1984–1991 Audi 90 (B2, B3) Service and Repair Manual PDF

Description

Audi 90 (B2 and B3) Service and Repair Manual — 1984 to 1991

The Audi 90 was the upmarket, more powerful sibling of the 80 — the same body given better engines, more equipment, and, crucially, Audi’s inline-five. It is the five-cylinder that defines the car and separates it from a well-specified 80, and on the B3 cars it culminated in Audi’s first mass-produced 20-valve engine, a genuine landmark.

These are honest, rugged, galvanised cars that survive well and reward correct maintenance. But they are also old, mechanically injected on many variants, and fitted with a mechanical safety system most modern technicians have never encountered. That is where proper documentation earns its place.

What the Audi 90 is

The 90 was built across two platforms:

• B2 (Typ 81/85, 1984–1987) — the original 90, based on the B2 80/Coupé, distinguished by its five-cylinder engines and higher equipment level.
• B3 (Typ 89/8A, 1987–1991) — the aerodynamic, fully galvanised second generation. Visually set apart from the 80 by its full-width tail light panel, quad headlights and different grille, and mechanically by its five-cylinder engines — including the 20-valve.

Both were offered with front-wheel drive or quattro. The quattro cars use a mechanical Torsen or lockable differential system depending on year — permanent, driver-influenced all-wheel drive with no Haldex, no pump and no filter. The documentation keeps the two generations separate throughout, because they share less than their family resemblance suggests.

Engines covered

Engine	Generation	Notes
2.0 inline-five	B2 / B3	The base five-cylinder
2.2 inline-five	B2	Higher-output five
2.3 inline-five 10v	B3	NG — the popular 133–136 PS five
2.3 inline-five 20v	B3	7A — Audi’s first mass-produced 20v, 160 PS
1.6 turbo diesel	B3	Four-cylinder TD

The inline-five is the car’s signature — the engine that gives it that unmistakable warble and its character. The 2.3 20-valve (7A) is the one enthusiasts seek: Audi’s first large-scale four-valve-per-cylinder engine, closely related in concept to the heads that would define the S-cars. It is more complex than the 10-valve and documented as such.

Fuel injection — mostly mechanical, and its own discipline

Many of these cars run Bosch K-Jetronic or KE-Jetronic mechanical fuel injection — a system that meters fuel by hydraulic pressure and airflow, with barely a sensor in sight. If you have only ever worked on modern electronic engines, this is a completely different world, and the usual instincts lead nowhere.

System pressure testing, the warm-up regulator, the fuel distributor, mixture adjustment and cold-start behaviour are all documented. On a car of this age, most running complaints trace back here, and getting the injection right transforms how the car drives.

Procon-ten — read before removing an engine

The B3 cars can be fitted with Procon-ten, Audi’s mechanical occupant-protection system: steel cables link the engine to the steering column and seatbelts, held under permanent tension, so that in a frontal impact the steering wheel is pulled away from the driver and the belts tightened — with no sensors or explosives.

It is clever, it works, and it is permanently under tension. The cable routing, the tensioning specification, and the correct release and re-securing procedure whenever the engine or gearbox is removed are all documented. Do not lift the engine on a Procon-ten car without reading this first.

Transmission and drivetrain

Four- and five-speed manual — clutch, release bearing, linkage and fluid, for both generations.

Three- and four-speed automatic — fluid procedure and adjustment where fitted.

quattro (where fitted) — the mechanical all-wheel-drive system with its differential locking, driveline and final drives. Purely mechanical — no electronics, no Haldex.

Electrical and diagnostics

Full wiring diagrams for both generations, connector views and pinouts, the central electrics and relays, the instrument cluster and its voltage stabiliser, and fault code tables where applicable.

These are pre-OBD-II cars. Diagnosis is done with a multimeter and the wiring diagrams — a modern scan tool will tell you nothing. The documentation is written for that approach.

Known Audi 90 issues you will be looking up

• K-Jetronic / KE-Jetronic running faults — poor cold starting, uneven idle, hesitation. Almost always control pressure, the warm-up regulator or mixture, and testable rather than guessable.
• Wrong generation, wrong parts — B2 and B3 are not interchangeable. The documentation makes the identification explicit.
• 2.3 20v (7A) complexity — the 20-valve head, its timing and its specific service needs versus the 10-valve.
• Timing belt — interference engines. Interval, tensioner and water pump.
• Instrument cluster and voltage stabiliser — erratic gauges traced to the stabiliser rather than the senders.
• Wiring insulation degradation — decades-old looms cracking and shorting.
• Distributor, cap, rotor and ignition — misfire and hard starting.
• Rust despite galvanising — the B3 is galvanised, but age tells; the inspection points that matter.
• Central locking and window mechanisms — the age-related failures.
• Heater matrix and blower — a significant job, worth diagnosing correctly first.
• Procon-ten cable adjustment — on the cars fitted with it.

What’s inside this manual set

• Engine — the inline-five (10v and 20v) and four-cylinder, removal, overhaul, timing, torque
• Fuel and ignition — K-Jetronic / KE-Jetronic mechanical injection
• Cooling and lubrication
• Transmission — manual, automatic and, where fitted, quattro
• Clutch and driveshafts
• Brakes and, where fitted, Procon-ten
• Suspension and steering, with alignment data
• Body — panel repair, body dimensions, rust inspection points, trim
• Heating, ventilation and air conditioning
• Electrical — full wiring diagrams for both generations, connector views
• Diagnostics and pre-OBD fault-finding
• Maintenance schedules and service procedures

Format and delivery

Supplied as a set of searchable PDF files covering both the B2 (Typ 81/85) and B3 (Typ 89/8A) Audi 90, clearly separated by generation. Readable and printable on any device: laptop, tablet, phone, or the workshop PC. No software to install, and no internet connection needed once the files are saved.

Select your year at checkout. After payment, your download link is sent within 24 hours.

Frequently asked questions

Which Audi 90 do I have?

A 1984–1987 car on the older body is the B2 (Typ 81/85). A 1987–1991 car with the aerodynamic look, full-width rear panel and quad headlights is the B3 (Typ 89/8A). The documentation is organised by generation, so once you know your type code you always know which section applies.

Does it cover the 20-valve engine?

Yes — the 2.3 20v (7A), Audi’s first mass-produced four-valve engine and the one enthusiasts prize. It is more complex than the 10-valve, with different timing and service needs, and it is documented separately.

Does it cover the mechanical fuel injection?

Yes, in detail — K-Jetronic and KE-Jetronic, including control pressure, the warm-up regulator, the fuel distributor and mixture setup. This is where most running faults on these cars are found.

What is Procon-ten and do I need to care?

If your B3 has it, yes — especially before removing the engine or gearbox. It is a mechanical safety system using steel cables under permanent tension. The release, tensioning and re-securing procedure is documented. Do not improvise with it.

My 90 is a quattro. Is that covered?

Yes. The mechanical all-wheel-drive system, its differential locking and driveline are covered. It is purely mechanical — there is no Haldex and no electronics deciding when it engages.

Can I use a modern OBD scanner?

No. These are pre-OBD-II cars, diagnosed with a multimeter and the wiring diagrams, and the documentation is built around that.

Are parts still available?

Many mechanical and service parts are, through specialists, but order for the correct generation — B2 and B3 share less than they appear to. The documentation makes the identification explicit.