ECU FORD FESTIVA 1991 User Guide

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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Autolamp Control RelayHeadlight Systems; Daytime Running Lights
Automatic Shutdown (ASD) RelayEngine Performance; Generators & Regulators
Autostick SwitchEngine Performance
Auxiliary Battery RelayGenerators & Regulators
Back-Up LightsBack-Up Lights; Exterior Lights
Barometric (BARO) Pressure SensorEngine Performance
BatteryPower Distribution
Battery Temperature SensorEngine Performance
Body Control ModuleBody Control Computer; Anti-Theft System; Daytime Running
Lights; Engine Performance; Headlight Systems; Warning Systems
Boost Control SolenoidEngine Performance
Boost SensorEngine Performance
Brake Fluid Level SwitchAnalog Instrument Panels
Brake On/Off (BOO) SwitchCruise Control Systems; Engine Performance; Shift Interlock
Systems
Buzzer ModuleWarning Systems
Camshaft Position (CMP) SensorEngine Performance
Central Control ModuleAnti-Theft System
ClockspringAir Bag Restraint System; Cruise Control Systems; Steering
Column Switches
Clutch Pedal Position SwitchStarters
Clutch Start SwitchStarters
Combination MeterAnalog Instrument Panels
Constant Control Relay Module (CCRM)Engine Performance; Electric Cooling Fans
Convenience CenterPower Distribution; Illumination/Interior Lights
Convertible Top MotorPower Convertible Top
Convertible Top SwitchPower Convertible Top
Crankshaft Position (CKP) SensorEngine Performance
Cruise Control ModuleCruise Control Systems
Cruise Control SwitchCruise Control Systems
Condenser Fan Relay(s)Electric Cooling Fans
Data Link Connector (DLC)Engine Performance
Da yt ime R u n n in g Ligh t s M o d u l eDaytime Running Lights; Exterior Lights
Defogger RelayRear Window Defogger
Diagnostic Energy Reserve Module (DERM)Air Bag Restraint System
Discriminating Sensor (Air Bag)Air Bag Restraint System
DistributorEngine Performance
Door Lock ActuatorsPower Door Locks; Remote Keyless Entry
Door Lock Relay(s)Power Door Locks
Electrochromic MirrorPower Mirrors
Electronic Level Control (ELC) Height SensorElectronic Suspension
Electronic Level Control (ELC) ModuleElectronic Suspension
Engine Coolant Temperature (ECT) Sending UnitAnalog Instrument Panels
Engine Coolant Temperature (ECT) SensorEngine Performance
Engine Control ModuleEngine Performance; Generators & Regulators; Starters
ETACS ECUWarning Systems; Power Windows; Remote Keyless Entry
Evaporative (EVAP) Emissions CanisterEngine Performance
EVAP Canister Purge SolenoidEngine Performance
EVAP Canister Vent SolenoidEngine Performance
Exhaust Gas Recirculation (EGR) ValveEngine Performance
Fuel Tank Vacuum SensorEngine Performance
F o g Ligh t sHeadlight Systems; Daytime Running Lights
F o g Ligh t R e l a yHeadlight Systems; Daytime Running Lights
Fuel Door Release SolenoidPower Fuel Door Release
Fuel Gauge Sending UnitAnalog Instrument Panels
Fuel InjectorsEngine Performance
Fuel PumpEngine Performance
Fuel Pump RelayEngine Performance; Power Distribution
Fuse/Relay BlockPower Distribution
Fusible LinksPower Distribution; Generators & Regulators; Starters
GeneratorGenerators & Regulators; Engine Performance; Power Distribution
Generic Electronic Module (GEM)Body Control Modules; Electronic Suspension
Glow Plug RelayEngine Performance
Glow PlugsEngine Performance
GroundsGround Distribution
Headlight Door ModuleHeadlight Doors
Headlight RelayHeadlight Systems; Daytime Running Lights
HeadlightsHeadlight Systems; Daytime Running Lights
Heated Oxygen Sensor(s) (HO2S)Engine Performance
Heated Windshield Control ModuleHeated Windshields
Page 4 of 6 MITCHELL 1 ARTICLE - GENERAL INFORMATION Using Mitchell1's Wiring Diagrams
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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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1. Position new gasket on exhaust manifold, and install turbocharger onto studs. Install 4 retaining nuts and tighten to specification. See
TORQUE SPECIFICATIONS
table at end of article.
2. Remove oil supply line from turbocharger. Position new (2-piece) exhaust gasket on cylinder head with heavy gasket installed first .
Carefully position turbocharger assembly in engine compartment and slide exhaust manifold on studs. Position heater tube bracket onto
exhaust stud. Install 11 retaining nuts onto exhaust manifold and tighten to specification. See TORQUE SPECIFICATIONS
table at
end of article. Tighten heater tube clamp bolt securely.
3. Raise vehicle. Position new gasket and install 2 retaining bolts on heater tube outlet. Install 2 retaining bolts into turbocharger support
bracket and tighten bolts to specification.
4. Connect coolant return hose. Connect oil return hose and secure with clamp. Position exhaust pipe onto turbocharger, and start nuts
and washers. Install 2 retaining bolts on exhaust hanger at engine. Slide on 2 rubber exhaust hangers at catalytic converter. Tighten
exhaust pipe retaining nuts to specification. Lower vehicle.
5. Install retaining bolt and brass washers on oil supply line, carefully position oil line into vehicle and hand-start bolt into engine block.
Connect and finger tighten oil line to turbocharger. Tighten oil line bolt and oil supply line on turbocharger to specification.
6. Connect coolant supply hose. Position air cleaner duct tube on turbocharger and tighten clamp. Install 2 screws retaining air cleaner
duct tube. Position power steering pump bracket on engine, and install 2 retaining bolts and one retaining nut. Tighten to specification.
Position power steering pump on mounting bracket, and install though bolt and adjuster. Connect lower radiator hose. Install power
steering belt. Position upper heat shield and install 2 retaining bolts finger tight.
7. Position lower heat shield and install three retaining bolts finger tight. Tighten all heat shield bolts to specification. Connect O2 sensor
and install connector into its retaining clip. See TORQUE SPECIFICATIONS
table at end of article. Position intercooler hose on
turbocharger and secure with clamp. Install throttle body air intake tube. Connect negative battery cable. Refill cooling system.
CYLINDER HEAD
Removal (1.3L)
1. Disconnect battery ground cable. Mark and disconnect fuel lines at fuel pump. Remove accessory belts, water pump pulley, crankshaft
pulley, timing belt covers, timing belt tensioner, timing belt, valve cover and exhaust and intake manifolds. Drain cooling system.
2. Mark and remove electrical connectors and vacuum hoses. Remove spark plug wires from spark plugs, and remove spark plugs. Remove
distributor cap. Disconnect vacuum hoses and distributor wiring.
3. Index distributor-to-mount position and remove hold-down bolt. Remove distributor assembly. Remove engine ground strap. Remove
front and rear engine lifting hooks. Remove upper radiator hose, by-pass hose and bracket.
4. Remove bolts retaining rocker arm shaft. Remove rocker arm assemblies. Remove cylinder head bolts. Remove head and gasket.
Inspection (1.3L)
1. Thoroughly clean and check gasket mating surface of cylinder head and block. Check cylinder for cracks, nicks, burrs or damage. Using
a straightedge and feeler gauge, check warpage over entire gasket area. Ensure cylinder head and/or block warpage does not
exceed .006" (.15 mm).
2. If warpage exceeds .006" (.15 mm), machine cylinder head and/or block gasket surface. Maximum machining allowed is .008" (.20 mm).
If more machining is required, replace block and/or cylinder head.
Installation (1.3L)
1. Place new head gasket properly on block. Carefully place cylinder head in position on block. Install head bolts. Tighten bolts in
sequence and in 2 steps. See Fig. 1
.
2. While tightening rocker arm shaft, slide shaft springs away from retaining bolt to prevent pinching springs. Tighten rocker arm shaft bolts
in sequence and to specification. See Fig. 5
. To complete installation, reverse removal procedure. Tighten all bolts/nuts to
specification. Fill all fluids to proper levels. NOTE:T urbocharger-to-exhaust m anifold m ounting nuts are of special quality. Ensure correct nuts are
used.
NOTE:Ensure one brass washer is positioned on each side of oil line fitting.
NOTE:Feed O2 sensor wire through upper heat shield. Install wire retainer under LH bolt.
NOTE:If turbocharger was replaced: Disconnect ignition coil, crank engine for 20 seconds, connect ignition
coil, start engine and run at idle for 30 seconds and check for leaks.
NOTE:If original tim ing belt is being reused, m ark direction of rotation for installation reference.
Page 4 of 19 MITCHELL 1 ARTICLE - ENGINE OVERHAUL 1991-92 FORD MOTOR CO. ENGINES 1.3L & 1.6L 4-Cylinder
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CEC
Computerized Engine Controls
DOHC
Dual Overhead Cam
DPFE
Differential Pressure Feedback EGR Valve
EAIR
Electric Air Injection System
EAIR DV
Electric Air Injection System Diverter Valve
ECM
Electronic Control Module
ECU
Electronic Control Unit
EGR
Exhaust Gas Recirculation
EVRS
EGR Vacuum Regulator Solenoid
EVAP
Fuel Evaporative System
EVAP-AAC
EVAP Auxiliary Air Control
EVAP-BPSV
EVAP By-Pass Solenoid Valve
EVAP-BVSV
EVAP Bimetallic Vacuum Switching Valve
EVAP-CAV
EVAP Canister Air Valve
EVAP-CCV
EVAP Control Canister Close Valve
EVAP-CCVSV
EVAP Control Canister Vent Shut Valve
EVAP-CCVVSV
EVAP Closed Canister Valve Vacuum Switching Valve
EVAP-CDCV
EVAP Canister Drain Cut Valve
EVAP-CKV
EVAP Check Valve
EVAP-CPCS
EVAP Canister Purge Control Solenoid
Page 6 of 9 MITCHELL 1 ARTICLE - EMISSION CONTROL APPLICATIONS Emission Applications - Ford Motor Co. - Imports (1968-
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Removal
Drain radiator and remove negative battery cable. Disconnect throttle cable. Remove air duct from throttle body. Disconnect throttle position
sensor/switch connector. Mark all coolant and vacuum hoses for reassembly reference and remove from throttle body. See Fig. 4
. Remove
intake plenum bolts and remove intake plenum and gasket.
Installation
To install, reverse removal procedure. Use NEW intake plenum-to-intake manifold gasket. Tighten bolts to specification, see TORQUE
SPECIFICATIONS at end of article.
OXYGEN (O2) SENSOR
Removal & Installation
Disconnect negative battery cable. Disconnect wire harness connector, and remove oxygen sensor. If exhaust sensor is difficult to remove, use
rust penetrant to avoid possible damage to exhaust threads. If new sensor is not pre-coated with anti-seize, apply anti-seize compound to
sensor threads. DO NOT remove anti-seize from sensor. To install, tighten sensor and attach wire harness connector.
THROTTLE BODY
Removal & Installation
Drain radiator and remove negative battery cable. Remove resonance chamber. Disconnect throttle cable. Remove air duct. Mark all coolant
and vacuum hoses for reassembly reference and remove from throttle body. Disconnect throttle position sensor/switch connector. Remove
throttle body nuts and bolts. Remove throttle body and gasket. To install, reverse removal procedure using NEW throttle body-to-intake
plenum gasket.
THROTTLE POSITION SENSOR/SWITCH
Removal & Installation
Disconnect negative battery cable. Disconnect throttle position sensor/switch connector. Remove attaching bolts. Remove sensor/switch from
throttle body. To install, reverse removal procedure.
TURBOCHARGER
Removal
1. Drain radiator and remove negative battery cable. Remove throttle body air intake tube. Disconnect intercooler hose from turbocharger
assembly. Disconnect O2 sensor. Remove lower heat shield retaining bolts and lower heat shield from turbocharger. Remove upper heat
shield retaining bolts and upper heat shield from exhaust manifold.
2. Slide O2 sensor wire and guide through upper heat shield. Remove side heat shield retaining bolts from turbocharger, and remove sid e
heat shield. Remove power steering belt. Remove power steering pump through bolt and adjuster nuts and bolts. Disconnect lower
radiator hose from water pump.
3. Pull pump from bracket, and position pump to access mounting bracket retaining nut and bolts. Remove mounting bracket-to-engine nut
and bolts and remove bracket. Remove air cleaner duct retaining screws. Loosen clamp at turbocharger and move duct tube out of way.
Disconnect coolant supply hose at turbocharger.
4. Remove bolt and sealing washers attaching oil supply line at engine block. Raise vehicle on hoist. Remove nuts and washers from
exhaust pipe flange. Remove bolts attaching exhaust hanger to engine block. Slide rubber exhaust hangers from catalytic converter. Pull
exhaust pipe downward and to left side of vehicle. Disconnect oil return hose from turbocharger. Disconnect coolant return hose fro m
turbocharger.
5. Remove turbocharger support bracket retaining bolts. Remove coolant by-pass tube outlet-to-water pump bolts. Lower vehicle. Loosen
retaining clamp bolt on coolant by-pass tube at rear of cylinder head. Remove 11 retaining nuts from exhaust manifold. Position coolant
by-pass tube out of way after pulling bracket from exhaust stud.
6. Remove exhaust manifold by pulling off studs and moving assembly towards right side of engine compartment, clearing cooling fan.
With assembly removed from vehicle, remove turbocharger-to-exhaust manifold nuts. Separate assembly and discard gasket.
Installation
1. Install NEW gasket on exhaust manifold and install turbocharger onto studs. Install turbocharger-to-exhaust manifold nuts. Remo ve o il
supply line from turbocharger. Install NEW exhaust gasket on cylinder head. Install turbocharger and exhaust manifold assembly onto
studs. Install coolant by-pass tube bracket onto exhaust stud. Install 11 retaining nuts onto exhaust manifold.
2. Securely tighten heater tube clamp bolt. Raise vehicle. Install coolant by-pass tube outlet-to-water pump bolts. Install turbocharger
support bracket retaining bolts. Connect coolant return hose to turbocharger. Connect oil return hose to turbocharger. Install exhaust
pipe onto turbocharger, and hand tighten nuts and washers. Install bolts attaching exhaust hanger to engine block.
3. Slide rubber exhaust hangers onto catalytic converter. Tighten exhaust pipe nuts and washers. Lower vehicle. Install bolt and sealing
washers attaching oil supply line at engine block. Install oil supply line onto turbocharger. To complete installation, reverse removal
procedure. Tighten bolts and nuts to specification, see TORQUE SPECIFICATIONS
at end of article. NOTE:T o prevent dust and dirt from entering intake m anifold ports, cover ports with clean cloth after
rem oving intake plenum .
WARNING:DO NOT rem ove oxygen sensor when engine is hot.
NOTE:Clean throttle body exterior before rem oval.
CAUT ION: Before installing turbocharger, put .8 oz. (25 m l) engine oil into turbocharger oil inlet.
Page 4 of 5 MITCHELL 1 ARTICLE - N - REMOVE/INSTALL/OVERHAUL 1991 ENGINE PERFORMANCE Ford/Mercury Removal, O
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gases into harmless substances.
PCV VALVE
The Positive Crankcase Ventilation (PCV) valve, located in the valve cover, controls the flow of blow-by gas from the crankcase to the intake
man ifo l d .
SELF-DIAGNOSTIC SYSTEM
The ECA monitors its inputs and outputs. When it detects a malfunction, it sets a code in the ECA and sends a signal to the CHECK ENGINE
warning light. The light remains on until the malfunction is repaired. Trouble codes may be accessed at the Self-Test Output (STO) and Self-
Test Input (STI) connectors, near the battery.
If a sensor fails, the ECA will use a substitute value in its calculations to permit continued engine operation. In this condition, the vehicle will
run, but driveability may be poor. Intermittent failures may result in the CHECK ENGINE warning light flickering or going out after the fault
goes away. The corresponding trouble code, however, will be stored in the ECA. If fault does not recur, the related code will be erased from
ECA memory.
CHECK ENGINE LIGHT
Hard failures cause the CHECK ENGINE warning light to come on and remain on until the malfunction is repaired. If the warning light comes
on and stays on during vehicle operation, determine and correct the cause of the malfunction. NOTE:For additional inform ation and operating procedures for the self-diagnostic system , refer to T EST S
W/CODES article in the ENGINE PERFORMANCE Section.
Copyr ight 2009 Mitchell Repair Information Company, LLC. All Rights Reserved.
Article GUID: A00022697
Page 6 of 6 MITCHELL 1 ARTICLE - E - THEORY/OPERATION 1991 ENGINE PERFORMANCE Ford/Mercury Theory & Operation
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Back To Article
GENERAL INFORMATION
Engine Perform ance Safety Precautions
Always refer to Emission Decal in engine compartment before servicing vehicle. If manual and decal differ, always use decal
specifications.
Do not allow or create a condition of misfire in more than one cylinder for an extended period of time. Damage to converter may occur
due to loading converter with unburned air/fuel mixture.
Always turn ignition off and disconnect negative battery cable BEFORE disconnecting or connecting computer or other electrical
components.
DO NOT drop or shock electrical components such as computer, airflow meter, etc.
DO NOT use fuel system cleaning compounds that are not recommended by the manufacturer. Damage to gaskets, diaphragm materials
and catalytic converter may result.
Before performing a compression test or cranking engine using a remote starter switch, disconnect coil wire from distributor and secure it
to a good engine ground, or disable ignition.
Before disconnecting any fuel system component, ensure fuel system pressure is released.
Use a shop towel to absorb any spilled fuel to prevent fire.
DO NOT create sparks or have an open flame near battery.
If any fuel system components such as hoses or clamps are replaced, ensure they are replaced with components designed for fuel system
use.
Always reassemble throttle body components with new gaskets, "O" rings and seals.
If equipped with an inertia switch, DO NOT reset switch until fuel system has been inspected for leaks.
We a r sa fe t y go ggl e s wh e n d r il l in g o r gr in d in g.
Wear proper clothing which protects against chemicals and other hazards.
Copyr ight 2009 Mitchell Repair Information Company, LLC. All Rights Reserved.
Article GUID: A00002342
Page 1 of 1 MITCHELL 1 ARTICLE - GENERAL INFORMATION Engine Performance Safety Precautions
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The voltage controlled driver inside the computer operates much like a simple switch because it does not need to worry about limiting current
flow. Recall, this driver typically requires injector circuits with a total leg resistance of 12 or more ohms.
The driver is either ON, closing/completing the circuit (eliminating the voltage-drop), or OFF, opening the circuit (causing a total voltage
drop).
Some manufacturers call it a "saturated switch" driver. This is because when switched ON, the driver allows the magnetic field in the injector
to build to saturation. This is the same "saturation" property that you are familiar with for an ignition coil.
There are two ways "high" resistance can be built into an injector circuit to limit current flow. One method uses an external solenoid resistor
and a low resistance injector, while the other uses a high resistance injector without the solenoid resistor. See the left side of Fig. Fig. 1
.
In terms of injection opening time, the external resistor voltage controlled circuit is somewhat faster than the voltage controlled high resistance
injector circuit. The trend, however, seems to be moving toward use of this latter type of circuit due to its lower cost and reliability. The ECU
can compensate for slower opening times by increasing injector pulse width accordingly.

Fig. 1: Injector Driver Types
- Current and Voltage
CURRENT CONTROLLED CIRCUIT ("PEAK & HOLD")
The current controlled driver inside the computer is more complex than a voltage controlled driver because as the name implies, it has to limit
current flow in addition to its ON-OFF switching function. Recall, this driver typically requires injector circuits with a total leg resistance of
less than 12 ohms.
Once the driver is turned ON, it will not limit current flow until enough time has passed for the injector pintle to open. This period is preset by
the particular manufacturer/system based on the amount of current flow needed to open their injector. This is typically between two and six
amps. Some manufacturers refer to this as the "peak" time, referring to the fact that current flow is allowed to "peak" (to open the injector).
Once the injector pintle is open, the amp flow is considerably reduced for the rest of the pulse duration to protect the injector from
overheating. This is okay because very little amperage is needed to hold the injector open, typically in the area of one amp or less. Some
manufacturers refer to this as the "hold" time, meaning that just enough current is allowed through the circuit to "hold" the already-open
injector open.
There are a couple methods of reducing the current. The most common trims back the available voltage for the circuit, similar to turning down
a light at home with a dimmer.
The other method involves repeatedly cycling the circuit ON-OFF. It does this so fast that the magnetic field never collapses and the pintle
stays open, but the current is still significantly reduced. See the right side of Fig. Fig. 1
for an illustration.
The advantage to the current controlled driver circuit is the short time period from when the driver transistor goes ON to when the injector
actually opens. This is a function of the speed with which current flow reaches its peak due to the low circuit resistance. Also, the injector
closes faster when the driver turns OFF because of the lower holding current.
THE TWO WAYS INJECTOR CIRCUITS ARE WIRED
NOTE:Never apply battery voltage directly across a low resistance injector. T his will cause injector dam age
from solenoid coil overheating.
NOTE:Never apply battery voltage directly across a low resistance injector. T his will cause injector dam age
from solenoid coil overheating.
Page 5 of 19 MITCHELL 1 ARTICLE - GENERAL INFORMATION Waveforms - Injector Pattern Tutorial
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Fig. 1: Atsugi Rotary Vane Compressor

Courtesy of NISSAN MOTOR CO., U.S.A.
BOSCH 6-CYL CLUTCH R & I
Removal
1. Hold clutch plate and remove shaft nut. Using Clutch Plate Remover (64 5 00), remove clutch plate. Using snap ring pliers, remo ve
circlip and remove pulley assembly.
2. If pulley bearing is being replaced, remove circlip at rear of pulley. Press bearing and spacer from pulley. Press in new bearing with
spacer and replace circlip.
Installation
1. Clean all surfaces. Install pulley assembly on compressor and install circlip. Ensure clutch plate shim is in place on shaft. Install clutch
plate and nut. Tighten nut to 13-14 ft. lbs. (18-20 N.m).
2. Using a feeler gauge, check clutch plate-to-pulley clearance. Clearance should be .028-.051" (.7-1.3 mm). If clearance is not correct,
remove clutch plate and replace clutch plate shim. See Fig. 2
.
BOSCH 6-CYL SHAFT SEAL R & I
Removal & Installation
1. Remove clutch plate. Remove shaft key and circlip. Using Seal Seat Remover/Installer (64 5 030), remove seal seat.
2. Using Seal Remover/Installer (64 5 040), remove shaft seal by turning seal slightly clockwise to disengage tangs and pull out shaft seal.
Remo ve "O" rin g seal .
3. Coat new "O" ring seal with refrigerant oil and install. Coat new shaft seal with refrigerant oil and install shaft seal on Seal
Remover/Installer (64 5 040). Ensure alignment of shaft seal and shaft machine surfaces. Insert shaft seal and turn slightly
counterclockwise to secure on shaft.
4. Using sleeve from Seal Seat Remover/Installer (64 5 030), push seal seat into compressor and install circlip. Install shaft key and clutch
plate. Check compressor oil level before charging system.
Page 2 of 18 MITCHELL 1 ARTICLE - A/C COMPRESSOR SERVICING 1991 GENERAL SERVICING Compressor Service
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