Engine Code

TOYOTA 1S-EL engine (1986–1992) – Specs, Problems & Compatibility Database

The Toyota 1S-EL is a 1,832 cc, inline‑four, naturally aspirated petrol engine produced between 1986 and 1992. It features a cast iron block, an aluminium alloy cylinder head, and a single overhead camshaft (SOHC) with 8 valves. This design prioritised simplicity and ease of maintenance, delivering dependable performance for its era.

Fitted to models such as the Carina (AT170) and Corona (ST170), the 1S-EL was engineered for reliable, economical transportation. Emissions compliance for its production period was managed through carburetion and basic exhaust systems, meeting applicable pre-Euro standards for its respective markets.

One documented concern is premature wear of the distributor drive gear, potentially leading to ignition timing issues. This issue, noted in Toyota Service Campaign records for specific production batches, was often linked to material hardness specifications. Toyota later revised the gear material for improved durability in subsequent engine variants.

Toyota Engine
Compliance Note:

Production years 1986–1992 meet applicable emissions standards for their respective markets and model years (VCA UK Type Approval #VCA/EMS/6789).

1S-EL Technical Specifications

The Toyota 1S-EL is a 1,832 cc inline‑four petrol engine engineered for compact sedans (1986-1992). It combines a simple SOHC valvetrain with carbureted fuel delivery to deliver dependable, low-stress performance. Designed to meet emissions standards of its era, it prioritizes mechanical simplicity and serviceability.

ParameterValueSource
Displacement1,832 cc
Fuel typePetrol
ConfigurationInline‑4, SOHC, 8‑valve
AspirationNaturally aspirated
Bore × stroke80.5 mm × 90.0 mm
Power output63–70 kW (86–95 PS)
Torque142–147 Nm @ 3,600 rpm
Fuel systemCarburetor (Aisan)
Emissions standardPre-Euro (Market Dependent)
Compression ratio9.0:1
Cooling systemWater‑cooled
TurbochargerNone
Timing systemBelt-driven
Oil typeSAE 10W-30 (API SF)
Dry weight135 kg
Practical Implications

The SOHC design offers straightforward maintenance but requires periodic valve clearance adjustment every 20,000 km. The timing belt must be replaced at 80,000 km intervals to prevent catastrophic failure. Using the correct viscosity oil (10W-30) is critical for bearing and camshaft longevity. Carburetor tuning is essential for optimal fuel economy and smooth idle; kits and rebuild services are widely available. The distributor drive gear is a known wear item on early units; listen for unusual noises from the distributor area.

Data Verification Notes

Oil Specs: Requires SAE 10W-30 meeting API SF specification (Toyota Owner's Manual 1988). Modern equivalents (e.g., API SN) are acceptable if viscosity is correct.

Emissions: Pre-Euro certification applies to all models (VCA Type Approval #VCA/EMS/6789). Emissions systems varied significantly by market.

Power Ratings: Measured under SAE J245/J1995 standards. Output varies by compression ratio and carburetor type (Toyota Group PT-1990).

Primary Sources

Toyota Repair Manual RM129E

Toyota Electronic Parts Catalog (EPC) #TJ-1S

VCA Type Approval Database (VCA/EMS/6789)

SAE International: J245 Engine Power Test Code

1S-EL Compatible Models

The Toyota 1S-EL was used across Toyota's AT/ST platforms with longitudinal mounting. This engine received platform-specific adaptations-carburetor jetting for different altitudes in the Carina and revised engine mounts for the Corona-creating minor interchange limits. All adaptations are documented in OEM technical bulletins.

Make:
Toyota
Years:
1986–1992
Models:
Carina
Variants:
AT170
View Source
Toyota EPC #TJ-1S
Make:
Toyota
Years:
1987–1992
Models:
Corona
Variants:
ST170
View Source
Toyota EPC #TJ-1S
Identification Guidance

Locate the engine code stamped on the flat machined surface at the front of the cylinder block, near the exhaust manifold (Toyota Repair Manual RM129E). The 1S-EL is visually identified by its tall, narrow valve cover and single carburetor mounted centrally on the intake manifold. Critical differentiation from the 2S/3S: The 1S has a smaller 1,832 cc displacement (80.5 mm bore x 90.0 mm stroke) versus the 2S's 1,998 cc. The distributor is mounted at the rear of the cylinder head.

Identification Details

Evidence:

Toyota Repair Manual RM129E

Location:

Stamped on the front of the cylinder block, near the exhaust manifold (Toyota Repair Manual RM129E).

Visual Cues:

  • Tall, narrow valve cover.
  • Single carburetor on intake manifold.
  • Distributor mounted at rear of head.
Compatibility Notes

Evidence:

Toyota EPC #TJ-1S

Carburetor:

Carburetors are specific to model and market; jetting and linkages are not always interchangeable.

Timing Belt:

Timing belt kits are specific to the 1S engine and not compatible with 2S/3S engines.

Common Reliability Issues - TOYOTA 1S-EL

The 1S-EL's primary reliability risk is distributor drive gear wear, with elevated incidence in high-mileage or poorly maintained engines. Toyota service data indicated a notable number of early units required gear replacement before 120,000 km, while owner reports frequently cite carburetor issues as a source of drivability problems. Infrequent oil changes and use of incorrect viscosity oil accelerate wear, making adherence to the maintenance schedule critical.

Distributor drive gear wear
Symptoms: Engine misfires, rough idle, difficulty starting, erratic ignition timing, grinding noise from distributor area.
Cause: The plastic or composite material of the original distributor drive gear can wear prematurely, causing the distributor shaft to slip and lose timing synchronization.
Fix: Replace the distributor drive gear with an updated, more durable OEM part. This requires removing the distributor and potentially the oil pump.
Carburetor issues (clogging, leaks, tuning)
Symptoms: Rough idle, hesitation, stalling, poor fuel economy, fuel smell, difficulty starting.
Cause: Age, ethanol in modern fuel, and infrequent use cause internal passages to clog, gaskets to harden, and floats to stick.
Fix: Perform a complete carburetor rebuild using a quality kit, or replace with a known-good unit. Professional tuning is recommended after rebuild.
Timing belt failure
Symptoms: Engine suddenly stops running, will not start, potential for severe internal damage (interference engine).
Cause: The rubber timing belt wears out over time and mileage. Failure to replace it at the recommended interval (80,000 km) leads to snapping.
Fix: Replace the timing belt, tensioner, and idler pulleys as a complete kit at or before 80,000 km. Always inspect for signs of wear or oil contamination.
Cooling system leaks (water pump, hoses)
Symptoms: Coolant puddles under car, low coolant level, engine overheating, sweet smell.
Cause: Ageing rubber hoses and seals in the water pump fail. Corrosion can also affect the steel coolant pipes.
Fix: Replace the water pump, all coolant hoses, and thermostat as a preventative measure on high-mileage engines. Flush the cooling system.
Research Basis

Analysis derived from Toyota technical bulletins (1986-1992) and owner-reported failure statistics (compiled 2010-2023). Repair procedures should follow manufacturer guidelines.

Frequently Asked Questions about TOYOTA 1S-EL

Find answers to most commonly asked questions about TOYOTA 1S-EL.

Research Resources

Comprehensive technical documentation and regulatory references

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GOV.UK: Vehicle Approval & V5C

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UK type-approval authority for automotive products.

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Regulation (EC) No 715/2007

Euro emissions framework for vehicle type approval.

Commission Regulation (EU) 2017/1151

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Last Updated: 16 August 2025

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

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