🏷️ Basic Information

Make:

BMW

Model:

8-Series

Chassis Code:

E31

Year:

1991

Generation Code:

First Generation (E31)

Product Name:

BMW 8-series E31 1991 Service and Repair Manual

👋 Introduction

Positioning:

The BMW E31 8-Series was BMW's flagship luxury coupe, positioned as a premium grand tourer, competing with models like the Mercedes-Benz SL and Jaguar XJS. It emphasized advanced technology, performance, and refined luxury for its era.

Competitors:

Primarily competed against European luxury coupes and grand tourers of the late 1980s and 1990s, offering a blend of performance, comfort, and cutting-edge design.

Manual Advantages:

Vehicle-specific, factory-quality repair information, complete A-Z coverage, step-by-step instructions, diagrams, illustrations, wiring schematics, ease of use (single PDF), printable pages, digital format benefits (no wear and tear).

📋 Manual Details

Market Segment:

Luxury Grand Tourer

All Models Trims:

States 'COVERS ALL MODELS & ALL REPAIRS A-Z' for the 1991 E31, implying comprehensive coverage regardless of specific engine or trim variants available that year.

Estimated Page Count:

Extensive (Specific count not provided, but described as 'complete')

Type:

Factory Service Manual / Repair Manual

Language:

English

Format:

PDF

Searchability:

As a PDF, it is likely searchable, allowing users to quickly find specific terms or components.

Digital Benefits:

Easy to use, searchable, printable, zoomable images, organized into a single file, no physical wear and tear.

📖 Manual Coverage

Engine:

Complete service, diagnosis, and repair for all engine variants applicable to the 1991 E31. Includes specific details on fuel delivery, ignition, emissions, cooling, lubrication, and control systems.

Transmission:

Covers both automatic and manual transmissions, including operation, diagnosis, repair, and fluid specifications. Includes propeller shaft and drivetrain components.

Brakes:

Comprehensive coverage of the hydraulic brake system, including ABS, parking brake, brake control modules, and component repair/replacement. Includes service specifications.

Suspension Steering:

Detailed information on front and rear suspension, axle systems, wheels, tires, power steering, and steering column components. Includes alignment specifications.

Electrical Electronics:

Extensive coverage of the vehicle's electrical system, including wiring schematics, component testing, diagnosis of common electrical faults, battery, charging system, starter, lighting, instruments, and multiplex/CAN communication.

Body Interior:

Coverage of exterior and interior components, including doors, door locks, windows, mirrors, glass, hood, seats, instrument panel, and HVAC (air conditioning) systems.

Safety Systems:

Detailed information on Supplemental Restraint System (SRS) and seat belt mechanisms. Includes engine immobilizer and cruise control systems.

Instrumentation Gauges:

Diagnosis and repair of instrument cluster, warning lights, gauges, and on-board computer functions.

HVAC:

Air conditioning system service, diagnosis, refrigerant handling, blower motor, climate control unit repair.

Lighting:

Headlights (including pop-up mechanism), taillights, interior lighting, diagnostic procedures for electrical faults.

Interior Trim:

Removal and installation of interior panels, seats, door cards, dashboard components.

Exterior Trim:

Body panel removal and installation, bumper components, moldings, exterior trim pieces.

Maintenance:

Complete routine maintenance procedures, service intervals, fluid recommendations, and checks.

Diagnosis Troubleshooting:

Step-by-step diagnostic procedures for identifying and resolving faults across all vehicle systems, supported by diagrams and specifications.

Repair Rebuild:

Detailed instructions for component repair and rebuilding, from minor adjustments to major overhauls, accompanied by torque specifications and clearances.

Installation Replacement:

Guidance on the correct installation and replacement of parts and components.

Wiring Schematics:

Detailed, system-specific wiring diagrams are a key component, enabling accurate diagnosis of electrical issues.

Troubleshooting Charts:

Integrated troubleshooting flowcharts and symptom-based diagnostic guides for common problems.

Depth:

Factory-level, in-depth technical information suitable for professional technicians and knowledgeable DIY enthusiasts. Covers 'everything you will ever need'.

Diagnostic Tools:

While the manual itself is the primary tool, it implicitly guides users on how to utilize diagnostic procedures that may involve multimeters, oscilloscopes, and potentially early BMW diagnostic equipment or general OBD-II principles if applicable to the 1991 model.

📊 Manual Specifications

Format:

PDF

Printability:

Fully printable; users can print specific pages or diagrams as needed. Images can be blown up for enlarged copies.

Binding:

Digital (PDF); eliminates the need for physical binding, grease, or torn pages.

Paper Type:

N/A (Digital format)

Operating Systems:

Windows (Vista 32/64, XP, ME, 98, NT, 2000) and Mac compatible.

Software Requirements:

Adobe PDF Reader and Winzip (free online).

⚙️ Engine Specifications

Engine Options 1991:

The 1991 model year E31 was primarily offered with the M60 V8 engine. Specific variants for the US market typically included the 850i (5.0L V12 - though V12s debuted slightly later in certain markets, 1991 model year often associated with initial V12 introduction for 850i, while V8 models like 840i came later). The manual description implies coverage of all engines for the 1991 E31, so likely includes early V12 models if applicable to the specified year. Further clarification would rely on specific market introductions for the 1991 model year. Assuming the manual covers the initially released models for that year.

Typical Performance V12:

The 5.0L M70 V12 engine (in the 850i) produced approximately 300-310 hp and 330-347 lb-ft of torque, offering smooth, powerful acceleration.

System Type:

Bosch Motronic electronic fuel injection (EFI) systems were standard for both V8 and V12 engines.

Common Tasks:

Spark plug replacement, ignition coil diagnosis, fuel injector servicing, oil and filter changes, cooling system maintenance.

Engine Management:

BMW Motronic DME (Digital Engine Electronics) systems for precise control of fuel injection and ignition timing.

🔧 Transmission

Transmission Type Standard:

For the 1991 E31, the 850i was typically equipped with a 4-speed automatic transmission (e.g., GM 4L30-E derivative or ZF unit). A 6-speed manual transmission ( Getrag S6-40D) was also available on some early models or specific markets.

Transmission Type Optional:

6-speed manual transmission (Getrag S6-40D) was an option for V12 models.

Transmission Features:

The manual covers clutch service (for manual), automatic transmission internal repair, torque converter service, and transmission control module diagnosis.

Driveshaft Components:

Manual covers propeller shaft, universal joints, and center support bearings.

Differential Service:

Service and specifications for the rear differential unit, including fluid types and capacities.

📐 Dimensions

Wheelbase:

Approx. 2,578 mm (101.5 in)

Length:

Approx. 4,780 mm (188.2 in)

Width:

Approx. 1,855 mm (73.0 in)

Height:

Approx. 1,370 mm (53.9 in)

Curb Weight:

Approx. 1,700 - 1,800 kg (3,750 - 3,970 lbs) depending on engine and options.

Wheel Bolt Pattern:

Typically 5x120 mm.

Typical Tire Sizes:

Commonly 235/45R17 or 245/40R17 for front and rear, depending on wheel size and vehicle specification.

🛡️ Safety Features

Safety Features General:

The E31 was equipped with advanced safety features for its time, including anti-lock braking system (ABS), and a robust chassis structure.

Active Safety:

Anti-lock Braking System (ABS), Traction Control System (ASC/ASC+T on later models, likely not standard on 1991).

Passive Safety:

Supplemental Restraint System (SRS) airbags for driver and front passenger, advanced seat belt systems, crumple zones.

💡 Technology Features

Infotainment Features Early:

The 1991 E31 featured an early integrated infotainment system including a radio, cassette player, and a multi-function display (MFD) providing vehicle status information. Navigation systems were generally not standard or widely available on this specific early model year.

Driver Assistance Features:

ABS was standard. Features like cruise control were available. Advanced driver assistance systems (ADAS) as known today were not present.

Connectivity Features:

Limited connectivity by modern standards. Primarily internal vehicle diagnostics and status reporting via the MFD. No external connectivity like Bluetooth or Wi-Fi.

🔧 Maintenance

Oil Change Interval:

Typically every 10,000-15,000 miles or annually, depending on driving conditions and BMW's Condition Based Service (CBS) system if applicable to early models, or based on mileage recommendations in the manual.

Spark Plug Replacement:

Can range from 30,000 to 60,000 miles depending on the specific plug type and engine. The manual will provide precise intervals and specifications.

Engine Oil Type:

Typically a synthetic or synthetic blend oil meeting BMW LL-XX specifications. For 1991 models, likely a high-quality 5W-30 or 10W-40. Manual will specify exact BMW approval.

Coolant Type:

BMW's specific ethylene glycol-based coolant (often blue or green for this era) or equivalent. Capacity around 10-12 liters.

Brake Fluid Type:

DOT 4 or DOT 4 Plus brake fluid meeting BMW specifications.

Common E31 Issues:

E31s are known for potential issues with the aging of the wiring harness (especially insulation degradation), ABS/ASC sensors and modules, fuel pump relay failures, catalytic converter issues, and cooling system components (e.g., plastic expansion tank). The manual would provide diagnostic procedures for these and more.

📚 Vehicle History

Bmw Heritage:

BMW's history is rooted in aircraft engine manufacturing, transitioning to motorcycles and then automobiles. The brand is renowned for its 'Ultimate Driving Machine' ethos, emphasizing performance, engineering, and driver engagement.

E31 Evolution:

The E31 8-Series was a departure for BMW, designed as a flagship grand tourer, featuring a more sophisticated and luxurious approach than previous coupes. It introduced a V12 engine to BMW's passenger car lineup and featured pop-up headlights, a design element characteristic of many sports cars of the era.

Production Years:

1989-1999

Manufacturing Locations:

Dingolfing, Germany

🏆 Awards & Recognition

Model Recognition:

While specific awards for the 1991 model year might be scarce, the BMW 8-Series (E31) was generally praised for its groundbreaking design, performance, and technological innovation at the time of its release. It is considered a modern classic and an icon of 1990s automotive design.