Fuel - Recommended Use of Gasoline/Alcohol Blends

84isuzu01 SB84-02-002

Aug. 3, 1984

FUEL SYSTEM

USE OF GASOLINE/ALCOHOL BLENDS

Currently there is a great deal of controversy concerning gasoline/alcohol blends. Beginning with the 1985 model year, American Isuzu Motors, Inc. is taking the following official position on the use of gasoline/alcohol blended fuels.

Blends of unleaded gasoline and ethanol (grain alcohol) not containing over 10% ethanol may be used without affecting the Isuzu Limited Warranty. Should gasohol prove to be the cause of driveability problems, a return to unleaded gasoline is suggested.

Blends containing methanol (wood alcohol) are not authorized unless they also contain cosolvents and corrosion inhibitors. Do not use blends containing more than 5% methanol even if they contain cosolvents and corrosion inhibitors. Damage to fuel system components or driveability problems associated with the use of methanol may not be covered by the Isuzu Limited warranty.

Many problems are currently associated with the use of gasoline/alcohol blends. Evaporative emissions are significantly increased, often by over 100%. Fuel economy may be reduced, and driveability may suffer. As a result of the leaning effect of alcohol, greater potential exists for cold weather hesitation, stalling, and vapor lock.

The main cause of poor driveability is water contamination of the fuel. Contamination causes the fuel in the vehicle tank to separate into two (2) layers, with the water-saturated alcohol sinking below a gasoline-rich upper layer. Extreme driveability problems occur when this alcohol/water mixture reaches the engine. Even trace amounts of water (as little as 0.1 percent) may cause fuel separation. Solubility of alcohol in gasoline is further reduced by lower ambient temperatures.

Even though this policy relates specifically to 1985 and later model year vehicles, we recommend use of these guidelines for all previous Isuzu gasoline powered vehicles.