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Home >> Chevrolet >> 2003 >> Impala Base, 3.4 E >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System & Component Testing - 3.4L >> Fuel Systems >> Alcohol/Contaminants-In-Fuel Diagnosis With Special Tool >> Test Procedure

Test Procedure

  1. Test the fuel composition using Fuel Composition Tester (J 44175) and Instruction Manual (J44175-3), or equivalents.
  2. If water appears in the fuel sample, clean the fuel system. Go to FUEL SYSTEM CLEANING  and/or replace the fuel filter as necessary.
  3. Subtract 50 from the reading on the DMM to obtain the percentage of alcohol in the fuel sample. See the examples in the FUEL COMPOSITION TEST EXAMPLES  table.
  4. If the fuel sample contains more than 15 percent ethanol, add fresh, regular gasoline to the vehicle's fuel tank.
  5. Test the fuel composition.
  6. If testing shows the ethanol percentage is still more than 15 percent, replace the fuel in the vehicle. Go to FUEL SYSTEM CLEANING .
FUEL COMPOSITION TEST EXAMPLES

Example Frequency - Hz Subtract 50 Ethanol Percent
A 50 -50 0
B 65 -50 15
C 129 -50 79