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DO NOT expose the ABS control unit to prolonged periods of high heat (185°F/85°C for 2 hours is
generally considered a maximum limit).
BLEEDING BRAKE SYSTEM
For ABS hydraulic unit bleeding, see HYDRAULIC UNIT under REMOVAL & INSTALLATION.
BRAKE LINE BLEEDING SEQUENCE
(1)
DIAGNOSIS
ABS system can only be diagnosed using ABS Tester (0000-42-0010). See Fig. 13 . An Adapter Harness
(49N0-66-001) is also required to test Miata ABS system. ABS tester cannot diagnose ABS control unit. If a
malfunction is detected in ABS and all other components in brake system are okay, replace ABS control unit.
If ABS tester is unavailable, test each component of ABS. See test procedures under TESTING. If all ABS
components test okay, replace control unit with a known good unit, and retest system for correct operation.
PRE-DIAGNOSIS INSPECTION
Perform a visual inspection of ABS components that could cause anti-lock problem. Visual inspection may help
identify cause of simple problem.
DIAGNOSTIC PROCEDURE WITH ABS TESTER
ABS tester uses one display window and 2 switches for reading information from unit. Become thoroughly
familiar with ABS tester displays and operation before proceeding. See Fig. 13
. To diagnose ABS system, go
to TESTING SEQUENCE charts under DIAGNOSING ABS SYSTEM. When diagnosing ABS system,
complete tests in order given under TESTING SEQUENCE. If ABS tester does not operate, check fuses,
ignition switch and ignition circuit.
TESTING
NOTE: See BRAKE BLEEDING article in the BRAKES Section.
ApplicationSequence
Miata & 929Longest Line First
RX7RR, LR, RF, LF
(1)If rear caliper has not been disassembled, open upper bleed valve only.
NOTE: Before testing ABS components, ensure battery and charging system are
functioning properly. To prevent damage to ABS control unit connector, use
very thin pins when probing connector.
1991 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1988-91 BRAKES Mazda Anti-Lock Brake System
Microsoft
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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
Microsoft
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Microsoft
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Page 246 of 392

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
Microsoft
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Page 247 of 392

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
Microsoft
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