1991 FORD FESTIVA Ignition switch

IDLE SPEED & MIXTURE
IDLE MIXTURE
IDLE SPEED
1. Turn off all accessories. Place automatic transmission in Park or manual transmission in Neutral. Set parking brake. Connect tachometer
to engine. Warm engine to normal operating temperature. Connect a jumper wire between single-wire STI test connector (Green on
Capri; Black on Festiva) and ground. See Fig. 1
.
2. Locate idle speed control by-pass air (ISC-BPA) valve on intake manifold. Remove cap, and adjust idle speed to specification by turning
idle air adjust screw on ISC-BPA valve. See Fig. 2
. Remove jumper wire.
IDLE RPM

Fig. 2: Locating Idle Air Adjust Screw

Courtesy of FORD MOTOR CO.
THROTTLE POSITION SWITCH (TP)
CAPRI
Throttle position sensor is preset at factory. No adjustment is required.
FESTIVA
1. Ensure idle speed and ignition timing are adjusted to specification. Stop engine. Disconnect negative battery cable.
2. Unplug TP connector at throttle body. Insert appropriate feeler gauge between throttle stop screw and stop lever. Check for continuity
between specified terminals on TP connector. See TP ADJUSTMENT table.
3. To adjust, loosen TP attaching screws. Connect ohmmeter between terminals IDL and TL. See Fig. 3
. Insert a .020" (.5 mm) feeler
gauge between throttle stop screw and stop lever.
4. Rotate TP until ohmmeter indicates continuity. Insert a .028" (.7 mm) thickness gauge between stop screw and stop lever. Ohmmeter
should indicate no continuity. If ohmmeter indicates continuity, repeat adjustment procedure.
ApplicationAuto. Trans.Man. Trans.
1.3L9-11 @ 8509-11 @ 700
1.6L Non-Turbo1-3 @ 8500-4 @ 850
1.6L Turbo10-14 @ 8500-4 @ 850
NOTE:Idle m ixture is controlled by ECA and is not adjustable.
ApplicationAuto. Trans.Man. Trans.
1.3L830-870680-720
1.6L800-900800-900
CAUT ION: DO NOT tam per with throttle stop screw at throttle lever. Doing so m ay result in dam age to throttle
body.
Page 2 of 3 MITCHELL 1 ARTICLE - D - ADJUSTMENTS 1991 ENGINE PERFORMANCE Ford/Mercury - On-Vehicle Adjustments
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K - SENSOR RANGE CHART S
1991 ENGINE PERFORMANCE Ford Motor Co. Sensor Operating Range Charts
INTRODUCTION
Sensor operating range information can help determine if a sensor is out of calibration. An out-of-calibration sensor may not set a trouble
code, but it may cause driveability problems.
BAROMETRIC PRESSURE SENSOR OUTPUT VOLTAGE
ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE
IGNITION DIAGNOSTIC MONITOR VOLTAGE
THROTTLE POSITION SENSOR RESISTANCE
(1)
VANE AIRFLOW METER VOLTAGE NOTE:Unless stated otherwise in test procedure, perform all voltage tests using a Digital Volt-Ohm m eter
(DVOM) with a m inim um 10-m egohm input im pedance.
Vacuum In. Hg.(1) Volts
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
RPM (1) Volts
5001.103
10001.257
15001.542
20001.768
25002.06
30002.15
35002.26
40002.50
45002.47
50002.40
(1)Revolutions per minute.
Throttle Opening(2) Ohms
1/8989
1/41104
3/81278
1/21462
5/81480
3/41459
7/81144
Fully Open1072
(1)Capri only. Festiva uses throttle position switch.
(2)Resistance may vary by plus or minus 15 percent.
Door Opening(1) Volts (Capri)(1) Volts (Festiva)
Fully Closed(2) .5-1.5
1/83.24.59
1/45.601.19
3/85.621.78
1/25.832.38
5/86.022.97
3/46.573.56
7/87.464.16
Fully Open7.874.5-5.0
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F - BASIC TESTING
1991-92 ENGINE PERFORMANCE Ford Motor Co. Basic Diagnostic Procedures
INTRODUCTION
The following diagnostic steps help prevent overlooking simple problems and begin diagnosis for a no-start condition.
The first step in diagnosing any driveability problem is to verify the complaint. Test drive the vehicle under the conditions in which the
problem reportedly occurred.
Before entering self-diagnostics, perform a careful and complete visual inspection. Most engine control problems result from mechanical
breakdowns, poor electrical connections or damaged/misrouted vacuum hoses. Before condemning the computerized system, perform each test
listed in this article.
PRELIMINARY INSPECTION & ADJUSTMENTS
VISUAL INSPECTION
Perform a visual inspection of all electrical wiring. Look for chafed, stretched, cut or pinched wiring. Ensure electrical connections fit tightly
and are not corroded. Ensure vacuum hoses are properly routed and are not cut or pinched. If necessary, see VACUUM DIAGRAMS article in
the ENGINE PERFORMANCE Section to verify routing and connections. Inspect air induction system for possible vacuum leaks.
MECHANICAL INSPECTION
Compression
Engine mechanical condition can be checked using a compression gauge, vacuum gauge or engine analyzer. See engine analyzer instruction
manual for specific instructions. Lowest compression reading must be not less than 75 percent of highest reading.
Exhaust System Backpressure
Exhaust system can be checked with a vacuum gauge or a 0-5 psi pressure gauge. If a pressure gauge is used, remove O2 sensor. Connect gauge
to O2 sensor port. Start engine, and run at 2500 RPM. If exhaust system backpressure is more than 2 psi, exhaust system or catalytic converter
is plugged.
If a vacuum gauge is used, connect it to intake manifold vacuum. Start engine. Observe vacuum gauge. Open throttle part way and hold steady.
If vacuum gauge drops slowly after stabilizing, check exhaust system for a restriction.
FUEL PRESSURE
Fuel Pressure Release
Start engine (if possible), and unplug VAF meter connector. When engine stalls, turn ignition off and reconnect VAF meter wiring. Usin g sh o p
towel, cover fitting to absorb leakage when opening fuel system.
Fuel Pressure Check
1. Connect fuel pressure gauge between fuel filter and fuel rail. Open main valve, and close drain valve. Locate fuel pump check connector
in engine compartment, near left strut. Connect jumper wire between fuel pump test terminals (Black and Green/White wires on Capri
or Black and Green/Red wires on Festiva).
2. Turn ignition on to activate fuel pump. If pump does not run, check fuel pump circuit. If possible, start engine. Measure and record fuel
pressure. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS
article. Disconnect vacuum from pressure
regulator. Turn engine off. Wait 5 minutes and ensure residual pressure is at least 21 psi (1.5 kg/cm
2 ).
3. Operate fuel pump by reconnecting jumper wire at fuel pump check connector. Check fuel pump performance. Pinch hose between
pressure gauge and fuel filter. Do not hold longer than necessary to check pressure.For fuel pressure specifications, see FUEL
PRESSURE SPECIFICATIONS article. If pump does not meet specifications, check fuel pump circuit, fuel pump, fuel tank and fuel
filter or replace fuel pump.
FUEL PUMP PERFORMANCE NOTE:Unless stated otherwise in test procedure, perform all voltage tests with a Digital Volt-Ohm m eter
(DVOM) with a m inim um 10-m egohm input im pedance.
CAUT ION: DO NOT use ignition switch during com pression tests on fuel injected vehicles. Fuel injectors are
triggered by ignition switch during cranking m ode. Use a rem ote starter to crank engine to prevent fire
hazard and catalytic converter and engine oiling system contam ination.
WARNING:ALWAYS relieve fuel pressure before disconnecting any fuel injection system com ponent. DO NOT
allow fuel to contact engine or electrical com ponents.
NOTE:For 1991 fuel pressure specifications, see FUEL PRESSURE SPECIFICAT IONS
article. For 1992 fuel
pressure specifications, see FUEL PRESSURE SPECIFICAT IONS
article.
ApplicationPressure psi (kg/cm2 )Min. Vol. in 10 sec. Ozs. (cc)
Capri(1) 5.5 (167)
Festiva(1) 7.4 (220)
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Fuel Pump Circuit
1. Turn ignition on. Connect jumper wire between fuel pump test connector terminals. See Fig. 1 or Fig. 2 . Turn ignition on to activate
fuel pump.
2. Listen for fuel pump sound. If there is no sound, check main fuse, inertia switch (located at left rear shock tower), fuel pump rel ay, fu el
pump and all electrical connections.

Fig. 1: Festiva Fuel System Electrical Schematic

Courtesy of FORD MOTOR CO.
(1)For 1991 fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. For 1992 fuel pressure specifications,
see FUEL PRESSURE SPECIFICATIONS
article.
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Fig. 2: Capri Fuel System Electrical Schematic
Courtesy of FORD MOTOR CO.
Fuel Pump Relay
Remove fuel pump relay (located near heater duct under carpet). Apply positive 12 volts to relay terminals "A" and "B" together. See Fig. 3 .
Measure voltage between terminal "C" and ground, while individually grounding terminals "D" and "E". Ensure voltage is as specified. See
FUEL PUMP RELAY SPECIFICATIONS
table. If voltage is not as specified, replace relay.
FUEL PUMP RELAY SPECIFICATIONS

Fig. 3: Identifying Fuel Pump Relay Terminals

Courtesy of FORD MOTOR CO.
IGNITION CHECKS
Firing Order
Inspect spark plug wiring routing. Ensure firing order is 1-3-4-2.
Spark
1. Crank engine. Check for a strong Blue spark at each spark plug wire by using a high output spark tester. Ensure resistance of each spark
plug wire is 4000-6000 ohms per foot.
2. Disconnect and inspect all related ignition system connectors and harness. Clean or repair as necessary, and recheck spark. If st il l n o
spark, go to IGNITION COIL POWER SOURCE
.
Ignition Coil Power Source
Disconnect primary wires at ignition coil. Turn ignition on. Measure voltage between Black/White wire on harness connector and ground. If
voltage is not greater than 10 volts, check battery feed, ignition switch and fusible links. If voltage is greater than 10 volts, go to IGNITION
COIL RESISTANCE .
Ignition Coil Resistance
Measure resistance between primary terminals of coil. Measure resistance between positive primary terminal and coil tower. See IGNITION
COIL RESISTANCE table. Verify resistance between coil case and primary positive terminal is infinite. Replace coil if resistance
measurements are not within specifications.
IGNITION COIL RESISTANCE
IDLE SPEED & IGNITION TIMING
Ensure idle speed and ignition timing are set to specification. For adjustment procedures, see ON-VEHICLE ADJUSTMENTS article.
SUMMARY
If no faults were found while performing BASIC TESTING , proceed to TESTS W/CODES article in the ENGINE PERFORMANCE Section.
If no hard codes are found in 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.) or intermittent diagnostic procedures.
Terminal "D"Terminal "E"Terminal "C" Voltage
OpenOpenLess than one
GroundedOpenLess than 10
OpenGroundedGreater than 10
GroundedGroundedGreater than 10
ApplicationPrimary (Ohms)Secondary (Ohms)
1.3L & 1.6L0.8-1.66000-30,000
Copyr ight 2009 Mitchell Repair Information Company, LLC. All Rights Reserved.
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I - SYST EM/COMPONENT T EST S
1991 ENGINE PERFORMANCE Ford Motor Co. - Ford/Mercury System & Com ponent T esting
INTRODUCTION
Before testing separate components or systems, perform procedures in BASIC TESTING article in the ENGINE PERFORMANCE Section.
Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in TESTS
W/CODES article in the ENGINE PERFORMANCE Section.
AIR INDUCTION SYSTEMS
TURBOCHARGERS
Wastegate Actuator
Disconnect air hose from wastegate actuator. Apply 7.0-8.6 psi (.5-.6 kg/cm2 ) regulated air pressure to wastegate inlet fitting. Replace
turbocharger if wastegate actuator rod does not move.
COMPUTERIZED ENGINE CONTROLS
ELECTRONIC CONTROL ASSEMBLY (ECA)
Ground Circuits
Turn ignition off. Connect BOB, leaving ECA disconnected. Measure resistance between each specified BOB pin and ground. See ECA
GROUND CIRCUIT RESISTANCE table. Repair indicated ECA ground circuit if resistance is greater than 5 ohms.
ECA GROUND CIRCUIT RESISTANCE
Power Circuits
Turn ignition off. Connect BOB, leaving ECA disconnected. Turn ignition on. Repair indicated ECA power circuit if battery voltage d o e s n o t
appear on specified BOB pin. See ECA POWER CIRCUITS RESISTANCE
.
ECA POWER CIRCUIT RESISTANCE
ENGINE SENSORS & SWITCHES
Check each component and all related wiring for any looseness or damage. Make all resistance and voltage measurements using Breakout Box
(BOB) unless specified otherwise.
BAROMETRIC PRESSURE SENSOR (1.3L)
This unit is incorporated into the ECA, and cannot be checked or serviced separately. If a Code 14 is set and cannot be cleared, replace the
ECA.
BAROMETRIC PRESSURE (BP) SENSOR (1.6L) NOTE:T esting individual com ponents does not isolate shorts or opens. Perform all voltage tests with a Digital
Volt-Ohm m eter (DVOM) with a m inim um 10-m egohm input im pedance, unless stated otherwise in test
procedure. Use ohm m eter and Breakout Box (BOB) (007-00033) to isolate wiring harness shorts or
opens.
ECA PinBOB PinWire Color
1.3L
2A39,40,44Black
2B20Black
2C16Black
2D46,49Black
2J (2) (3) 6(3) White/Red
2J (4) 6Black
1.6L
2R49Black
3A (1) (1) 20Black
3G (1) (1) 40Black
(1)Turbo only.
(2)A/T models only.
(3)No continuity on A/T models.
(4)M/T models only.
ECA PinBOB PinWire Color
1.3L: 1A1White/Red
1.6L: 3J1Black/Red
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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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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.
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