Supra (A70)

1986-1993 / Coupe / Japan

All Supra (A70) problems All workshop issues

Common Fuel System

Injector Failure/Inadequacy

Symptoms

Rough idle, misfiring under load, lean conditions (visible on wideband O2 gauge), and poor fuel economy.

Cause

On stock cars, the original injectors (260 cc on 7M-GTE) clog from age and contaminated fuel. On modified cars, the stock injectors are undersized for the increased airflow and can't deliver enough fuel at high RPM/boost.

Fix

For stock engines, professional injector cleaning and flow testing is the first step ($15-20 per injector).

If the injectors are beyond cleaning, replace with new OEM-spec units.

For modified engines, common upgrades: 440 cc injectors for mild builds (up to ~350 hp), 550 cc RC Engineering injectors for moderate builds (350-500 hp), and 1,000 cc injectors for big-power builds.

Any injector change requires a retune.

Cost mentioned in fix

$15-20 per injector

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Other known issues

Common Engine, 7M-GTE (Turbo)

Head Gasket Failure

The head gasket blows, allowing coolant into the combustion chambers and/or oil passages. White smoke from the exhaust, coolant loss without visible external leak, overheating under boost, milky oil on the filler cap, and bubbles in the coolant overflow tank. In severe cases, hydrolock (coolant filling a cylinder and bending a connecting rod on startup).

Critical Engine, 7M-GTE (Turbo)

Low Oil Pressure at Idle

Oil pressure drops below 10 psi at hot idle. The factory oil pressure warning light may flicker or illuminate at idle, particularly in traffic on hot days. The engine may develop bearing noise (deep knocking from the bottom end).

Common Engine, 7M-GTE (Turbo)

CT-26 Turbo Failure

Loss of boost pressure, excessive oil smoke (blue/grey) on startup or deceleration, whistling or grinding noises from the turbo, and oil in the intercooler piping.

Critical Engine, 7M-GTE (Turbo)

Cooling System Inadequacy Under Boost

Coolant temperature climbs rapidly under sustained boost, particularly in traffic or on hot days. The temperature gauge sits higher than normal and doesn't recover quickly.

Common Engine, 7M-GTE (Turbo)

Fan Clutch Wear

The engine runs hotter than normal, particularly at low speeds and idle. The cooling fan doesn't seem to pull much air through the radiator.

Critical Engine, 7M-GE (Naturally Aspirated)

Head Gasket Failure (Less Common)

View all 17 Supra (A70) problems