🏷️ Basic Information

Make:

BMW

Model:

8 Series

Chassis Code:

E31

Model Year:

1991

Specific Model Variant:

850i

👋 Introduction

Market Segment:

Luxury Grand Tourer (GT) / Sports Coupe

Key Competitors Era:

Porsche 928, Mercedes-Benz SL-Class (R129), Jaguar XJS

Defining Characteristics:

Sophisticated V12 engine, advanced electronics, striking design, high-quality interior, emphasis on long-distance comfort and performance.

Benefit To Owner:

Empowers owners to perform maintenance and repairs efficiently, reducing reliance on expensive dealership services and preserving vehicle value.

📋 Manual Details

Coverage Years:

1991

Manual Type:

Factory Repair Manual / Service Manual

Language:

English

File Format:

PDF (distributed via WINRAR)

Delivery Method:

Instant Download

Estimated Page Count:

Likely exceeds 1000 pages (typical for comprehensive factory repair manuals of this era)

📖 Manual Coverage

Systems Covered:

Maintenance and General Instructions, Motor (Engine), Engine Electrics, Fuel Preparation and Control, Fuel Tank and Lines, Radiator, Exhaust System, Clutch, Gearbox, Drive Chain (Driveshaft/Differential), Steering, Rear Wheel Drive System, Brakes, Wheels and Tires, Frame/Chassis, Equipment, General Electrical Equipment, Instruments, Lights

Procedures Included:

Troubleshooting, diagnostic procedures, repair procedures, maintenance schedules, component replacement, system adjustments, wiring diagrams, technical data specifications

Technical Depth:

Comprehensive factory-level repair and maintenance information, suitable for professional technicians and advanced DIY enthusiasts.

Wiring Diagrams Detail:

Includes detailed wiring diagrams for all major electrical systems, crucial for diagnosing complex electronic faults.

📊 Manual Specifications

Digital Format Details:

Searchable PDF content within a WINRAR archive for efficient download and extraction. Compatibility with Windows, Linux, and MAC operating systems.

Print Quality Replication:

Designed to replicate original factory manual quality, providing clear text and legible diagrams. Enables high-quality printing.

Binding Type Digital:

N/A (Digital File)

Paper Type Digital:

N/A (Digital File)

Manual Completeness Level:

Full factory service manual, covering all aspects of repair and maintenance for the specified model year and chassis code.

⚙️ Engine Specifications

Engine Code Variant:

M70B50

Displacement Liters:

5.0

Configuration:

V12

Horsepower Hp:

300 (approx. @ 5200 RPM)

Torque Lb Ft:

330 (approx. @ 4100 RPM)

Fuel Delivery:

Bosch Motronic M5.2 Fuel Injection

Cooling System Type:

Liquid-Cooled

Radiator Fan Control:

Electrically controlled radiator fan with variable speed, managed by the engine control unit.

Ignition System:

Distributorless Electronic Ignition (DIS) with dual ignition coils per cylinder bank

Bore X Stroke:

84.0 mm x 75.0 mm

Emission Controls:

Catalytic converters, secondary air injection (may vary by market)

🔧 Transmission

Transmission Type Std:

4-Speed Automatic

Automatic Transmission Model:

ZF 4HP24

Transmission Type Opt:

6-Speed Manual (Rare option, primarily on 850CSi later, but potential for early variants)

Traction Control:

ASC+T (Automatic Stability Control and Traction)

Automatic Transmission Fluid Type:

BMW ATF LT-3 or equivalent Dexron III/Mercon

Manual Transmission Fluid Type:

BMW MTF LT-1 or equivalent GL-4 gear oil

📐 Dimensions

Length Mm:

4785

Width Mm:

1855

Height Mm:

1370

Wheelbase Mm:

2632

Front Track Mm:

1550

Rear Track Mm:

1545

Curb Weight Kg:

1850 (approx. for 850i auto)

Gross Vehicle Weight Rating Kg:

2300 (approx.)

Fuel Tank Capacity Liters:

80

🛡️ Safety Features

Crash Test Ratings:

N/A (Era of limited official crash test data for this segment)

Braking System:

Anti-lock Braking System (ABS) standard on all wheels

Stability Control:

ASC+T (Automatic Stability Control and Traction)

Airbags:

Driver's airbag standard

Seatbelts:

Three-point inertia-reel seatbelts front and rear

Body Construction:

Monocoque with integrated safety cell, designed for torsional rigidity and occupant protection.

💡 Technology Features

Audio System:

BMW Bavaria C Business/Professional radio cassette system with CD changer preparation.

Climate Control:

Dual-zone automatic climate control

Cruise Control:

Standard electronic cruise control

Suspension:

Optional Electronic Damper Control (EDC) system allowing driver selection of suspension stiffness.

Remote Locking:

Central locking with remote control (key fob) and vacuum-assisted system for doors, trunk, and fuel filler flap.

Headlights:

Projector-type headlights with integrated fog lights. Manual headlight leveling.

Window Control:

Electrically operated windows and side mirrors.

🔧 Maintenance

Oil Change Interval Km:

10,000 - 15,000 km or 12 months (depending on oil type and driving conditions, consult manual for specific recommendations)

Spark Plug Replacement Interval:

Approximately 50,000 - 100,000 km, depending on spark plug type (e.g., copper, platinum, iridium)

Engine Oil Type:

BMW High Performance Synthetic SAE 0W-40 or 5W-40 (API SH/SJ or higher, ACEA A3/B3)

Engine Oil Capacity Liters:

7.5 (with filter)

Coolant Type:

BMW Blue Antifreeze/Coolant (Glysantin G48 or equivalent ethylene glycol-based coolant with corrosion inhibitors)

Brake Fluid Type:

DOT 4

Common Problems Early E31:

Component failures in the electronic damping control (EDC), ABS/ASC control modules, aging wiring harnesses, fuel injector issues, starter motor failure, and potential cooling system leaks due to aged components.

Door Seal Issues:

Vacuum-operated door locks and seals can be a source of leaks or operational failures; maintenance of the vacuum system is crucial.

Major Service Points:

Regular inspection and replacement of V-belts, fuel filters, air filters, coolant hoses, brake pads/rotors, and attention to the complex electrical system are critical.

📚 Vehicle History

Bmw Philosophy Era:

Focus on 'The Ultimate Driving Machine', blending luxury, performance, and advanced engineering.

E31 Introduction:

Introduced in 1989 (as a 1990 model in some markets) as a successor to the BMW 6 Series (E24) and a more performance-oriented alternative to the 7 Series (E32).

E31 Development Goals:

To create a flagship coupe that was aerodynamically advanced, technologically innovative, and offered exceptional performance and luxury.

Manufacturing Plant:

Dingolfing Plant, Germany

Production Years E31:

1989-1999

🏆 Awards & Recognition

Design Awards:

Often praised for its distinctive 'Bangle-less' design language, aerodynamic efficiency, and long-distance comfort, contributing to its status as a modern classic.

Performance Reviews:

Consistently rated highly by automotive journalists for its V12 engine smoothness, handling balance, and luxurious interior.