sensor FORD FESTIVA 1991 Workshop Manual

IDLE SPEED
While the engine is cold, the Idle Speed Control By-Pass Air (ISC-BPA) Valve increases idle speed to warm the engine quickly. At engine
temperatures less than 140°F (60°C), the valve is open. As the engine warms, the valve begins to close. The valve is fully closed at engine
temperatures higher than 140°F (60°C). Idle speed is also affected by various switches, sensors and load on the engine.
ELECTRONIC IGNITION SYSTEM
CAPRI
A pick-up coil within the distributor sends a signal to a Distributor-Mounted Ignition Module With Vacuum Advance (DMIVA) within the
distributor. The DMIVA then sends a signal which fires the coil. When the coil fires, the distributor directs high voltage current to the spark
plugs. The DMIVA system operates independently of the ECA.
FESTIVA
A pick-up coil within the distributor sends a signal to a transistorized ignition module on the coil bracket. A timing signal also goes from the
ECA to the ignition module. The ignition module then sends a signal which fires the coil. When the coil fires, the distributor directs high
voltage current to the spark plugs.
IGNITION TIMING CONTROL SYSTEM
CAPRI
Spark timing is controlled by vacuum and centrifugal advance mechanisms and by a signal from the ECA. The ECA does not affect ignition
timing on turbo models. On turbo models, a knock sensor and control unit retard ignition timing when knock occurs.
FESTIVA
The ECA generates a spark timing signal from data received from the BP, CPS and VAF. This signal goes to the ignition module. The ignition
module then sends a signal to fire the coil.
HIGH ALTITUDE SPARK ADVANCE CORRECTION
A barometric pressure sensor is incorporated into the ECA on Festiva and is a separate component on Capri. At high altitudes, the ECA sends
a signal to the ignition module to advance ignition timing. This feature is not used on turbo models.
KNOCK SENSOR (CAPRI)
A Knock Sensor (KS) generates a signal when knock occurs. A control unit processes this signal and then sends it to the ignition module to
retard spark timing. The KS is located in the engine block, near the oil pressure switch. This device is only used on 1.6L turbo engines.
KNOCK CONTROL UNIT (CAPRI)
The Knock Control Unit filters normal engine vibration signals from the KS, then sends a signal to the ignition module to retard spark timing.
This unit, used only on 1.6L turbo engines, is located on right side of engine compartment.
EMISSION SYSTEMS
DECELERATION SYSTEM (DASHPOT)
The deceleration control system closes the throttle plate gradually during deceleration. The dashpot prevents engine stalling on deceleration
and provides a smooth transition from deceleration to sudden acceleration.
EVAPORATIVE SYSTEM
CARBON CANISTER
The carbon canister stores vapors from the fuel tank until they are purged and burned in the engine. On Festiva, carbon canister is
located under the brake booster. On Capri, carbon canister is located on the right side of the engine compartment near the cowl panel.
CANISTER PURGE SOLENOID
This component is connected between the carbon canister and intake manifold. When the ECA sends a signal to the solenoid to open,
fuel vapors in the carbon canister are drawn into the engine.
CANISTER PURGE VALVE
This valve opens to purge vapors from the carbon canister into the engine intake system. The valve is part of the canister purge solenoid.
ROLLOVER VENT VALVE
This valve, located in front of the fuel tank, blocks the vapor line in case of vehicle rollover.
This valve, located in front of the fuel tank, blocks the vapor line in case of vehicle rollover.
CATALYTIC CONVERTER
The catalytic converter is in the exhaust system, between the exhaust manifold and the muffler. It converts certain pollutants in the exhaust
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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
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Back To Article
GENERAL INFORMATION
Com m only Used Abbreviations
* PLEASE READ THIS FIRST *
"A"
A
Amperes
ABS
Anti-Lock Brakes
ABRS
Air Bag Restraint System
AC
Alternating Current
A/C
Air Conditioning
ACCS
A/C Cycling Switch
ACCUM
Accumulator
ACCY
Accessory
ACT
Air Charge Temperature Sensor
ADJ
Adjust or Adjustable
ADV
Advance
AFS
Airflow Sensor
AI
Air Injection
AIR or A.I.R.
Air Injection Reactor
AIS
Air Injection System
Alt.
Alternator or Altitude
Amp./amp/amps
Ampere NOTE:T his article is intended for general inform ation purposes only. T his inform ation m ay not apply to all
m akes and m odels. Not all abbreviations are covered as m anufacturers add new ones every day.
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ASCS
Air Suction Control Solenoid
ASD
Auto Shutdown
ASDM
Air Bag System Diagnostic Module
ASV
Air Suction Valve
A/T
Automatic Transmission/Transaxle
ATC
Automatic Temperature Control
ATDC
After Top Dead Center
ATF
Automatic Transmission Fluid
ATS
Air Temperature Sensor
Aux.
Auxiliary
Avg.
Average
AXOD
Automatic Transaxle Overdrive (Ford Models Only)
"B"
BAC
By-Pass Air Control
BAP
Barometric Absolute Pressure Sensor
BARO
Barometric
Batt.
Battery
Bbl.
Barrel (Example: 4-Bbl.)
BCM
Body Control Module
BHP
Brake Horsepower
BMAP
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Barometric and Manifold Absolute Pressure Sensor
BOO
Brake On-Off Switch
B/P
Backpressure
BPS
Barometric Pressure Sensor
BPT
Backpressure Transducer
BTDC
Before Top Dead Center
BTU
British Thermal Unit
BVSV
Bimetallic Vacuum Switching Valve
"C"
° C
Celsius (Degrees)
Calif.
California
CANP
Canister Purge
CARB
California Air Resources Board
CAT
Catalytic Converter
CB
Circuit Breaker
CBD
Closed Bowl Distributor
cc
cubic centimeter
CCC
Computer Command Control
CCD
Computer Controlled Dwell
CCOT
Cycling Clutch Orifice Tube
CCW
Counterclockwise
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CDI
Capacitor Discharge Ignition
CEC
Computerized Engine Control
CID
Cubic Inch Displacement
cm
Centimeter
CMP
Camshaft Position Sensor
CO
Carbon Monoxide
CO
2
Carbon Dioxide
Cont.
Continued
CONV
Convertible
CP
Canister Purge
CKP
Crankshaft Position Sensor
CTS
Coolant Temperature Sensor
Cu. In.
Cubic Inch
CVC
Constant Vacuum Control
CV
Check Valve or Constant Velocity
CW
Clockwise
CYL or Cyl.
Cylinder
C
3 I
Computer Controlled Coil Ignition
C
4
Computer Controlled Catalytic Converter
"D"
"D"
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EBL
Electronic Back Light
ECM
Engine Control Module
ECT
Engine Coolant Temperature Sensor
EDIS
Electronic Distributorless Ignition System
EEC
Electronic Engine Control
EECS
Evaporative Emission Control System
EEPROM
Electronically Erasable PROM
EFE
Early Fuel Evaporation
EGO
Exhaust Gas Oxygen Sensor
EGR
Exhaust Gas Recirculation
ESA
Electronic Spark Advance
ESC
Electronic Spark Control
EST
Electronic Spark Timing
EVAP
Fuel Evaporative System
EVIC
Electronic Vehicle Information Center
EVP
EGR Valve Position Sensor
Exc.
Except
"F"
° F
Fahrenheit (Degrees)
F/B
Fuse Block
Fed.
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Federal
FI
Fuel Injection
FICU
Fuel Injection Control Unit
FIPL
Fuel Injector Pump Lever
FPR-VSV
Fuel Pressure Regulator Vacuum Switching Valve
Ft. Lbs.
Foot Pounds
FWD
Front Wheel Drive
"G"
g
gr a ms
Gals.
ga l l o n s
GND or GRND
Ground
"H"
HAC
High Altitude Compensation
HC
Hydrocarbons
H/D
Heavy Duty
HO2S
Heated Exhaust Gas Oxygen Sensor
Hg
Mercury
Hgt.
Height
HLDT
Headlight
HO
High Output
HO2S
Heated Oxygen Sensor
HP
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"J"
J/B
Junction Block
"K"
KAPWR
Keep Alive Power
k/ohms
kilo-ohms (1000 ohms)
kg
Kilograms (weight)
kg/cm
2
Kilograms Per Square Centimeter
KM/H
Kilometers Per Hour
KOEO
Key On, Engine Off
KOER
Ke y On , E n gin e R u n n in g
KS
Knock Sensor
kW
Kilowatt
kV
Kilovolt
"L"
L
Liter
lbs. (Lbs. when used in table)
Pounds
LCD
Liquid Crystal Display
L/D
Light Duty
LDP
Leak Detection Pump (Part of EVAP system.)
LED
Light Emitting Diode
LH
Left Hand
"M"
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mA
Milliamps
MA or MAF
Mass Airflow
MAFS
Mass Airflow Sensor
MAP
Manifold Absolute Pressure
MAT
Manifold Air Temperature
Mem.
Memory
MEM-CAL
Memory Calibration Chip
mfd.
Microfarads
MFI
Multiport Fuel Injection
MIL
Malfunction Indicator Light
MPI
Multi-Point (Fuel) Injection
mm
Millimeters
MPH
Miles Per Hour
mV
Millivolts
"N"
NA
Not Available
NGS
New Generation Star
N.m
Newton Meter
No.
Number
Nos.
Numbers
NOx
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