DE9 - Perform Fuel Composition Test

This test is designed to determine the percentage of fuel methanol in the fuel. Use Rotunda FFV Fuel Test Kit 014-00770 or equivalent to test the fuel. The kit contains the following materials:

- Fuel drain hose assembly.

- Fuel pump jumper wire assembly.

- One beaker.

- One 25 ml graduated cylinder.

- One 5.71 liter gas can.

- Key "OFF".

- Powertrain Control Module (PCM) sensor connected.

- Breakout box installed, PCM connected.

- Fill the beaker with more than 4 ml of clean water.

- Place the hose end of the fuel drain hose assembly in the gas can.

- Connect the fuel drain hose assembly to the fuel pressure relief valve on the cold start injector. Turn the connector clockwise to tighten. Turn ON/OFF valve clockwise to open.

Vehicle Self-Test Connector:

- Connect the fuel pump jumper wire assembly to the vehicle Self-Test connector, refer to the illustration.

- Key "ON".

- Depress the jumper switch to the "ON" position and allow slightly more than 20 ml of fuel to drain into the gas can.

- Pour exactly 20 ml of fuel into the 25 ml graduated cylinder.

- Pour enough water from the beaker into the 25 ml graduated cylinder to bring the total volume to 24 ml.

- Insert the stopper plug into the opening of the 25 ml graduated cylinder and hold the stopper firmly in place (to prevent harmful spillage and escape of vapor) as you shake the cylinder to mix water and fuel. Allow liquid to stand and separate.

- After three minutes, the methanol and water will mix together and settle to the bottom of the cylinder. The gasoline will rise to the top.


- Note the point on the scale on the side of the 25 ml graduated cylinder where the methanol/water mixture and gasoline meet. The amount of fuel methanol is determined from the following equation:

Percent methanol (%M) = (A-4) X 5; where "A" equals the scale reading on the side of the graduated cylinder.

Calculate and record this value for use later in test step DE10.

Gasoline/Methanol Percentage Test:

Example: If the scale reading is 14 ml, then the percentage of methanol in the fuel mixture Is, (14 - 4) X 5 which equals 50. Therefore, the percentage of methanol in the fuel mixture is 50 (M50). See illustration.

NOTE: This test is accurate to +/-10%.

- Pour the contents of the 25 ml graduated cylinder into the fuel filler of the vehicle.

- Gasoline and water will separate. However, if the fuel does not appear to separate, then the fuel is either 100 percent methanol or a mixture of methanol and water.

- Pour any remaining fuel in the gas can back into the vehicle. Go to DE10. DE10 - Compare Methanol Percentage to Sensor Response