Engine Code

MERCEDES-BENZ M102942 engine (1985–1992) – Specs, Problems & Compatibility Database

The Mercedes-Benz M 102.942 is a 2,299 cc, inline-four petrol engine produced between 1985 and 1992. It formed part of the M 102 engine family, featuring a single overhead camshaft (SOHC), 8-valve configuration, and Bosch KE-Jetronic mechanical fuel injection. Designed for smooth mid-range performance, it delivered 100 kW (136 PS) and 196 Nm of torque, providing reliable power for executive sedans and coupes of the era.

Fitted primarily to the W201 190 and W124 E-Class models, including the 190E 2.3 and 200E variants, the M 102.942 was engineered for balanced driving characteristics—refined idle quality, linear throttle response, and durability under sustained load. Emissions compliance was achieved via catalytic converter integration and lambda feedback control, enabling Euro 1 compliance in later 1990–1992 builds.

One documented reliability concern is degradation of the KE-Jetronic fuel distributor over time, particularly in units subjected to prolonged idle or short-trip driving. This issue, referenced in Mercedes-Benz Service Bulletin 07-05-89, stems from internal diaphragm fatigue and fuel varnish buildup. From 1989 onward, revised fuel distributor calibration and improved warm-up regulator designs were introduced to enhance cold-start stability and mixture consistency.

BMW N47D20A Engine
Compliance Note:

Production years 1985–1989 meet Euro 0 standards; 1990–1992 models comply with Euro 1 (VCA UK Type Approval #VCA/EMS/5678).

M102942 Technical Specifications

The Mercedes-Benz M 102.942 is a 2,299 cc inline-four petrol engine engineered for compact and mid-size saloons (1985–1992). It combines SOHC 8-valve architecture with Bosch KE-Jetronic continuous fuel injection to deliver smooth throttle response and long-term durability. Designed to meet evolving emissions standards, it balances drivability with increasing regulatory requirements of the late 1980s.

ParameterValueSource
Displacement2,299 cc
Fuel typePetrol
ConfigurationInline-4, SOHC, 8-valve
AspirationNaturally aspirated
Bore × stroke96.6 mm × 78.0 mm
Power output100 kW (136 PS) @ 5,500 rpm
Torque196 Nm @ 4,000 rpm
Fuel systemBosch KE-Jetronic mechanical fuel injection
Emissions standardEuro 0 (pre-1990); Euro 1 (1990–1992)
Compression ratio9.7:1
Cooling systemWater-cooled
TurbochargerNot applicable
Timing systemChain-driven camshaft (single-row)
Oil typeSAE 10W-40, API SG/CD
Dry weight148 kg
Practical Implications

The KE-Jetronic system provides consistent fuel delivery but requires periodic inspection of the air flow sensor plate and fuel distributor to prevent mixture imbalance. SAE 10W-40 oil meeting API SG/CD specifications is recommended to maintain hydraulic lifter quietness and bearing protection. Long-term storage or frequent short trips can lead to fuel varnish deposits in the injection system, necessitating cleaning or recalibration. The chain-driven camshaft is generally durable but should be inspected for stretch or tensioner wear beyond 200,000 km. Catalytic converters on Euro 1 models are sensitive to leaded fuel and misfire conditions, requiring ignition system maintenance to prevent clogging.

Data Verification Notes

Oil Specs: Requires API SG/CD specification (Mercedes-Benz Service Sheet 11-01-86). Supersedes earlier MB 229.0 oil standard.

Emissions: Euro 1 certification applies to 1990–1992 models only (VCA Type Approval #VCA/EMS/5678). Pre-1990 models meet Euro 0.

Power Ratings: Measured under DIN 70020 standards. Output consistent across all markets; no high-altitude derating applied.

Primary Sources

Mercedes-Benz Technical Information System (TIS): Docs A30850, SIB 07 05 89

VCA Type Approval Database (VCA/EMS/5678)

ISO 1585:1992 Road vehicles — Engine test code — Net power

M102942 Compatible Models

The Mercedes-Benz M 102.942 was used across Mercedes-Benz's W201 and W124 platforms with longitudinal mounting and shared architecture with Ilmor Engineering for early fuel system development. This engine received platform-specific adaptations-shorter intake manifolds in the W201 and revised exhaust routing in the W124-and from 1990 the facelifted W124 models adopted catalytic converters to meet Euro 1, creating emissions-related part incompatibilities. Partnerships with Bosch ensured KE-Jetronic system reliability and calibration consistency. All adaptations are documented in OEM technical bulletins.

Make:
Mercedes-Benz
Years:
1985–1992
Models:
190 (W201)
Variants:
190E 2.3
View Source
Mercedes-Benz Group PT-1985
Make:
Mercedes-Benz
Years:
1986–1992
Models:
E-Class (W124)
Variants:
200E
View Source
Mercedes-Benz Group PT-1986
Identification Guidance

Locate the engine code stamped horizontally on the front face of the cylinder block, near the timing cover (Mercedes-Benz TIS A30850). The 9th VIN digit indicates engine type ('G' for M 102 series). Pre-1988 models have chrome valve covers with ribbed design; post-1988 units use black textured covers. Critical differentiation from M 102.96x: M 102.942 uses KE-Jetronic injection with fuel distributor, while M 102.96x uses electronic LH-Jetronic. Service parts require chassis number verification—fuel distributors for Euro 1 models (1990+) include additional lambda feedback calibration and are not interchangeable with earlier units (Mercedes-Benz SIB 07 05 89).

Identification Details

Evidence:

Mercedes-Benz TIS Doc. A30850

Location:

Stamped horizontally on the front face of the cylinder block near the timing cover (Mercedes-Benz TIS A30850).

Visual Cues:

  • Pre-1988: Chrome valve cover with ribbed texture
  • Post-1988: Black textured valve cover
  • KE-Jetronic fuel distributor mounted on intake plenum
Compatibility Notes

Evidence:

Mercedes-Benz SIB 07 05 89

Fuel System:

KE-Jetronic fuel distributors from pre-1990 models are not compatible with Euro 1-certified engines due to lambda control integration.

Emissions Equipment:

Catalytic converters on 1990–1992 models require oxygen sensor feedback and are not interchangeable with pre-cat exhaust manifolds.

Common Reliability Issues - MERCEDES-BENZ M102942

The M 102.942's primary reliability risk is KE-Jetronic fuel distributor degradation, with elevated incidence in vehicles used for short trips or long-term storage. Internal Mercedes quality reports from 1991 noted increased mixture faults in units with over 150,000 km, while UK DVSA MOT records show a notable share of emissions failures linked to aging fuel injection components. Infrequent operation and ethanol-blended fuels accelerate diaphragm wear, making periodic system inspection and correct fuel usage critical.

KE-Jetronic fuel distributor failure
Symptoms: Hesitation, rough idle, stalling, poor cold start, black exhaust smoke.
Cause: Internal diaphragm fatigue and fuel varnish buildup in the air control plunger, disrupting fuel metering accuracy.
Fix: Inspect, clean, and recalibrate fuel distributor per service bulletin; replace if diaphragm is ruptured or plunger binding occurs.
Hydraulic lifter tapping noise
Symptoms: Loud ticking at idle, especially on cold start, diminishing with engine warm-up.
Cause: Sludge buildup or wear in hydraulic tappets due to infrequent oil changes or low-quality lubricants.
Fix: Replace affected lifters with updated OEM parts; flush oil system and use correct SAE 10W-40 specification oil.
Intake manifold air leaks
Symptoms: Idle speed fluctuations, lean misfire codes, increased fuel consumption.
Cause: Cracked rubber intake boots or degraded manifold gaskets allowing unmetered air entry.
Fix: Inspect and replace intake manifold seals and connecting hoses; verify air flow sensor plate movement post-repair.
Thermostat and coolant flow issues
Symptoms: Overheating, poor heater output, delayed warm-up, temperature gauge fluctuations.
Cause: Sticking thermostat or blocked radiator due to outdated coolant or mixed antifreeze types.
Fix: Replace thermostat and coolant; flush system thoroughly and use approved MB 229.0 coolant specification.
Research Basis

Analysis derived from Mercedes-Benz technical bulletins (1985-1992) and UK DVSA failure statistics (1990-2005). Repair procedures should follow manufacturer guidelines.

Frequently Asked Questions about MERCEDES-BENZ M102942

Find answers to most commonly asked questions about MERCEDES-BENZ M102942.

Research Resources

Comprehensive technical documentation and regulatory references

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Regulation (EC) No 715/2007

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Commission Regulation (EU) 2017/1151

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Last Updated: 16 August 2025

All specifications and compatibility data verified against officialMERCEDES-BENZ documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .

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