Detonation/Spark Knock

***UPDATED BY TSB #405489 DATED FEB. 20, 1989

Mazda recommends the use of UNLEADED REGULAR gasoline only, in all vehicles not equipped with a turbocharger, unless otherwise specified. Do not use, or recommend for use, any higher octane fuels. Starting, idle, and driveability problems may result. See factory Technical Service Bulletin #405489, titled "USE OF REGULAR UNLEADED GASOLINE".

Definition: A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening.

POSSIBLE CAUSE ACTION

Lean operating condition Check computer controls
Refer to Computers and Control Systems

Poor or contaminated fuel Check for excessive fuel alcohol content

Incorrect fuel pressure Check and adjust system pressure

Vacuum leak Inspect vacuum hoses for
proper routing and damaged lines
Check intake manifold and
throttle chamber base