electrical MAZDA MIATA 1991 Factory Service Manual

OPERATION
Under normal driving conditions, the anti-lock brake system functions as a standard brake system. When
vehicle speed reaches 3.8 MPH, the ABS system will diagnose pump motor by briefly operating motor. Pump
motor operation may be heard inside vehicle.
The Electronic Control Unit (ECU) controls ABS by detecting speed sensor signals and activating solenoid
valve in hydraulic unit. Control unit also controls pump motor and self-diagnostic function. If a problem in the
ABS system is detected, ABS system functions as a conventional brake system. The ANTI-LOCK brake
warning light will also come on.
With detection of wheel lock-up, short pedal pulsations, occurring in rapid succession, will be felt in brake
pedal and steering wheel. Vehicle body may also vibrate slightly. These conditions are normal. Pedal pulsation
will continue until there is no longer a need for anti-lock function or until vehicle is stopped.
ANTI-LOCK BRAKE SAFETY PRECAUTIONS
NEVER open a bleeder valve or loosen a hydraulic line while ABS is pressurized.
NEVER disconnect or reconnect any electrical connectors while ignition is on. Damage to ABS control
unit may result.
DO NOT attempt to bleed hydraulic system without first referring to the appropriate article.
Only use specially designed brake hoses/lines on ABS-equipped vehicles.
DO NOT tap on speed sensor components (sensor, sensor rings). Speed rings must be pressed, NOT
hammered into hubs. Striking these components can cause demagnetization or a loss of polarization,
affecting the accuracy of the speed signal returning to the ABS control unit.
DO NOT mix tire sizes. Increasing the width, as long as tires remain close to the original diameter, is
acceptable. Rolling diameter must be identical for all 4 tires. Some manufacturers recommend tires of the
same brand, style and type. Failure to follow this precaution may cause inaccurate wheel speed readings.
DO NOT contaminate speed sensor components with grease. Only use recommended anti-corrosion
coating.
When speed sensor components have been removed, ALWAYS check sensor-to-ring air gaps when
applicable. These specifications can be found in each appropriate article.
ONLY use recommended brake fluids. DO NOT use silicone brake fluids in an ABS-equipped vehicle.
When installing transmitting devices (CB's, telephones, etc.) on ABS-equipped vehicles, DO NOT locate
the antenna near the ABS control unit (or any control unit).
Disconnect all on-board computers, when using electric welding equipment. CAUTION: See ANTI-LOCK BRAKE SAFETY PRECAUTIONS below.
WARNING:Refer to appropriate Anti-Lock Brakes (ABS) article for description,
operation, depressurizing, testing, system bleeding, trouble shooting and
system service. Failure to depressurize ABS could lead to physical injury.

1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
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2. Release parking brake lever. Using a screwdriver, reach through parking brake handle hole in console and
rotate adjusting screw until stroke is 6-8 notches. Ensure rear wheels rotate freely. Ensure parking brake
warning light illuminates when brake lever is pulled one notch.
Miata, MX-6, MPV, Protege, RX7, 323, 626
1. On models with rear disc brakes, depress brake pedal several times. On models with rear drum brakes,
start engine and depress brake pedal several times while vehicle is moving in Reverse. Stop engine.
2. On all models, pull parking brake lever with a force of 22 lbs. (10 kg). If stroke is 5-7 notches, parking
brake is properly adjusted. If stroke is not 5-7 notches, raise and support rear of vehicle. Release parking
brake lever.
3. Rotate cable adjusting nut at lever end of cable (under console cover) until stroke is within specification.
On models equipped with rear disc brakes, ensure clearance between stopper and lever (at each caliper) is
not less than .08" (2 mm) on RX7, or zero on all other models. On all models, ensure parking brake
warning light illuminates when brake lever is pulled one notch.
PARKING BRAKE SHOES
929
Raise and support vehicle. Remove rear wheels. Remove service plug from rotor. Using a screwdriver, rotate
star wheel adjuster toward axle until rotor locks. Rotate adjuster in opposite direction 3-5 notches. Ensure rotors
turn freely and parking brake functions properly. Install service plug and rear wheels.
PEDAL FREE PLAY
Depress pedal a few times to eliminate vacuum. Pedal free play should be .16-.28" (4-7 mm). Adjust play by
loosening push rod lock nut. Turn push rod until correct free play is obtained. Tighten push rod lock nut.
PEDAL HEIGHT & STOPLIGHT SWITCH
1. Released pedal height is measured from carpet surface on vertical portion of firewall to pedal pad center.
Disconnect stoplight switch electrical connector. Loosen lock nut on stoplight switch. Move switch away
from pedal. Loosen push rod lock nut. Turn rod until correct pedal height is obtained. See BRAKE
PEDAL HEIGHT SPECIFICATIONS .
2. Adjust pedal free play. See PEDAL FREE PLAY
under ADJUSTMENTS. Tighten push rod lock nut.
Rotate stoplight switch until it contacts pedal and then rotate an additional 1/2 turn. Tighten stoplight
switch lock nut. Reconnect stoplight switch electrical connector.
3. Applied pedal height is measured from angled portion of firewall (without carpet) to pedal pad center.
Start engine. On B2200, B2600i and MPV, depress brake pedal with 33 lbs. (15 kg) pressure. On all other
models, depress brake pedal with 132 lbs. (60 k
g) pressure. tension should be checked and adjusted.
NOTE: Pedal height and stoplight switch information is not available for Navajo.

1991 Mazda MX-5 Miata
BRAKE SYSTEM 1991 BRAKES Mazda Brake System
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ALTERNATOR & REGULATOR
1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
DESCRIPTION
Alternators are conventional 3-phase, self-rectifying type units containing 6 diodes (3 positive and 3 negative)
which are used to rectify current. See Fig. 1
. An internally-mounted, Integrated Circuit (IC) regulator is used
on all models.
Fig. 1: Charging System Wiring Schematic

Courtesy of MAZDA MOTORS CORP.
ADJUSTMENTS
BELT DEFLECTION
Measure belt deflection in center of longest pulley-to-pulley span. See BELT DEFLECTION
SPECIFICATIONS table. If belt deflection is not as specified, adjust as necessary.
BELT DEFLECTION SPECIFICATIONS
ApplicationDeflection - In. (mm)

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
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Sunday, July 05, 2009 2:14:53 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.
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TROUBLE SHOOTING
CHARGING SYSTEM
B2200
New Belt0.28-0.31 (7.0-8.0)
Used Belt0.31-0.35 (8.0-9.0)
B2600i
New Belt0.39-0.47 (10.0-12.0)
Used Belt0.43-0.51 (11.0-13.0)
Miata
New Belt0.31-0.35 (8.0-9.0)
Used Belt0.35-0.39 (9.0-10.0)
MPV
4-Cylinder Engine
New Belt0.39-0.47 (10-12)
Used Belt0.43-0.57 (11-13)
V6 Engine
New Belt0.35-0.39 (9-10)
Used Belt0.39-0.47 (10-12)
MX-3
4-Cylinder Engine
New Belt0.31-0.35 (8.0-9.0)
Used Belt0.35-0.39 (9.0-10.0)
V6 Engine
New Belt0.24-0.28 (6.0-7.0)
Used Belt0.28-0.31 (7.0-8.0)
MX-6 & 626
New Belt0.24-0.31 (6.0-8.0)
Used Belt0.28-0.35 (7.0-9.0)
Protege & 323
New Belt0.31-0.35 (8.0-9.0)
Used Belt0.35-0.39 (9.0-10.0)
RX7
New Belt0.47-0.59 (12.0-15.0)
Used Belt0.55-0.67 (14.0-17.0)
929
New Belt0.35-0.39 (9.0-10.0)
Used Belt0.39-0.47 (10.0-12.0)
- With 22 lbs. (98N) applied to belt.

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
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Sunday, July 05, 2009 2:14:54 PMPage 2 © 2005 Mitchell Repair Information Company, LLC.

CHARGING SYSTEM TROUBLE SHOOTING
TROUBLE SHOOTING PRECAUTIONS
Miata
Obtain code number and deactivate audio anti-theft system before disconnecting battery.
All Models
DO NOT reverse battery cable connections. Rectifier will be damaged.
DO NOT use high voltage type testers.
PROBLEM Possible CauseAction
NO START CONDITION
Dead BatteryCheck/Replace Battery
Bad Cable ConnectionsClean/Replace Cables
Ignition Switch/Circuit FaultCheck Switch/Circuit
CHARGING SYSTEM WARNING LIGHT STAYS ON
Loose/Worn Alternator BeltTighten/Replace Belt
Loose Alternator ConnectionsCheck/Repair
Connections
Warning Light WiringCheck/Repair Wiring
Faulty Stator/DiodesTest/Repair Alternator
Faulty Voltage RegulatorTest/Repair Regulator
WARNING LIGHT OFF WITH IGNITION SWITCH ON
Blown FuseCheck/Replace Fuse
Faulty AlternatorTest Alternator
Bad Warning Light BulbTest/Replace Bulb
WARNING LIGHT ON WITH IGNITION SWITCH OFF
Alternator Wiring ShortCheck/Repair Wiring
Faulty Rectifier BridgeTest/Repair Alternator
AMMETER INDICATES DISCHARGE
Loose/Worn Alternator BeltTighten/Replace Belt
Loose Alternator ConnectionsCheck/Repair
Connections
Faulty AmmeterTest/Replace Ammeter
NOISY Defective BatteryReplace Battery
Defective AlternatorTest/Repair Alternator
Defective RegulatorTest/Repair Regulator
NOTE: Observe the following precautions when trouble shooting or testing charging
system:

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
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Sunday, July 05, 2009 2:14:54 PMPage 3 © 2005 Mitchell Repair Information Company, LLC.

Battery voltage is always applied to terminal "B".
DO NOT ground terminal "L" while engine is running.
DO NOT start engine with connector disconnected from terminals "L" and "S".
DO NOT apply battery voltage to terminal "L".
ON-VEHICLE TESTING
ALTERNATOR OUTPUT
1. Connect an ammeter (80-amp minimum) in-line between terminal "B" connector and wire. See Fig. 2
,
Fig. 3
and Fig. 4 . Turn all headlights and accessories on and depress brake pedal. With engine operating
at 2500-3000 RPM, measure output amperage. NOTE: Check alternator wiring harness connections and drive belt tension. Battery
must be fully charged before testing. Wait at least 30 seconds after starting
engine before measuring system voltage.
CAUTION: Ensure alternator terminal "B" does not contact ground.

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
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Sunday, July 05, 2009 2:14:54 PMPage 4 © 2005 Mitchell Repair Information Company, LLC.

Fig. 2: Identifying Alternator Terminals
Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
Microsoft
Sunday, July 05, 2009 2:14:54 PMPage 5 © 2005 Mitchell Repair Information Company, LLC.

Fig. 3: Identifying Alternator Terminals (1992 B2200, B2600i & MPV)
Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
Microsoft
Sunday, July 05, 2009 2:14:54 PMPage 6 © 2005 Mitchell Repair Information Company, LLC.

Fig. 4: Identifying Alternator Terminals (1992 All Other Models)
Courtesy of MAZDA MOTORS CORP.
2. If output amperage is not equal to or more than amount specified in ALTERNATOR OUTPUT table,
repair or replace alternator as necessary.
3. Turn off all accessories and release brake pedal. With engine operating at 2500-3000 RPM, measure
output amperage. If output amperage is not at least 5 amps, repair or replace alternator as necessary.
4. With engine operating at 2500-3000 RPM, measure voltage between terminal "S" and ground. If reading
is not 14.1-14.7 volts, repair or replace alternator as necessar
y.

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
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ALTERNATOR OUTPUT
BENCH TESTING
Rectifier/Diode Assembly
1. Using an ohmmeter, check continuity of each diode in both directions (polarity). See Fig. 5 and Fig. 6. If
diode shows high resistance in one direction and low resistance in other direction, diode is okay.
2. If diode shows low resistance in both directions, it is shorted. If diode shows high resistance in both
directions, diode is open. If an
y diode is defective, replace rectifier assembly.
ApplicationAmps
B220055
B2600i60
Miata
A/T65
M/T60
MPV70
MX-6 & 626
Non-Turbo70
Turbo
A/T80
M/T70
MX-3
4-Cylinder70
V690
Protege & 32365
RX780
92970

1991 Mazda MX-5 Miata
ALTERNATOR & REGULATOR 1990-92 ELECTRICAL Alternators & Regulators - Mitsubishi
Microsoft
Sunday, July 05, 2009 2:14:54 PMPage 8 © 2005 Mitchell Repair Information Company, LLC.