1991 FORD FESTIVA light

ABBREVIATIONS
ACL
Air Cleaner (Thermostatic Air Cleaner)
AIS
Air Injection System
AIS-ACV
AIS Air Control Valve
AIS-AMV
AIS Air Management Valve
AIS-ASS
AIS Air Switching Solenoid
AIS-ASV
AIS Air Switching Valve
AIS-BPV
AIS By-Pass Valve
AIS-CKV
AIS Check Valve
AIS-CV
AIS Combination Valve
AIS-DV
AIS Diverter Valve
AIS-RV
AIS Relief Valve
AIS-SOL
AIS Solenoid
AIS-SV
AIS Solenoid Valve
CS, EGR-PS, SPK-CC
(1)For quick reference, major emission control systems and devices are listed in bold type; components and other related devices are
listed in light type.
(2)California only.
(3)A/T only.
(4)Federal only.
(5)M/T only.
(6)2.8L & California 2.3L.
(7)Except Federal models.
(8)2.0L only.
(9)2.3L California only.
(10)M/T only.
(11)California with M/T.
(12)Some models.
(13)Federal with M/T.
(14)M/T models with engine family VBT.
(15)Electronically controlled.
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FLV
Fill Limit Valve
FR
Fill Pipe Restrictor
FVV
Fuel Vapor Valve
HO2S
Heated Oxygen Sensor
MFI
Multiport Fuel Injection
MFI-MAF
MFI Mass Airflow Sensor
MIL
Malfunction Indicator Light
OC
Oxidation Catalytic Converter
OHC
Overhead Cam
ORVR
On-Board Refueling Vapor Recovery
ORVR-COV
ORVR Cut-Off Valve
ORVR-CV
ORVR Control Valve
ORVR-FMV
ORVR Flow Management Valve
ORVR-FTVCV
ORVR Fuel Tank Vapor Control Valve
ORVR-FTVRV
ORVR Fuel Tank Vapor Recirculation Valve
ORVR-LV
ORVR Leveling Valve
ORVR-OCKV
ORVR Overfill Check Valve
ORVR-RCV
ORVR Refueling Control Valve
ORVR-VCV
ORVR Vapor Cut Valve
ORVR-VRV
ORVR Vapor Recirculating Valve
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J - PIN VOLT AGE CHART S
1991 ENGINE PERFORMANCE Ford/Mercury Pin Voltage Charts
INTRODUCTION
Pin voltage charts are supplied to reduce diagnostic time. Checking pin voltages at the Electronic Control Assembly (ECA) determin es
whether it is receiving and transmitting proper voltage signals. Charts may also help determine if ECA wiring harness is shorted or opened.

Fig. 1: Identifying ECA Connector Terminals (Festiva)

Courtesy of FORD MOTOR CO.

Fig. 2: Identifying ECA Connector Terminals (Capri)

Courtesy of FORD MOTOR CO.
NOTE:Unless stated otherwise in testing procedures, perform all voltage tests using a Digital Volt-Ohm m eter
(DVOM) with a m inim um 10-m egohm input im pedance. Voltage readings m ay vary slightly due to
battery condition or charging rate.
NOTE:For additional pin voltage inform ation, see appropriate trouble code inform ation in G - T EST S W/
CODES article in the ENGINE PERFORMANCE Section.
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Connect BOB. Remove dust cover from BP sensor, located on passenger side cowl. Turn ignition on. Connect vacuum pump to BP sensor.
Measure voltage between pins BP and SIGRTN on BOB while applying vacuum to BP sensor. See BAROMETRIC PRESSURE SENSOR
OUTPUT VOLTAGE . Replace BP sensor if voltage is not as specified.
BAROMETRIC PRESSURE SENSOR OUTPUT VOLTAGE
BRAKE ON-OFF (BOO) SWITCH
Unplug connector from BOO switch at brake pedal. Connect ohmmeter to switch terminals. With pedal released, ohmmeter should indicate no
continuity. Ohmmeter should indicate continuity with pedal depressed.
CLUTCH ENGAGE SWITCH (CES)
Unplug connector from CES switch at clutch pedal. Connect ohmmeter to switch terminals. With pedal released, ohmmeter should indicate
continuity. Ohmmeter should indicate no continuity with pedal depressed.
CRANKSHAFT POSITION SENSOR (CPS) (1.3L)
Unplug 3-wire connector from distributor. Measure resistance between CPS terminal on distributor (Yellow/Blue wire) and ground. Replace
CPS if resistance is not 210-250 ohms.
CYLINDER IDENTIFICATION (CID) SENSOR (1.6L)
Turn ignition off. Connect BOB, leaving ECA connected. Turn ignition on, but DO NOT start engine. Measure voltage at BOB pin No. 34
(Yellow wire). Volt- meter should indicate less than one volt or more than 10 volts. Start engine and run at idle. Voltmeter should indicate 3-
5 volts. Replace CID sensor if voltage is not as specified.
ENGINE COOLANT TEMPERATURE (ECT) SENSOR
1. Remove ECT sensor. ECT sensor is threaded into top of lower intake manifold on 1.3L, and on underside of intake manifold on 1.6L.
Place ECT sensor and thermometer into container of coolant.
2. Connect ohmmeter to coolant temperature sensor terminals. Cool or heat container. Note resistance at specified temperatures. See
ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE
. Replace ECT sensor if resistance is not within specification.
ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE
EXHAUST GAS OXYGEN (EGO) SENSOR
With engine at normal operating temperature, unplug connector from EGO in exhaust manifold. Measure voltage between EGO sensor
terminal and ground. Voltage should increase with increasing engine speed and decrease with decreasing engine speed. Voltage at idle should
fluctuate within a range of .2-.8 volt.
IDLE SW ITCH (1.6L)
Unplug connector from throttle position sensor on throttle body. Connect ohmmeter to switch terminals IDL and ground (Green/Orange and
Blue/Yellow wires on mating connector). Resistance must be less than 5 ohms with throttle in idle position, and more than 10,000 ohms with
throttle pedal depressed.
KNOCK SENSOR (1.6L TURBO)
Disconnect vacuum hose at distributor. Connect timing light. Start engine and record ignition timing. Tap intake plenum with a plastic mallet.
Knock sensor is okay if timing retards. If timing does not retard, check associated circuitry and components. See TIMING CONTROL
SYSTEMS under IGNITION SYSTEM.
NEUTRAL GEAR SWITCH (M/T)
1. Unplug connector near transmission. Place transmission in Neutral. Resistance across switch should be infinite.
2. Place transmission in any other gear. Resistance across switch should be zero ohms. If necessary, replace switch.
Vacuum In. Hg.(1) Voltage
03.84
53.36
102.66
151.93
201.26
25.58
(1)Voltage may vary by plus or minus 15 percent.
Temperature °F (°C)Ohms
-4 (-20)14,600-17,800
68 (20)2200-2700
104 (40)1000-1300
140 (60)500-650
176 (80)290-350
NOTE:A steady voltage higher than .55 volt indicates a continuously rich condition. A steady voltage lower
than .55 volt indicates a continuously lean condition.
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resistance is not within specifications. If injector resistance is okay, check for 12 volts at each injector connector. Repair or replace
connector as necessary.
FUEL INJECTOR RESISTANCE
IDLE CONTROL SYSTEM
Idle Speed Control By-pass Air (ISC-BPA) Valve
1. Remove ISC-BPA valve from engine. Connect a hose from a hot water tap to coolant inlet nipple on ISC-BPA valve. Blow through
valve air port. Note resistance to airflow.
2. Supply hot water at 130°F (56°C) minimum to ISC-BPA valve and allow time for valve to respond. Blow through valve again. If
resistance to airflow does not increase when valve is hot, replace ISC-BPA valve.
3. Apply 12 volts to solenoid terminals. If solenoid does not click, replace ISC-BPA valve.
IGNITION SYSTEM
PICK-UP COIL
Check continuity of pick-up coil. If continuity exists, replace igniter unit. If continuity does not exist, replace pick-up coil.
TIMING CONTROL SYSTEMS
Advance Components (1.3L)
Ignition timing advance is controlled by the ECA.
Advance Components (1.6L Non-Turbo)
Ignition advance is controlled by a centrifugal advance mechanism within the distributor, and by a vacuum advance mechanism. If centrifugal
advance is not within specification, service the distributor. Replace the vacuum advance mechanism if vacuum advance is not within
specification. See IGNITION TIMING
. Also see IGNITION TIMING in ADJUSTMENTS article in the ENGINE PERFORMANCE Section.
IGNITION TIMING
Retard Components (1.6L Turbo)
Positive pressure to the vacuum advance cylinder on the distributor retards ignition timing. The ECA also retards ignition timing when it
receives a signal from a Knock Sensor (KS), Knock Control Unit (KC) and related circuitry.
1. Disconnect and plug hoses at distributor. Connect timing light and start engine. Record ignition timing. Tap intake plenum with plastic
mallet while observing ignition timing. If timing retards, knock control circuitry is okay. If timing does not retard, go to step 2).
2. Unplug KC sensor service connector near ECA. Tap intake plenum with plastic mallet while observing ignition timing. If ignition timing
retards, go to step 3). If timing does not retard, go to step 4).
3. Reconnect KC service connector. Tap intake plenum with plastic mallet while observing ignition timing. If ignition timing retards,
replace knock controller. If ignition timing does not retard, go to step 4).
4. Unplug KC service connector near ECA. Temporarily install a known good KS. Tap intake plenum with plastic mallet while observing
ignition timing. If ignition timing retards, replace KS. If ignition timing does not retard, go to step 5).
5. Turn ignition off. Connect BOB. Ensure VPWR and ground wires to KC are okay. Check all KC wiring for shorts or opens. If wiring is
okay, replace KC.
EMISSION SYSTEMS & SUB-SYSTEMS
FUEL EVAPORATION
Canister Purge Solenoid
1. Disconnect vacuum hoses from solenoid. See Fig. 1 . Blow through port "A". Ensure no air exhausts from port "B".
2. Disconnect 2-wire connector from solenoid. Connect 12 volts to one terminal and ground the other terminal of solenoid. Blow air
though port "A". Ensure air exhausts through port "B".
ApplicationOhms
1.3L & 1.6L12-16
NOTE:For basic ignition checks, see BASIC T EST ING article in the ENGINE PERFORMANCE Section.
ApplicationAuto. Trans.Man. Trans.
1.6L Non-Turbo1-3 @ 8500-4 @ 850
1.6L Turbo10-14 @ 8500-4 @ 850
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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.
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G - T EST S W/CODES
1991-92 ENGINE PERFORMANCE Ford Motor Co. Self-Diagnostics
INTRODUCTION
If no faults were found while performing BASIC TESTING , proceed with self-diagnostics. If no fault codes or only pass codes are present
after entering self-diagnostics, proceed to TESTS W/O CODES article in the ENGINE PERFORMANCE Section for diagnosis by symptom
(i.e., ROUGH IDLE, NO START, etc.).
This article uses many abbreviations for devices, signal names, and wire colors. See SELF
-DIAGNOSTICS ABBREVIATIONS table.
Abbreviations for wire colors used in individual PINPOINT TEST diagrams are as follows:
BLK - Black
BLU - Blue
BRN - Brown
GRN - Green
LT GRN - Light Green
ORG - Orange
PNK - Pink
RED - Red
WHT - White
YEL - Yellow
SELF-DIAGNOSTICS ABBREVIATIONS
SELF-DIAGNOSTIC SYSTEM
Hard Failures
Hard failures cause CHECK ENGINE light (MIL) to come on and remain on until problem is repaired. If MIL comes on and remains on (light
may flash) during vehicle operation, cause of malfunction must be determined using diagnostic (code) charts. If a sensor fails, ECA will use a
substitute value in its calculations to permit continued engine operation. In this condition (limp-in mode), vehicle will run but driveability will
not be optimum.
Intermittent Failures
Intermittent failures may cause MIL to flicker or come on and go off after intermittent defect goes away. Corresponding trouble code, however,
will be retained in ECA memory. If related defect does not reoccur within a certain time frame, related trouble code will be erased from ECA
ApplicationAbbreviation
Analog Volt/OhmmeterVOM
Barometric Pressure SensorBP
Breakout BoxBOB
Canister Purge Control SolenoidCANP
CHECK ENGINE LightMIL
Crankshaft Position SensorCPS
Cylinder Identification SensorCID
Electronic Control AssemblyECA
Electronic Engine ControlEEC
Engine Coolant Temperature SensorECT
Exhaust Gas Oxygen SensorEGO
Idle Speed ControlISC
Ignition Diagnostic MonitorIDM
Keep Alive PowerKAPWR
Key On Engine OffKOEO
Key On Engine RunningKOER
Knock ControlKC
Power & Ground ConnectionsPGC
Fuel Pressure Regulator Control SolenoidPRC
Reference Voltage & Signal ReturnVREF
Self-Test InputSTI
Self-Test OutputSTO
Signal ReturnSIGRTN
Solenoid Controlled By GroundSCG
Switch Monitor LampSML
Switch To GroundSTG
Switch To PowerSTP
Throttle Position SensorTP
Vane Airflow MeterVAF
Vane Air Temperature SensorVAT
Vehicle PowerVPWR
Vehicle Speed SensorVSS
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memory. Intermittent failures may be caused by a sensor, connector, or wiring. See INTERMITTENTS in TESTS W/O CODES article in the
ENGINE PERFORMANCE Section.
VISUAL CHECK & VEHICLE PREPARATION
Before connecting any equipment to diagnose EEC system, perform following preparatory procedures:
Verify condition of air cleaner and air ducts.
Check all vacuum hoses for leaks, restrictions, or improper routing.
Check EEC system wiring harness electrical connections for corrosion, bent or broken pins, loose wires or terminals, or improper
routing.
Check ECA, sensors, and actuators for physical damage.
Check engine oil and coolant level.
Perform all necessary safety precautions to prevent personal injury or vehicle damage.
Set parking brake. Place shift lever in Park for automatic transmissions, or Neutral for manual transmissions. DO NOT move shift lever
during test unless specifically directed.
Turn off all lights and accessories. Ensure vehicle doors are closed when measuring voltage or resistance.
Start engine. Run at idle until upper radiator hose is hot and pressurized and engine is off fast idle. Check for leaks around exhaust
manifold, exhaust gas oxygen sensor, and vacuum hose connections.
Turn ignition off. Service items as required. Go to EQUIPMENT HOOK-UP .
EQUIPMENT HOOK-UP
VOM
1. Turn ignition off. Connect a jumper wire from STI connector to ground. Refer to SELF-TEST CONNECTOR LOCATION and
SELF
-TEST CONNECTOR WIRE COLORS tables. See Fig. 1 .
2. Connect VOM between STO terminal and engine ground. Set VOM to measure 0-20 volts DC.
CHECK ENGINE Light (MIL)
Connect a jumper wire between STI connector and ground.
SUPER STAR II Tester
Turn ignition off. Connect adapter cable leads to diagnostic tester. Connect service adapter cables to vehicle self-test connectors. Ground
adapter cable.
SELF-TEST CONNECTOR LOCATION
SELF-TEST CONNECTOR WIRE COLORS

Fig. 1: Self
-Test Connector Terminal ID
Courtesy of FORD MOTOR CO.
RETRIEVING CODES
Reading Service Codes
ApplicationLocation
1.3LLeft Rear Corner Of Engine Compartment
1.6LRight Rear Corner Of Engine Compartment
CircuitWire Color
1.3L
SMLBlue/Green
STIYellow/Green
STOYellow/White
1.6L
SMLBlack/Blue
STIYellow
STOGreen/Black
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