🏷️ Basic Information Identification Make: Audi Model: 90 Quattro Year: 1991 Codes Chassis Code: Type 8B 👋 Introduction Market Position Positioning: Premium compact sedan and coupe segment, known for its sophisticated quattro all-wheel-drive system and driver-focused engineering. Competitive Analysis Competitors: BMW 3 Series (E30/E36), Mercedes-Benz 190E, Acura Integra, Lexus ES250. Competed on performance, handling, and AWD capability. Key Features Vehicle Highlights: Permanent all-wheel-drive (Quattro), refined inline-five engine, excellent handling dynamics, build quality characteristic of Audi. Manual Value Proposition Value: Provides access to factory-derived, officially licensed repair information, offering a significant cost saving over dealership service. Enables DIY repairs for complex systems like the Quattro drivetrain and engine management. 📋 Manual Details Coverage Areas Primary Coverage: North America (US/Canada) Page Count Estimated Pages: Extensive (typical for OE-derived software, likely 1000+ pages equivalent) Manual Type Type: Official Service and Repair Manual Software Language Language: English Format Format: Online Software/Web-based Access 📖 Manual Coverage Systems Covered Engine: Complete overhaul, diagnosis, repair, tuning, fuel system, ignition system, cooling system, exhaust system Drivetrain: Quattro all-wheel drive system, differentials, driveshafts, CV joints, clutch, manual transmission, automatic transmission (if applicable) Brakes: Disc brakes (front and rear), ABS system diagnosis and repair, hydraulic system, parking brake Suspension And Steering: Front and rear suspension components, struts, shocks, control arms, bushings, power steering system, steering rack, alignment specifications Electrical System: Wiring diagrams, component location, starter, alternator, battery, lighting, fuses, relays, ECUs, diagnostic connectors Body And Chassis: Body panel removal/installation, interior trim, glass, doors, hinges, locks, structural repairs (limited, typically focuses on mechanical/electrical) Heating And Air Conditioning: HVAC system components, refrigerant circuits, blower motor, controls, climate control diagnosis Procedures Included Maintenance: Scheduled maintenance tasks, oil changes, filter replacements, fluid checks and changes, spark plug replacement, belt tensioning Troubleshooting: Diagnostic procedures for common and uncommon faults, fault code interpretation (if applicable), step-by-step diagnostic flowcharts Repair: Detailed instructions for component removal, overhaul, and installation for all covered systems Technical Specifications: Torque specifications, clearances, tolerances, pressures, electrical values Technical Depth Depth: Comprehensive, OE-level detail suitable for professional technicians and advanced DIY enthusiasts. Covers everything from basic maintenance to complete engine and transmission rebuilds. 📊 Manual Specifications File Format Digital Format: Web-based access via browser. Compatible with PC, laptop, smartphone, tablet. Requires internet connection. Print Quality Digital Quality: High-resolution, clear diagrams, schematics, and text. Searchable functionality. Binding Type Digital Binding: N/A (digital access) Paper Type Digital Paper Type: N/A (digital access) ⚙️ Engine Specifications Primary Engine Engine Code: NG (2.3E) Configuration: Inline-5 Cylinder, DOHC Displacement: 2.3 Liters (2309 cc) Performance Horsepower: 130 hp @ 5800 rpm (approx.) Torque: 137 lb-ft @ 3500 rpm (approx.) Fuel System Injection: Bosch KE-Jetronic (CIS-E) or similar Bosch electronic fuel injection system Ignition System System Type: Electronic ignition, distributorless ignition system (DIS) often featured on later versions, or distributor with electronic control. 🔧 Transmission Standard Type: 5-speed Manual Optional Type: 4-speed Automatic (e.g., ZF 4HP-22) Features Drivetrain: Torsen center differential (standard on Quattro models), viscous coupling rear differential (depending on specific variant/year) 📐 Dimensions Exterior Body Styles: 4-door Sedan, 2-door Coupe Weights Curb Weight: Approx. 3100-3400 lbs (1400-1540 kg) depending on body style and options. 🛡️ Safety Features Ratings Passive Safety: Occupant protection features typical for the era, including crumple zones, safety belts. Specific NHTSA/IIHS ratings for this year are less comprehensive than modern standards. Active Features Braking System: Standard Anti-lock Braking System (ABS) on Quattro models, typically front ventilated discs and rear solid discs. Passive Features Restraints: 3-point seat belts for all occupants, driver's side airbag often optional or standard depending on market and trim level. 💡 Technology Features Infotainment Audio System: Factory premium sound system, often with cassette player and AM/FM radio. Pre-wiring for CD changer may be present. Analog climate controls. Driver Assistance ABS: Standard ABS on Quattro models, a significant safety technology for its time. Connectivity Diagnostic Port: OBD I diagnostic connector (location varies, often under dash or in engine bay) for engine management and ABS diagnostics. Requires specific Audi diagnostic tools of the era or adaptable scanners. 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 5,000-7,500 miles (8,000-12,000 km) or 6-12 months, depending on driving conditions and oil quality used. Refer to manual for precise OE recommendations. Timing Belt Interval: Crucial: Usually around 60,000 miles (96,000 km) or 4-5 years for the 5-cylinder engine. Failure can cause severe engine damage. Fluid Specifications Engine Oil: SAE 5W-40 or 10W-40 synthetic or semi-synthetic oil meeting VW 502 00 or API SG/SH specifications (consult manual for precise spec). Coolant: Ethylene glycol-based antifreeze, typically G11 specification (blue/green color) or equivalent, mixed 50/50 with distilled water. Transmission Fluid Manual: API GL-4 or GL-5 gear oil, SAE 75W-90 or 80W-90. Check differential fluid separately. Transmission Fluid Automatic: Dexron III or equivalent ATF. Capacity typically around 4-5 liters. Brake Fluid: DOT 3 or DOT 4 brake fluid. Known Issues Common Faults:...