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MOTRS

240Z / 260Z / 280Z

1969-1978 / Coupe / Japan

All 240Z / 260Z / 280Z problems All workshop issues
Common Engine

Fuel Injection Faults (280Z)

Symptoms

Hard starting (especially cold), rough idle, hesitation, rich or lean running, stalling. The engine management warning light may illuminate.

Cause

The Bosch L-Jetronic fuel injection system uses an airflow meter (AFM) with a mechanical flap that wears with age. The cold start injector and thermo time switch fail. Injector seals harden and leak. The electronic control unit (ECU) can develop dry solder joints. Wiring connectors corrode, creating intermittent faults.

Fix

Start with the basics: clean or replace the AFM ($200-500 used, very hard to source new), replace injector seals ($50-80 for a set), clean the cold start injector, test the thermo time switch, and inspect all wiring connectors for corrosion.

For a permanent solution, many owners convert to modern aftermarket EFI, a Haltech or Link ECU with new injectors eliminates all age-related injection issues and makes the engine far more tuneable.

Cost: $2,000-4,000 for a quality conversion.

Cost mentioned in fix
$200-500$50-80 for aCost: $2,000-4,000 for a

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Other known issues

Common Engine

SU Carburettor Wear and Tuning Issues (240Z, 260Z)

Poor idle, hesitation on acceleration, rich or lean running, black smoke, poor fuel economy, difficult starting. The engine may run well at some RPMs but poorly at others.
Critical Engine

Timing Chain Stretch

Rattling or slapping noise from the front of the engine, particularly on cold start. The noise may diminish as the engine warms but does not fully disappear.
Critical Engine

Head Gasket Failure

Coolant loss with no visible external leak. White smoke from the exhaust. Milky residue on the oil filler cap. Overheating. Coolant in the oil or oil in the coolant.
Common Engine

Valve Stem Seal Deterioration

Blue-grey smoke on startup (after the car has been sitting). Blue smoke on deceleration (lifting off the throttle after sustained acceleration). Oil consumption increases, typically 1L per 2,000-3,000 km.
Minor Rust

Structural Rust, Floors, Sills, Strut Towers

Perforations in the floor pans, sill (rocker panel) box sections, and front strut tower mounting points. In advanced cases, the floorboard flexes underfoot, the sills crumble when prodded, and the strut towers crack under suspension load.
Common Rust

Battery Tray Corrosion

The battery tray (right-hand side of engine bay on RHD cars) corrodes and eventually perforates. Rust spreads into the inner guard and firewall.
View all 17 240Z / 260Z / 280Z problems