Porsche 911 Carrera 930/21 & 930/25 Carrera Coupe, Targa, Cabriolet 1984–1989 Service Manual (ISBN 0-8376-0291-2)

• Covers 1984–1989 Porsche 911 Carrera Coupe, Targa, and Cabriolet models with the 3.2-liter air-cooled flat-six in 930/21 (1984–1986) and 930/25 (1987–1989) form.
• Separates the two driveline builds: the 915 five-speed with cable-operated clutch for 1984–1986 and the G50 five-speed with hydraulic clutch for 1987–1989.
• Takes engine repair from complete engine/transmission removal through teardown and reassembly, crankcase and crankshaft inspection, piston/cylinder matching, cylinder-head reconditioning, camshaft service, timing-chain work, and dry-sump lubrication diagnosis.
• Details Bosch DME/Motronic driveability troubleshooting, fuel-pressure and delivery testing, ECM connector checks, injector and sensor testing, ignition diagnosis, and exhaust/emissions component repair.
• Documents clutch and shifter service, 915 internal transmission work, front and rear suspension, steering, wheel bearings, CV joints, hydraulic and mechanical brakes, ride-height setup, and wheel alignment.
• Includes body and climate procedures for the Targa top, doors, windows, sunroof, bumpers, seats and trim, automatic heating, ventilation controls, and A/C component diagnosis and replacement.
• Provides a 92-page Group 970 wiring section, electrical component-location tables, special-tool references, and torque, capacity, wear, alignment, pressure-test, and electrical test data; 717-page PDF, Bentley code P989.

Model Identification and Maintenance

Published by Bentley Publishers, this is an independent service manual—not a Porsche-issued factory workshop publication. The ten numbered sections run from maintenance and engine work through the drivetrain, chassis, body, climate-control, and electrical systems.

Identification pages show where to find the VIN, date-of-manufacture label, engine number, transmission code, and paint code. That is useful on cars built near a model-year change, where installed components may follow the earlier production configuration.

The maintenance group supplies oil-service, mileage-based, and time-based schedules, along with procedures and checks for valve clearance, filters, spark plugs, V-belts, oxygen sensor, wheel bearings, brakes, clutch, suspension, fuel lines, wipers, and body lubrication. Fluid and lubricant tables cover viscosity ranges, approved specifications, and system capacities.

Engine, DME, and Drivetrain Procedures

The engine chapters document removal of the engine and transmission as one assembly, separation and rejoining, full disassembly and reassembly, and the handoff to individual reconditioning groups. Those groups cover crankcase and intermediate-shaft inspection, crankshaft gears and bearings, piston/cylinder identification and wear checks, valve guides and seats, valve-spring setup, camshaft and rocker-shaft work, oil-spray-tube service, chain tensioners, and final camshaft timing adjustment.

Bosch DME coverage is organized around fault isolation. It includes fuel pressure, delivery-volume, and residual-pressure tests; injector checks; ECM connector pin assignments; volume-air-flow, temperature, reference/speed, throttle-position, and idle-control testing; oxygen-sensor diagnosis; and evaporative-emissions checks. Ignition and exhaust sections add distributor, rotor, plug-wire and crankshaft-sensor service, catalytic-converter checks, and replacement procedures for the muffler, heat exchangers, and catalytic converter.

The 915 chapters cover the shifter, controls and case, input and output shafts, synchronizers, dog teeth, seals, and reassembly. Clutch coverage distinguishes the cable-operated system from the later hydraulic setup, with pedal-cluster work, release-system adjustment, hydraulic bleeding, and master/slave-cylinder replacement. Internal G50 gear-and-shaft overhaul is not covered, and differential repair is limited to diagnosis and axle-flange seals rather than differential disassembly.

Chassis and Body Repair, Climate and Electrical Diagnosis

Chassis repair includes struts and cartridges, ball joints, control arms, torsion bars, ride-height setting, wheel bearings, axle shafts and CV joints, steering rack and column work, brake bleeding, master cylinder and booster service, calipers, pads, rotors, parking brake, and front/rear alignment.

Body sections cover Targa-top removal, folding and latch adjustment; door and window-frame service; Coupe versus Targa/Cabriolet window adjustment; sunroof emergency closing, panel adjustment, cables, motor and guide rails; bumpers, seats, mirrors, dashboard, and console trim. Heating and A/C material for the original R-12 system includes automatic-heating troubleshooting, sensors, blowers, control cables, A/C pressure and electrical testing, compressor/clutch, receiver-dryer, condensers, expansion valve, and evaporator housing. Refrigerant discharge, evacuation, and recharge methods are outside the A/C repair scope.

The wiring material is divided into 1984, 1985, 1986–1987, and 1988–1989 production groups. Representative schematics include Power Distribution, Ground Distribution, DME Engine Management, Convertible Top, Air Conditioning and Heating, and Instrument Panel circuits. Separate tables identify fuses, relays, control modules, grounds, and year-specific fuse assignments.

Special-tool callouts include the P 238 A flywheel locking tool, P 9191 camshaft-sprocket counterholding wrench, P 212 camshaft-sprocket lockpin tool, P 370 clutch-disc alignment tool, and P 355a input-shaft mounting tool. The piston-and-cylinder section distinguishes Mahle/Nikasil from KS/Alusil combinations and warns against interchanging used parts between cylinders. DME testing cautions that improper meter probes can spread small connector terminals and create new intermittent faults.

Engine/transmission removal, brake hydraulic work, and any refrigerant handling require suitable lifting equipment, electrical isolation, proper shop procedures, and experienced judgment.