Vehicle Class:
Compact Executive Sedan/Wagon
Target Audience:
Enthusiasts, DIY mechanics, independent repair shops specializing in European vehicles.
Competitors Late 80S:
BMW 3 Series (E30), Mercedes-Benz 190E (W201), Volvo 240, Acura Integra, Toyota Camry.
Design Philosophy:
Sporty handling, refined interior, Quattro all-wheel drive option, sophisticated engineering for its era.
Value Proposition:
Provides detailed, factory-accurate information essential for maintaining and repairing the Audi 90, saving significant costs compared to dealership service.
Engine Mechanical:
Complete engine overhaul, component diagnostics, timing belt replacement, piston and ring installation, cylinder head repair, valve train service, lubrication system, cooling system.
Engine Electrical:
Ignition system, fuel injection system (CIS-E/Motronic), starting system, charging system, engine control unit (ECU) diagnostics, sensor and actuator testing, wiring diagrams.
Transmission Manual:
Clutch system, gearbox overhaul, shift linkage adjustment, differential service, fluid specifications and replacement.
Transmission Automatic:
Transmission overhaul, torque converter service, hydraulic control systems, electronic control unit (TCU) diagnostics, fluid replacement and adjustment.
Suspension And Steering:
Front and rear suspension component replacement, shock absorber and strut service, ball joint and tie rod end replacement, power steering system service, wheel alignment specifications.
Brakes:
Front and rear brake system (disc brakes), ABS (Anti-lock Braking System) diagnostics and repair, brake fluid replacement, caliper and rotor service, parking brake adjustment.
Electrical System:
Lighting systems (headlights, taillights, interior), power windows, central locking, horn, wiper system, fuse and relay identification and testing, wiring diagrams for all vehicle systems.
Body And Chassis:
Body panel repair and replacement, door mechanisms, hood and trunk operation, bumper systems, interior trim removal and installation, rust prevention and repair.
HVAC:
Heating, ventilation, and air conditioning (HVAC) system diagnostics, refrigerant handling, component replacement (compressor, condenser, evaporator), blower motor service.
Maintenance:
Routine maintenance schedules, oil and filter changes, spark plug replacement, air filter replacement, coolant flushes, brake fluid changes, fuel filter replacement.
Troubleshooting:
Diagnostic flowcharts for common drivability issues, electrical system faults, starting problems, and performance issues.
Repair:
Step-by-step repair instructions for all major vehicle systems, including component removal, installation, and adjustment.
Diagnostics:
Detailed diagnostic procedures using specifications, test procedures for sensors, actuators, and control modules.
Depth Level:
Comprehensive (from basic maintenance to full engine/transmission rebuilds and complex electrical diagnostics).
Engine Code Common:
NG (2.3L 5-cylinder)
Engine Type:
Inline 5-cylinder, naturally aspirated
Displacement:
2309 cc (2.3 Liters)
Horsepower Peak:
130 hp @ 5500 rpm (for NG engine)
Torque Peak:
145 lb-ft @ 3000 rpm (for NG engine)
Fuel Delivery:
Bosch CIS-E (Continuous Injection System - Electronic) or Motronic electronic fuel injection, depending on model year and market.
Fuel Type:
Unleaded Gasoline
Coolant Type:
Ethylene Glycol based coolant (e.g., G11 specification).
Oil Type:
API SG/SH, SAE 5W-30 or 5W-40 (check manual for specific recommendations).
Transmission Type Standard:
5-speed Manual Transmission
Transmission Type Optional:
ZF 4-speed Automatic Transmission
Drivetrain:
Front-Wheel Drive (FWD) or Quattro All-Wheel Drive (AWD)
Manual Transmission Fluid:
API GL-4, SAE 75W-90 synthetic gear oil.
Automatic Transmission Fluid:
ATF Dexron II or equivalent.
Wheelbase:
Approx. 2600 mm (102.4 in)
Length:
Approx. 4400 mm (173.2 in)
Width:
Approx. 1700 mm (66.9 in)
Height:
Approx. 1380 mm (54.3 in)
Curb Weight FWD:
Approx. 1250 kg (2756 lbs)
Curb Weight Quattro:
Approx. 1350 kg (2976 lbs)
Gross Vehicle Weight Rating:
Varies by configuration, refer to vehicle data plate.
NHTSA Ratings:
Data for this era is less standardized. Generally considered safe for its time. (Specific ratings may not be readily available).
ABS:
Available (standard on many Quattro models, optional on FWD).
Airbags:
Driver airbag standard from 1990/1991 onwards. Passenger airbag optional or unavailable.
Seatbelts:
3-point inertia-reel seatbelts front and rear.
Quattro AWD Benefit:
Enhanced traction and stability, particularly in adverse weather conditions.
Audio System:
Factory AM/FM cassette stereo with optional CD player. Premium sound systems available.
Dashboard Features:
Analog gauges, driver information display (basic functions like outside temp, fuel economy).
ABS System:
Bosch Anti-lock Braking System (ABS) on select models.
Early Electronics:
Central locking, power windows, power mirrors, cruise control (optional).
Oil Change Interval:
Every 5,000-7,500 miles or 6-12 months, whichever comes first (synthetic oil recommended).
Timing Belt Replacement:
Every 60,000 miles or 5 years (critical component, failure can cause catastrophic engine damage).
Spark Plug Replacement:
Every 30,000 miles (standard plugs) or 60,000 miles (platinum plugs).
Coolant Flush Interval:
Every 2 years or 30,000 miles.
Power Steering Fluid:
Pentosin CHF 11S or equivalent hydraulic fluid.
Brake Fluid Type:
DOT 3 or DOT 4.
Common Problems:
Worn suspension bushings, aging electrical connectors and wiring harnesses, fuel distributor leaks (CIS-E), weak fuel pumps, cracked dashboard material, seized sunroof mechanisms, door seal degradation.
Engine Mounts:
Hydraulic engine mounts can degrade over time, leading to vibration.
Odometer Gears:
Plastic odometer gears in the instrument cluster are prone to breaking.
