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Home >> Cadillac >> 2012 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 55 (Engine Controls - System & Component Tests - 2.2L) >> Fuel Systems (Gasoline) >> Alcohol/Contaminants-In-Fuel Diagnosis Using Special Tool >> Test Procedure
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Test Procedure

WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: The numbers in parenthesis in the text refer to numbered components in figures.
  1. Turn ON the Fuel Composition Tester (J 44175), or equivalent.
  2. Verify the fuel composition tester is operational by measuring the AC frequency output using a DMM. A frequency without a fuel sample in the test cell indicates that the tester is working correctly.
  3. Connect Fuel Pressure Gauge (J 34730-1A), or equivalent, to the fuel pressure connection, located on the fuel rail. See Figure.
  4. Close the bleed valve on the fuel pressure gauge.
  5. Place the bleed hose (1) of the fuel pressure gauge into the 100 ml beaker (2). See Fig 1.
  6. Command the fuel pump relay ON using a scan tool.
  7. Slowly open the bleed valve on the fuel pressure gauge, until an adequate fuel sample is obtained.
  8. If water appears in the fuel sample, clean the fuel system and replace the fuel in the vehicle.
    9. CAUTION: Do not allow any substances other than gasoline, ethanol/gasoline blends, air, or acetone into the test ports of the fuel composition tester. Contaminants in the fuel composition tester could result in misdiagnosis.
  9. Pour the fuel sample from the beaker (1) into the fuel composition tester (3), until the level of the fuel is at the top of each fuel test port (2). See Fig 2.
  10. Observe the diagnostic LEDs on the fuel composition tester. If the Red fuel diagnostic LED is illuminated, a fuel contamination condition exists.
  11. Measure the output frequency of the fuel composition tester.
  12. Subtract 50 from the reading on the DMM to obtain the percentage of alcohol in the fuel sample. See examples in FUEL COMPOSITION TEST EXAMPLES  table.
  13. If the fuel sample contains more than 10 percent ethanol, add gasoline to the fuel tank or replace the fuel in the vehicle.
Fig 1: Bleeding Fuel Into Beaker
G00196157Courtesy of GENERAL MOTORS CORP.
Fig 2: Pouring Test Sample Into Fuel Composition Tester
G00196158Courtesy of GENERAL MOTORS CORP.
FUEL COMPOSITION TEST EXAMPLES

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