Vehicle Segment:
Luxury Grand Tourer (GT)
Brand Perception:
High-performance, engineering excellence, luxury
Competitors Era:
Ferrari 400i/412, Aston Martin V8 Vantage, Jaguar XJS
Unique Selling Proposition:
Front-engine V8, rear transaxle, advanced engineering for its time, comfortable yet sporty GT
Target Audience:
Porsche 928 owners, independent mechanics, automotive enthusiasts with electrical diagnostic skills
Cost Saving Potential:
Enables DIY troubleshooting and repair, reducing reliance on expensive dealership or specialist labor for electrical issues
Powertrain Electrical:
Engine Control Unit (ECU), Fuel Injection, Ignition System, Starter, Alternator
Chassis Electrical:
Braking System (ABS), Power Steering, Suspension Control (if applicable)
Body Electrical:
Lighting (Headlights, Taillights, Interior), Wipers, Horn, Central Locking, Power Windows, Power Seats, Mirrors
Comfort Convenience:
Climate Control (HVAC), Cruise Control, Audio System, Instrumentation Cluster, Warning Lights
Safety Security:
Airbag System (if equipped), Alarm System
Troubleshooting:
Step-by-step diagnostic flows, symptom-based problem solving
Repair Tasks:
Component replacement, wire repair, connector servicing
Installation:
Wiring harness installation/replacement (general guidance)
Depth:
Detailed component locations, connector pinouts, wire colors, fuse/relay assignments, circuit diagrams
Engine Type:
V8, Naturally Aspirated
Displacement:
4.7 Liters (for early 928 S)
Displacement 1989 Model:
5.0 Liters (for 928 S4, which likely applies to '89 model year)
Bore X Stroke 5.0L:
97.0 mm x 84.0 mm
Compression Ratio 5.0L:
10.0:1
Horsepower 5.0L:
316 hp (235 kW) at 6000 rpm (Euro Spec), 306 hp (225 kW) for US Spec
Torque 5.0L:
315 lb-ft (427 Nm) at 4800 rpm (Euro Spec), 320 lb-ft (434 Nm) for US Spec
Fuel Delivery:
Bosch L-Jetronic Fuel Injection (later Motronic)
Fuel Type:
Unleaded Premium Gasoline
Cooling Type:
Liquid-cooled
ECU Type Common:
Bosch Motronic
Transmission Type Standard:
5-Speed Manual transaxle (G50 gearbox became more prevalent for later models)
Transmission Type Optional:
3-Speed Automatic (automatic with manual override later)
Drive Layout:
Rear-wheel drive (RWD) with rear transaxle
Transaxle Design:
Integrated clutch and gearbox for weight distribution and handling balance
Length:
Approx. 4,655 mm (183.3 in)
Width:
Approx. 1,775 mm (69.9 in)
Height:
Approx. 1,280 mm (50.4 in)
Wheelbase:
Approx. 2,447 mm (96.3 in)
Curb Weight Manual:
Approx. 1,560 kg (3,439 lbs)
Curb Weight Automatic:
Approx. 1,580 kg (3,483 lbs)
Gross Vehicle Weight Rating:
Approx. 2,030 kg (4,475 lbs)
Towing Capacity:
Not Recommended
NHTSA Ratings:
N/A (Testing standards and availability varied significantly in the 1980s)
IIHS Ratings:
N/A (IHHS was not established in its current form)
ABS:
Standard on 1989 models (Bosch ABS II)
Traction Control:
Optional (ASR - Automatic Slip Regulation) on some later models, but less common for the '89 S
Airbags:
Driver-side airbag standard for 1989 models
Seatbelts:
3-point front and rear seatbelts
Body Structure:
Reinforced chassis and crumple zones
Audio System:
Premium sound system, often Blaupunkt or Becker units with cassette player
Speakers:
Multiple speaker configurations, including door-mounted and rear shelf speakers
Cruise Control:
Standard feature
Instrumentation:
Comprehensive analog gauges including tachometer, speedometer, oil pressure, oil temperature, voltmeter, and fuel level
OBD Ii Port:
N/A (OBD-II standard was not in widespread use in 1989; diagnostic connectors are proprietary)
Climate Control:
Automatic climate control (HVAC) with electronic sensors
Power Features:
Power windows, power adjustable seats, power mirrors
Oil Change Interval:
Every 5,000-7,500 miles or 1 year, whichever comes first (consult specific owner's manual)
Timing Belt Interval:
Every 30,000 miles or 3 years (crucial for V8 engine)
Brake Fluid Flush:
Every 2 years
Engine Oil Type Viscosity:
SAE 5W-40 or 10W-40 synthetic (check owner's manual for exact specs and API rating)
Coolant Type:
Porsche approved antifreeze, typically a silicate-free G12 or similar specification
Transmission Fluid Manual:
GL-4 or GL-5 gear oil, SAE 75W-90
Transmission Fluid Automatic:
Dexron II or III (check specific model year)
Electrical Common Complaints:
Faulty door lock actuators, intermittent gauge cluster issues, HVAC blower motor failures, headlight switch problems, aging wiring insulation breakdown
Mechanical Common Complaints:
Timing belt failure (catastrophic), water pump leaks, coolant hoses deterioration, CV joint wear, pop-up headlight mechanism issues
Oil Filter Part Number Example:
Mann-Filter W 920/1, Mahle OC 27
Air Filter Part Number Example:
Mann-Filter C 33 410
Founding Era:
1931 (Ferdinand Porsche)
Significant Updates Leading To 89:
Introduction of 928 S (1978/79), S2 (1980), S3 (US Spec - 1984), S4 (1986) with significant engine power, suspension, and aerodynamic improvements.
1989 Specific Features:
Continued refinement of the S4 model, potentially minor electrical or comfort feature updates.
Production Years:
1977-1995
Manufacturing Location:
Stuttgart, Germany
Total Production Numbers:
Approx. 61,000 units across all variants
