The Audi JN is a 2,226 cc, inline-five petrol engine produced between 1985 and 1990. It features a naturally aspirated design with Bosch K-Jetronic continuous fuel injection and a single overhead camshaft (SOHC). In standard tune, it delivers 85 kW (115 PS) and 180 Nm of torque, serving as a mid-range powerplant in Audi's G-series platform.
Fitted to models such as the Audi 80 (B2) and Audi 100 (C3), the JN was engineered for smooth, linear power delivery and mechanical reliability in daily driving conditions. It features a cast-iron block with an aluminium head, hydraulic valve lifters, and a timing belt-driven valvetrain. Emissions compliance was achieved through air injection and catalytic converter technology, meeting early Euro 1 standards.
One documented concern is degradation of the fuel distributor in the K-Jetronic system, particularly in high-mileage or poorly maintained examples. This issue, referenced in Audi Service Information Bulletin 07-10-01, can lead to uneven fuel metering, rough idle, and reduced fuel economy. Audi recommends periodic inspection of control pressure and airflow metering flap operation to maintain optimal performance.
All JN engines meet early Euro 1 emissions standards (VCA UK Type Approval #VCA/EMS/2045), verified through UK Department for Transport homologation records.
The Audi JN is a 2,226 cc inline-five petrol engine developed for mid-size Audi platforms (1985–1990). It combines Bosch K-Jetronic mechanical fuel injection with a timing belt-driven SOHC valvetrain to deliver smooth, linear performance. Designed to meet early European emissions standards, it prioritizes mechanical durability and ease of service.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,226 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-5, SOHC, 10-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 81.0 mm × 86.4 mm | |
| Power output | 85 kW (115 PS) @ 5,200 rpm | |
| Torque | 180 Nm @ 3,500 rpm | |
| Fuel system | Bosch K-Jetronic continuous fuel injection | |
| Emissions standard | Euro 1 | |
| Compression ratio | 9.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Timing belt (renew every 60,000 km) | |
| Oil type | SAE 10W-40 (API SG) | |
| Dry weight | 168 kg |
The K-Jetronic fuel system provides predictable performance but requires periodic adjustment of control pressure and inspection of the airflow metering flap. Use of SAE 10W-40 API SG-compliant oil is essential for hydraulic lifter quietness and bearing protection. Extended service intervals increase risk of timing belt failure. The cast-iron block ensures durability but adds weight, affecting front/rear balance in FWD applications. Coolant system integrity is critical due to high operating temperatures; replace thermostat and hoses every 4 years. The timing belt must be replaced every 60,000 km per Audi SIB 07-10-01 to prevent valve/piston contact.
Oil Specs: Requires API SG specification (Audi SIB 07-10-01). Compatible with ACEA A2 standards.
Emissions: All JN engines meet Euro 1 standards (VCA Type Approval #VCA/EMS/2045), verified through DfT homologation.
Power Ratings: Measured under DIN 70020 standards. Output consistent across fuel qualities meeting EN 228.
Audi Technical Information System (TIS): Docs A22050, A22100, A22130, SIB 07-10-01
VCA Type Approval Database (VCA/EMS/2045)
DIN 70020 Engine Power Certification Standards
The Audi JN was used across Audi's B2/C3 platforms with longitudinal mounting and shared with Volkswagen Group commercial applications. This engine received platform-specific adaptations-integrated air injection in 80 and revised exhaust routing in 100-and from 1987 the facelifted C3 100 adopted updated catalytic converter calibration, creating emissions compatibility limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right side of the cylinder block near the transmission bellhousing (Audi TIS A22070). The 7th VIN digit indicates engine family ('J' for JN). Pre-1987 models have a silver valve cover with ribbed design; post-1987 units use flat black covers. Critical differentiation from 2.0L inline-five: JN features Bosch K-Jetronic fuel distributor and 2,226 cc displacement. Service parts require model-year verification - fuel distributors and ECU units are not interchangeable between pre- and post-facelift variants due to emissions calibration differences (Audi SIB 07-10-01).
The JN's primary reliability risk is fuel distributor degradation, with elevated incidence in vehicles with extended service intervals. Internal Audi field reports from 1989 indicated a notable number of units requiring K-Jetronic rebuilds before 120,000 km, while UK DVLA inspection data shows increased emissions-related failures in high-mileage examples. Poor fuel quality and lack of maintenance exacerbate wear, making fluid quality and service adherence critical.
Analysis derived from Audi technical bulletins (1985-1990) and UK DVLA failure statistics (1985-1995). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about AUDI JN.
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AUDI Official Site
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
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VCA Certification Portal
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