1991 MAZDA MIATA alternator belt

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
Sunday, July 05, 2009 2:14:53 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.
Microsoft
Sunday, July 05, 2009 2:14:58 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.

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
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
Microsoft
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
Microsoft
Sunday, July 05, 2009 2:14:54 PMPage 4 © 2005 Mitchell Repair Information Company, LLC.

1990-93 ENGINE COOLING
Drive Belt Routing & Adjustment - MX-5 Miata
ADJUSTMENT
Fig. 1: Identifying Correct Belt Mounting
Courtesy of MAZDA MOTORS CORP.
ALTERNATOR
Loosen alternator bolts and adjust belt deflection by turning adjusting bolt. See Fig. 2
, Fig. 6 and Fig. 7 . See
ADJUSTMENT SPECIFICATIONS
. Tighten bolts to specification. See TORQUE SPECIFICATIONS. NOTE: Ensure drive belts are not worn, cracked or frayed and are correctly mounted
on pulleys. See Fig. 1
.
NOTE: If a new belt is used, adjust belt deflection at midpoint of new belt specification.

1991 Mazda MX-5 Miata
1990-93 ENGINE COOLING Drive Belt Routing & Adjustment - MX-5 Miata

1991 Mazda MX-5 Miata
1990-93 ENGINE COOLING Drive Belt Routing & Adjustment - MX-5 Miata
Microsoft
Sunday, July 05, 2009 2:14:16 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.
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Sunday, July 05, 2009 2:14:28 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.

Fig. 2: Adjusting Alternator Belt
Courtesy of MAZDA MOTORS CORP.
A/C COMPRESSOR
Loosen locknut and adjust belt deflection by turning adjusting bolt. See Fig. 3
, Fig. 6 and Fig. 7 . See
ADJUSTMENT SPECIFICATIONS
. Tighten bolts to specification. See TORQUE SPECIFICATIONS.

1991 Mazda MX-5 Miata
1990-93 ENGINE COOLING Drive Belt Routing & Adjustment - MX-5 Miata
Microsoft
Sunday, July 05, 2009 2:14:16 PMPage 2 © 2005 Mitchell Repair Information Company, LLC.

Fig. 7: Identifying Drive Belt Routing & Deflection Check Point (3 Of 3)
Courtesy of MAZDA MOTORS CORP.
ADJUSTMENT SPECIFICATIONS
DEFLECTION SPECIFICATIONS
NOTE: Check belt deflection when engine is cold, or has bin off for 30 minutes.
Application(1) Specification - In. (mm)
New Belt (2)
Alternator0.31-0.35 (8-9)
A/C Compressor0.31-0.35 (8-9)
Power Steering Pump0.31-0.35 (8-9)
Used Belt
Alternator0.35-0.39 (9-10)
A/C Compressor0.35-0.39 (9-10)
Power Steering Pump0.35-0.39 (9-10)
(1)Deflection with 22 lbs. (10 kg) pressure applied midway on belt run.
Used on for less than 5 minutes.

1991 Mazda MX-5 Miata
1990-93 ENGINE COOLING Drive Belt Routing & Adjustment - MX-5 Miata
Microsoft
Sunday, July 05, 2009 2:14:16 PMPage 7 © 2005 Mitchell Repair Information Company, LLC.

TENSION SPECIFICATIONS
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS
(2)
Application(1) Specification - Lbs. (kg)
New Belt (2)
Alternator110-132 (50-60)
A/C Compressor110-132 (50-60)
Power Steering Pump110-132 (50-60)
Used Belt
Alternator95-110 (43-50)
A/C Compressor95-110 (43-50)
Power Steering Pump95-110 (43-50)
(1)Measure tension using Tension Gauge (49 9200 020), or equivalent.
(2)Used on for less than 5 minutes.
ApplicationFt. Lbs. (N.m)
Alternator Adjusting Bolt
"A"14-18 (19-25)
"B"27-38 (37-52)
A/C Compressor Locknut27-38 (37-52)
Power Steering Pump Adjusting Bolt
"A"23-44 (31-46)
"B"27-40 (37-54)
"C"14-18 (19-25)

1991 Mazda MX-5 Miata
1990-93 ENGINE COOLING Drive Belt Routing & Adjustment - MX-5 Miata
Microsoft
Sunday, July 05, 2009 2:14:16 PMPage 8 © 2005 Mitchell Repair Information Company, LLC.