Diagnostic Notes

Diagnosis by Symptom is used to find the correct test procedure for a given symptom. Possible Cause and Actions within this section are "Fuel Related" only. Verify correct system application to ensure that vehicle has the given component. Always use Flow of Diagnosis for proper testing sequence.

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.

- Problems may be due to fuel system corrosion and subsequent fuel filter plugging, deterioration of rubber components and/or air/fuel mixture leaning.

- Various types and concentrations of alcohols are used in commercial fuel; some are more detrimental to fuel system components than others. If an excessive amount of alcohol in the fuel system is suspected as the cause of a driveability condition, refer to Alcohol-In-Fuel Test. Testing and Inspection

FUEL TYPES
Methyl Tertiary-Butyl Ether (MTBE)
Fuel containing Methyl Tertiary-Butyl Ether (MTBE) may be used if there is no more than 15% alcohol by volume.

Ethanol
Fuel containing ethanol (ethyl or grain alcohol) may be used if there is no more than 10% ethanol by volume.

Methanol
Fuel containing methanol (methyl or wood alcohol) may be used if there is no more than 5% methanol by volume. Use of fuel (gasohol) that contains more than 5% methanol can corrode metal fuel system components and damage plastic and rubber parts.


PRE-CHECKS:

1. Check for adequate fuel supply in fuel tank. Do not rely on fuel gauge!

2. Verify battery is fully charged.

3. Verify fuse/fuse link integrity.

4. Inspect all hoses, fuel lines, and connections for fuel leaks, kinks and proper routing.

5. Verify correct fuel type and quality.

6. Check TSB's for fuel system design updates.