FUEL - INFORMATION ON GASOLINE - TIPS TO RESOLVE VOLATILITY RELATED DRIVEABILITY CONCERNS
Publication Date: DECEMBER 18, 1998
1985-1997 THUNDERBIRD 1986-1999 MUSTANG, TAURUS 1987-1999 ESCORT 1988-1994 TEMPO 1989-1997 PROBE 1990-1999 CROWN VICTORIA 1992-1993 FESTIVA 1995-1999 CONTOUR
1985-1997 COUGAR 1986-1992 MARK VII 1986-1999 SABLE 1987-1989 TRACER 1988-1994 TOPAZ 1988-1999 CONTINENTAL 1990-1999 GRAND MARQUIS, TOWN CAR 1991-1999 TRACER 1993-1998 MARK VIII 1995-1999 MYSTIQUE 1999 COUGAR
1986-1997 AEROSTAR 1987-1996 BRONCO 1989-1997 F SUPER DUTY, F-350 1989-1999 F-150, F-250 LD, RANGER 1991-1999 EXPLORER 1992-1999 ECONOLINE 1993-1999 VILLAGER 1995-1999 WINDSTAR 1997-1999 EXPEDITION, MOUNTAINEER 1998-1999 NAVIGATOR 1999 SUPER DUTY F SERIES
This TSB article is being republished in its entirety to expand vehicle model coverage and revise the text.
Some vehicles using winter blend fuels may exhibit a stall on start up and a no restart, hard start condition or a no start condition in unseasonably hot weather (greater than 27°C/80°F). These concerns may be related to fuel volatility from winter blend fuels during winter-spring and autumn-winter transitions and may result in a fuel pump vapor lock condition. This condition may appear to be a fuel pump failure but may be caused by winter blend fuel.
Refer to the following text for further information.
FUEL TANK ADDITIVES WILL NOT RESOLVE THESE CONCERNS BECAUSE VAPOR FORMS FROM CAVITATION WITHIN THE FUEL PUMP. FILLING THE TANK TO FULL MAY BE EFFECTIVE. ADVISE CUSTOMER TO USE THE RECOMMENDED OCTANE GRADE PER OWNER MANUAL AND NOT A HIGHER GRADE.
Explain to the customer that this concern may be due to a low tank level of winter blend fuel combined with unseasonably warm weather. Advise customer that filling the fuel tank to full may be effective in resolving this concern. Also, advise customer to use the recommended octane grade per their Owner Manual and not a higher grade.
Gasolines are seasonally adjusted, meaning they have higher volatility (vaporize easier) in the winter and lower volatility in the summer. Government mandates to improve air quality have resulted in significant changes to gasolines, such as the mandatory use of oxygenates (ethanol, methyl tertiary butyl ether (MTBE), and others) in the winter or the reduction of Reid Vapor Pressure (RVP) in the summer. The addition of oxygenates (especially ethanol) increases volatility while the reduction of RVP reduces volatility.
Gasoline distribution practices often do not allow branded marketers to have much control over their gasoline's volatility other than RVP. Oxygenate (e.g., ethanol, MTBE) use is more dependent on local gasoline markets, rather than specific marketers practice. Therefore, it is difficult to recommend specific brands to avoid volatility related complaints.