Adding Equipment to the Outside of Your Vehicle- Page 274

6-4

Be sure the posted octane is at least 87. If the octane is
less than 87, you may get a heavy knocking noise when
you drive. If it’s bad enough, it can damage your engine.

If you’re using fuel rated at 87 octane or higher and 
you hear heavy knocking, your engine needs service.
But don’t worry if you hear a little pinging noise when
you’re accelerating or driving up a hill. That’s normal,
and you don’t have to buy a higher octane fuel to get 
rid of pinging. It’s the heavy, constant knock that means
you have a problem.

If your vehicle is certified to meet California Emission
Standards (indicated on the underhood emission control
label), it is designed to operate on fuels that meet
California specifications. If such fuels are not available
in states adopting California emissions standards, 
your vehicle will operate satisfactorily on fuels meeting
federal specifications, but emission control system
performance may be affected. The malfunction indicator
lamp on your instrument panel may turn on and/or your
vehicle may fail a smog

-

check test. See “Malfunction

Indicator Lamp” in the Index. If this occurs, return to
your authorized Buick dealer for diagnosis to determine
the cause of failure. In the event it is determined that the
cause of the condition is the type of fuels used, repairs
may not be covered by your warranty.

Some gasolines that are not reformulated for low
emissions may contain an octane

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enhancing additive

called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask your service station operator whether or 
not the fuel contains MMT. General Motors does not
recommend the use of such gasolines. If fuels containing
MMT are used, spark plug life may be reduced and your
emission control system performance may be affected.
The malfunction indicator lamp on your instrument
panel may turn on. If this occurs, return to your
authorized Buick dealer for service.

To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent deposits from forming in your engine and 
fuel system, allowing your emission control system 
to function properly. Therefore, you should not have 
to add anything to the fuel. In addition, gasolines
containing oxygenates, such as ethers and ethanol, and
reformulated gasolines may be available in your area to
contribute to clean air. General Motors recommends that
you use these gasolines, particularly if they comply with
the specifications described earlier.