Mazda 121 Workshop Manual Set, 1990–1996 (P/N 1249-10-90J)

The Technical Data and Special Tools sections in Volume 2 support service work across both volumes. The stated vehicle application begins at VIN JMO DB1031 00 100001.

Coverage limits: The supplied files omit the Section K F4A-EL automatic-transaxle repair chapter. They retain F4A-EL specifications and tool references. The separately published Section Z Wiring Diagram, form 5181-10-90J, is also not supplied; individual system wiring and circuit diagrams are included.

PDF Text Search and Circuit Detail

Search, navigation, and small labels: Both PDFs contain OCR text, but recognition errors limit searches, and many wiring labels are absent from the text layer. Neither file has embedded PDF bookmarks. Small labels in the sampled circuit diagrams are readable when enlarged.

The ZIP contains two printable PDFs totaling 771 pages. That total already includes eight supporting pages: both front covers, both foreword/contents pages, both VIN application pages, a memo page in Volume 1, and the back cover in Volume 2.

Engine Overhaul, EGI-S Diagnosis, and Chassis Service

The following selected topics show the repair and diagnostic coverage rather than reproduce the complete contents. Other included examples are headlight aiming and rear-window defroster filament repair.

• Engine and lubrication: Tune-up and compression checks, on-vehicle engine repairs, removal, internal overhaul, oil-pressure testing, and oil-pump service.

• EGI-S and engine electrical: Symptom-based troubleshooting, self-diagnosis, ECU and sensor checks, fuel-pressure testing, and charging, ignition, and starting-system service.

• Manual drivetrain: B5M-R transaxle removal and overhaul, differential and shift-mechanism work, clutch service, and drive-shaft repairs.

• Chassis: Hub and wheel-bearing service, steering diagnosis, brake repairs, wheel alignment, and front and rear suspension work.

• Body and canvas top: Doors, glass, locks, trim, instruments, lighting, wipers, audio, and canvas-top electrical and mechanical repairs.

• Heating and air conditioning: Operating checks, diagnostic flowcharts, component testing, and heater, blower, refrigerant-system, and compressor service.

Mazda wrote this manual for authorized-dealer service technicians and also identifies limited diagnostic, repair, and maintenance uses for owners and operators. It assumes familiarity with automotive systems and basic repair procedures, together with the required special tools and knowledge of their use.

Engine Repair and Scheduled Maintenance

Pre-delivery and scheduled-service tables address valve clearances, drive belts, oil and filters, cooling, ignition, fuel and emissions, clutch and brakes, steering, suspension, drive-shaft boots, and chassis fasteners.

The engine instructions progress from timing-belt, cylinder-head-gasket, and crankshaft oil-seal replacement to engine removal, stand mounting, disassembly, inspection, reassembly, and installation. Internal coverage includes the cylinder head and valve train, camshaft, pistons and connecting rods, crankshaft and bearings, and oil pump.

Step-by-step procedures also cover thermostat and water-pump replacement, radiator-cap inspection, cooling-system checks, and electric cooling-fan diagnosis.

Oil-pan cautions: The manual identifies the joint where prying can damage mating surfaces and warns that old sealant on reused bolts can crack the bolt holes.

B5M-R Transaxle and Clutch Work

Section J explains the manual transaxle’s construction and power flow before its service procedures. Internal work includes gears and shafts, synchronizers, bearings, shift rods and forks, interlock components, and oil seals. Bearing-preload checks and shim selection support reassembly.

The clutch material covers pedal and cable adjustment, cover and disc inspection, release components, the pilot bearing, and flywheel service. Differential inspection and assembly and shift-mechanism overhaul have their own procedures.

EGI-S Fault Isolation

The diagnostic index separates starting faults, unstable idle, stalling under accessory loads, hesitation, surging, power loss, backfire, detonation, fuel or exhaust odors, oil consumption, and poor fuel economy.

Its symptom charts connect inspection results with follow-up tests and corrective actions. This provides a route from a drivability complaint to the relevant ignition, compression, fuel-pressure, sensor, or circuit checks rather than treating each system in isolation.

Component coverage includes the ECU, injectors, crank-angle and airflow sensors, throttle and oxygen sensors, relays, switches, and evaporative-emission equipment. The Mazda Self-Diagnosis Checker and System Selector procedures explain malfunction-code retrieval and related checks. Separate engine-electrical material covers battery condition, alternator, distributor, ignition-coil, and starter testing and service.

Axles, Steering, Brakes, and Suspension

Axle procedures cover front hubs and steering knuckles, rear axles, wheel bearings, and tripod-joint drive shafts. Steering coverage distinguishes manual rack-and-pinion steering from engine-speed-sensing power steering, including hydraulic bleeding and pressure tests.

Brake work includes master-cylinder and booster diagnosis, front discs, rear drums, and parking-brake components. Suspension procedures address struts and springs, lower arms, stabilizers, the rear torsion-beam axle, and trailing-arm bushings, alongside wheel and tire checks and alignment.

Steering-column caution: Mazda warns that hammering the shaft during steering-wheel removal can collapse the column.

Body, Canvas Top, and Climate Systems

Body procedures extend to the hood, doors and window regulators, glass, locks, trunk lid, mirrors, trim, seats, and seat belts. Electrical sections cover instruments, lights, wipers, rear-window defroster, horn, and audio.

The canvas-top section combines circuit diagnosis with switch, motor, limit-switch, and control-unit testing. Mechanical coverage includes guides, rails, frame components, adjustment, and repairs to holes and tears.

Heater and A/C diagnosis uses operating checklists and symptom flowcharts. Service material covers heater and blower units, the cooling unit, condenser, receiver/drier, pressure switch, magnetic clutch, and compressor. The refrigerant procedures describe the original R-12 system.

Diagrams, Specifications, and Workshop Equipment

Illustrations include the EGI-S system diagram, vacuum-hose-routing diagram, B5M-R power-flow view, starting-system circuit, canvas-top circuit, and A/C connector-location views and diagnostic flowcharts.

Technical Data tables supply torque specifications, fluid requirements, clearances, wear limits, adjustment data, and electrical test values. Numbered Mazda SST listings include the 49 0107 680A engine stand, 49 9200 020 V-ribbed-belt tension gauge, and 49 SE01 310A clutch centering tool, plus equipment for transaxle, brake, axle, steering, suspension, diagnostic, and A/C work.

Brake hydraulics, fuel-pressure work, steering, compressed springs, and refrigerant service require appropriate equipment and safe workshop practices. Work beyond your training or available tooling should be handled by a qualified automotive technician.

A Preview of Lubrication and Sensor Test Data

For the B3 engine at normal operating temperature, the oil-pressure inspection specifies 99–196 kPa at 1,000 rpm and 294–392 kPa at 3,000 rpm. These are test readings, distinct from the oil pump’s regulated-pressure specification.

The EGI-S water thermosensor table relates resistance to coolant temperature: 2.21–2.69 kΩ at 20°C and 0.29–0.354 kΩ at 80°C. The accompanying graph illustrates how resistance changes as the sensor warms.