Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Alcohol/Contaminants-In-Fuel Diagnosis (With Special Tool)
2007 Chevrolet Express 2500 V8-6.0LSECTION Alcohol/Contaminants-In-Fuel Diagnosis (With Special Tool)
Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)
Description
Water contamination in the fuel system may cause driveability conditions such as hesitation, stalling, no start, or misfires in one or more cylinders. Water may collect near a single fuel injector at the lowest point in the fuel injection system, and cause a misfire in that cylinder. If the fuel system is contaminated with water, inspect the fuel system components for rust or deterioration.
Ethanol concentrations of greater than 10 percent in non-blended gasoline, or greater than 85 percent with E85 blended gasoline for flexible fuel applications, can cause driveability conditions and may contribute to fuel system deterioration. Excessive ethanol concentrations can result in driveability conditions such as hesitation, lack of power, stalling, or a no start, and may contribute to fuel system corrosion, deterioration of fuel system components, and a restricted fuel filter.
Test Procedure
1. Test the fuel composition using J 44175 Fuel Composition Tester and J 44175-3 Instruction Manual.
2. If water appears in the fuel sample, perform the following steps:
1. Clean the fuel system. Refer to Fuel System Cleaning. Service and Repair
2. Replace the fuel filter if the vehicle is equipped with a serviceable fuel filter.
3. Subtract 50 from the reading on the DMM in order to obtain the percentage of alcohol in the fuel sample. Refer to the examples in the Fuel Composition Test Examples table.
4. If the non-blended gasoline fuel sample measures more than 15 percent ethanol, or if the E85 blended gasoline fuel sample measures more than 91 percent ethanol, add fresh, regular gasoline to the vehicle's fuel tank.
5. Test the fuel composition.
6. If additional testing indicates that the ethanol percentage is still more above 15 percent for a non-blended gasoline sample, drain and replace the vehicle's fuel. Refer to Fuel System Cleaning. If additional testing indicates that the E85 blended gasoline sample still measures above 91 percent, continue adding fresh, regular gasoline until the ethanol content measures 91 percent or less. Service and Repair
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.