no continuity.
COOLING FAN
Cooling Fan
Unplug connector from cooling fan. Apply 12 volts to one terminal of fan connector. Ground remaining fan connector terminal. Replace fan if
it does not run.
Cooling Fan Control Relay
Remove relay from its socket near left headlight. Connect ohmmeter to contact terminals. Wire colors are Yellow/Red and Black on mating
connector on Festiva; Yellow/Green and Black on Capri. Ohmmeter should indicate continuity. Supply 12 volts to remaining 2 relay
terminals. Ohmmeter should indicate no continuity.
NOTE:Although som e of the controlled devices listed here are not technically engine perform ance
com ponents, they can affect driveability if they m alfunction.
Page 6 of 7 MITCHELL 1 ARTICLE - I - SYSTEM/COMPONENT TESTS 1991 ENGINE PERFORMANCE Ford Motor Co. - Ford/Merc
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GENERAL INFORMATION
Com puter Relearn Procedures
COMPUTER RELEARN PROCEDURES
Vehicles equipped with engine or transmission computers may require a relearn procedure after vehicle battery is disconnected. Many vehicle
computers memorize and store vehicle operation patterns for optimum driveability and performance. When vehicle battery is disconnected,
this memory is lost. The computer will use default data until new data from each key start is stored. As computer memorizes vehicle operation
for each new key start, driveability is restored. Vehicle computers may memorize vehicles operation patterns for 40 of more key starts.
Customers often complain of driveability problems during relearn stage because vehicle acts differently then before being serviced. Depending
on type and make of vehicle and how it is equipped, the following complaints (driveability problems) may exist:
Harsh Or Poor Shift Quality
Rough Or Unstable Idle
Hesitation Or Stumble
Rich Or Lean Running
Poor Fuel Mileage
These symptoms and complaints should disappear after a number of drive cycles have been memorized. To reduce the possibility of
complaints, after any service which requires battery power to be disconnected, vehicle should be road tested.
GENERIC COMPUTER RELEARN PROCEDURES
Some manufacturers identify a specific relearn procedure which will help establish suitable driveability during relearn stage. These procedures
are especially important if vehicle is equipped with and electronically controlled automatic transmission or transaxle. Always complete
procedure before returning vehicle to customer. The following general procedures are to be used if driveability problems are encountered after
power loss or battery has been disconnected. These procedures may provide an aid in eliminating these problems.
Automatic Transmission
Set parking brake, start engine in "P" or "N" position. Warm-up vehicle to normal operating temperature or until cooling fan cycles.
Allow vehicle to idle for one minute in "N" position. Select "D" and allow engine to idle for one minute.
Accelerate at normal throttle position (20-50%) until vehicle shifts into top gear.
Cruise at light to medium throttle.
Decelerate to a stop, allowing vehicle to downshift, and use brakes normally.
Process may be repeated as necessary.
Manual Transmission
Place transmission in Neutral position.
Ensure emergency brake has been set and all accessories are turned off.
Start engine and bring to normal operating temperature.
Allow vehicle to idle in Neutral for one minute.
Initial relearn is complete, and process will be completed during normal driving.
Copyr ight 2009 Mitchell Repair Information Company, LLC. All Rights Reserved.
Article GUID: A00012612
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2. Turn test switch knob to ON position (current through switch). Road test vehicle with vehicle accessories on (radio, air conditioner, etc).
After road test, turn ignition switch to LOCKED position and remove key. Connect ammeter terminals to test switch terminals. See Fig.
1. Select 10-amp scale.
3. Turn off all electrical accessories. Turn off interior lights, underhood lamp, trunk light, illuminated entry, etc. To avoid damaging
ammeter or obtaining a false meter reading, all accessories must be off before turning test switch knob to OFF position.
4. Turn test switch knob to OFF position to allow current to flow through ammeter. If meter reads wrong polarity, turn test switch to ON
position and reverse leads. Turn test switch to OFF position. Observe current reading. If reading is less than 2 amps, turn test switch to
ON position to keep electrical circuits powered-up.
5. Select low amp scale. Switch lead to the correct meter position. Turn test switch to OFF position and compare results to normal current
draw. See GENERAL MOTORS PARASITIC LOAD TABLE (MILLIAMPS)
. If current draw is unusually high for the vehicle's
overall electrical system, remove system fuses one at a time until current draw returns to normal.
6. Turn test switch to ON position each time door is opened or fuse is removed. Turn switch to OFF position to read current draw va l u e
through meter. When the cause of excessive current drain has been located and repaired, remove test switch and reconnect negative
battery cable to the negative battery terminal.
INTERMITTENT PARASITIC LOAD PROBLEMS
Intermittent parasitic load can occur because of a memory device that does not power down with ignition off. With an intermittent parasitic
load, battery draw can be greater than 1.0 amp.
To find an intermittent problem requires that an ammeter and Disconnect Tool (J-38758) test switch be connected and left in the circuit. See
Fig. 1
. Road test vehicle. After road test, turn ignition off and remove key.
Monitor the milliamps scale for 15-20 minutes after ignition is turned off. This allows monitoring memory devices to determine if they time out
and stop drawing memory current. The test switch is needed to protect ammeter when the vehicle is started.

Fig. 1: Connecting Kent
-Moore Disconnect Tool (J-38758)
Courtesy of GENERAL MOTORS CORP.
GENERAL MOTORS PARASITIC LOAD
ComponentNormal DrawMaximum DrawTime-Out (Minutes)
Anti-Theft System0.41.0.....
Auto Door Lock1.01.0.....
Body Control Module3.612.420
Central Processing System1.62.720
Electronic Control Module5.610.0.....
Electronic Level Control2.03.320
Heated Windshield Module0.30.4.....
HVAC Power Module1.01.0.....
Illuminated Entry1.01.01
Light Control Module0.51.0.....
Oil Level Module0.10.1.....
Page 2 of 4 MITCHELL 1 ARTICLE - GENERAL INFORMATION Parasitic Load Explanation & Test Procedures
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1991 GENERAL SERVICING
A/C Com pressor Refrigerant Oil Checking
ISOLATING COMPRESSOR
1. Connect service gauge set to the compressor service valves and open compressor valves slightly (turn in clockwise). Start engine and
operate air conditioning. Slowly turn compressor suction valve clockwise toward closed (front-seated) position.
2. When suction pressure is reduced to zero or less, turn off engine and compressor and quickly turn suction valve stem in to full front-
seated position. Suction pressure should be slightly above zero. Turn discharge valve into front-seated position.
3. To check oil level, slowly open compressor crankcase plug to relieve any remaining pressure. After oil level is corrected, cap service
gauge ports on both valves. Back-seat suction service valve to allow refrigerant to enter compressor. Open discharge valve halfway.
4. Loosen discharge service valve cap, allowing refrigerant pressure to force air out of compressor. Back-seat service valve and tighten cap.
Compressor is now ready for operation.
REFRIGERANT OIL
Only new, pure, moisture-free refrigerant oil should be used in the air conditioning system. This oil is highly refined and dehydrated to a point
where moisture content is less than 10 parts per million. The oil container must be tightly closed at all times when not in use, or moisture will
be absorbed into the refrigerant oil from the air.
SERVICING PRECAUTIONS
DISCHARGING SYSTEM PRECAUTIONS
If compressor has stem-type service valves, it can be isolated and removed without discharging entire system. See ISOLATING
COMPRESSOR at the beginning of this article. Otherwise, discharge system completely before loosening any fittings.
DISCONNECTING LINES & FITTINGS TEST
After system is discharged, carefully clean area around all fittings to be opened. Always use 2 wrenches when tightening or loosening fittings
to avoid twisting or distorting lines. Cap or plug all openings as soon as lines are removed. DO NOT remove caps until immediately before
connections are made. This will keep entry of air and moisture to a minimum.
CONNECTING LINES AND FITTINGS
A new gasket or "O" ring should be used in all instances when connecting lines or fittings. Dip "O" ring in new refrigerant oil and ensure it is
not twisted during installation. Always use 2 wrenches to prevent damage to lines and fittings.
PLACING SYSTEM IN OPERATION
After component service or replacement has been completed and all connections have been made, evacuate system thoroughly with a vacuum
pump. Charge system with proper amount of refrigerant and perform a leak test. See REFRIGERANT OIL & R-12 SPECIFICATIONS chart in
this section for system capacities. Be sure to check all fittings that have been opened. After system has been leak tested, make a system
performance check.
ATSUGI ROTARY VANE DRAIN & REFILL
1. Before checking and adjusting oil level, operate compressor at engine idling speed, with controls set for maximum cooling and high
blower speed, for 20 to 30 minutes to return oil to compressor.
2. Stop engine, discharge refrigerant and remove compressor from vehicle. See SERVICING PRECAUTIONS at beginning of article. Drain
compressor oil from compressor discharge port and measure the amount. Oil is sometimes hard to drain when compressor is cool.
Remove oil while compressor is warm.
3. If the amount drained is less than 3 ounces, conduct leak tests at system connections, and if necessary, repair or replace faulty parts.
Check purity of oil and adjust oil level as follows.
4. If amount drained was above 3 ounces, oil level is right. Pour in same amount as was drained. If amount drained was below 3 ounces,
pour in 3 ounces of new refrigerant oil.
BOSCH 6-CYL DRAIN & REFILL
1. Before checking and adjusting oil level, operate compressor at engine idling speed, with controls set for maximum cooling and high
blower speed, for 20 to 30 minutes to return oil to compressor.
2. Stop engine and discharge refrigerant. Remove refrigerant oil level inspection plug on side of compressor. Oil should be at lower lip of
threaded hole. Add necessary new refrigerant oil (if low). Replace inspection plug and tighten to 10-12 ft. lbs. (14-16 N.m). NOTE:Only com pressors with stem -type service valves can be isolated.
NOTE:Recent findings by the EPA indicate that refrigerant is harm ful to the earth's protective Ozone layer.
When discharging refrigerant, DO NOT allow refrigerant to enter the atm osphere. If available, use
refrigerant recovery/recycle system s when discharging system . Always follow m anufacturer's
instructions.
NOTE:Air conditioning system s will not norm ally need addition of refrigerant oil unless definite oil loss has
occurred due to ruptured lines, leaking com pressor seals, com pressor overhaul or com ponent
replacem ent.
Page 1 of 4 MITCHELL 1 ARTICLE - 1991 GENERAL SERVICING A/C Compressor Refrigerant Oil Checking
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