Diagnostic Pre-Checks

This section is used to verify that the fuel itself is not the cause of any fuel related problems. By using an alternate fuel you could be causing a fuel system problem or driveablity symptom. The information in this section is FUEL RELATED ONLY. Always use the FLOW OF DIAGNOSIS for proper testing sequence. Always verify the fuel injection system and application to ensure that the vehicle is equipped with a given component.

PRE-CHECKS:

1. Check for adequate fuel supply in the tank. DO NO RELY ON THE FUEL GAUGE!
2. Inspect all hoses, fuel lines, and connections for fuel leaks, kinks, and proper routing.
3. Verify correct fuel type and quality.
4. Check TSB's for fuel system design or part updates.

NOTE: ALCOHOL-IN-FUEL

Alcohol-in-fuel can be detrimental to fuel system components and may cause driveability problems such as hesitation, lack of power, stall, no start, etc.
The problems may be due to fuel system corrosion and subsequent fuel filter clogging, deterioration of rubber components, and/or air/fuel mixture leaning.
Various types and concentrations of alcohols are used in commercial fuel. Some alcohols are more detrimental to fuel system components than others. If an excessive amount of alcohol in the fuel is suspected as the cause of a DRIVEABILITY condition, refer to ALCOHOL-IN-FUEL TEST. In this procedure, water is used to extract the alcohol from the fuel to determine amount of alcohol present in the fuel.

NOTE: FUEL TYPES

1. METHYL TERTIARY-BUTYL ETHER (MTBE)
Fuel containing MTBE may be used provided there is no more than 15% alcohol by volume.

2. ETHANOL
Fuel containing ethanol or grain alcohol may be used, provided there is no more than 10% alcohol by volume.

3. METHANOL
Fuel containing methanol or wood alcohol may be used provided there is no more than 5% alcohol by volume.