VDO ALAS Adjustable Fuel Sender User Manual

1. Introduction

The VDO ALAS Adjustable Fuel Sender is a precision instrument designed for accurate measurement of fuel levels in various tank configurations. This sender is adjustable to accommodate tank depths ranging from 6-3/4 inches to 23 inches and provides a resistance output of 10-184 Ohms, making it compatible with a wide range of fuel gauges. This manual provides comprehensive instructions for the safe installation, proper operation, and routine maintenance of your VDO fuel sender to ensure reliable performance.

2. Safety Information

Always adhere to the following safety precautions when installing or servicing the fuel sender:

• Disconnect Power: Before beginning any work on the fuel system, always disconnect the vehicle's or vessel's battery to prevent electrical shorts and accidental activation.
• Ventilation: Ensure adequate ventilation in the work area to disperse fuel vapors, which are highly flammable.
• No Open Flames: Never work near open flames, sparks, or other ignition sources when handling fuel or working on fuel system components.
• Personal Protective Equipment: Wear appropriate personal protective equipment, including safety glasses and gloves, to protect against fuel exposure and potential injuries.
• Fuel Spills: Have absorbent materials readily available to clean up any fuel spills immediately. Dispose of contaminated materials properly.
• Professional Installation: If you are unsure about any part of the installation process, seek assistance from a qualified professional.

3. Product Components

The VDO ALAS Adjustable Fuel Sender assembly includes the following main components:

• Fuel Sender Unit (main body with electrical connections)
• Adjustable Float Arm
• Fuel Float
• Mounting Gasket
• Mounting Plate (with bolt holes)

Figure 3.1: Overview of the VDO ALAS Adjustable Fuel Sender components. The image displays the main sender unit, the long adjustable float arm with a white float at its end, a circular mounting plate with multiple holes, and a black rubber gasket.

4. Setup and Installation

Proper installation and adjustment are crucial for accurate fuel level readings. Follow these steps carefully:

4.1. Pre-Installation Steps

1. Measure Tank Depth: Accurately measure the depth of your fuel tank from the mounting surface to the bottom. The sender is adjustable for tanks between 6-3/4 inches (17.1 cm) and 23 inches (58.4 cm).
2. Adjust Float Arm: The float arm must be adjusted to match your tank's depth. The arm can be carefully bent to ensure the float reaches the bottom of the tank when empty and the top when full, without hitting the tank walls or bottom. Ensure the float has full range of motion.
3. Prepare Mounting Surface: Clean the fuel tank's mounting surface thoroughly, removing any debris, old gasket material, or corrosion.

4.2. Installation Procedure

1. Apply Gasket: Place the new mounting gasket onto the fuel tank's mounting flange.
2. Insert Sender: Carefully insert the VDO ALAS fuel sender into the tank opening, ensuring the float arm and float are positioned correctly and can move freely.
3. Secure Mounting Plate: Align the sender's mounting plate with the bolt holes on the tank flange. Secure the sender using appropriate fasteners (not included) and tighten them evenly to create a leak-proof seal. Do not overtighten.
4. Electrical Connections:
   • Connect the sender's signal wire to the fuel gauge's input terminal.
   • Connect the sender's ground wire to a reliable chassis or battery ground point. Ensure a clean, secure connection for accurate readings.
5. Reconnect Battery: Once all connections are secure and verified, reconnect the vehicle's or vessel's battery.

5. Operating Instructions

The VDO ALAS Adjustable Fuel Sender operates by varying its electrical resistance based on the fuel level. As the fuel level changes, the float moves the arm, which in turn changes the resistance of the sender unit. This resistance change is then interpreted by a compatible fuel gauge, which displays the current fuel level.

• Compatibility: Ensure your fuel gauge is designed to work with a 10-184 Ohm input sender for accurate readings.
• Initial Check: After installation, fill the fuel tank and observe the gauge reading. Then, if possible, drain the tank to verify the empty reading. This helps confirm proper installation and adjustment.
• Normal Operation: The sender will continuously provide fuel level data to the gauge as long as the system is powered.

6. Maintenance

The VDO ALAS Adjustable Fuel Sender is designed for long-term reliability with minimal maintenance. However, periodic inspection can help ensure continued accurate performance:

• Visual Inspection: Annually inspect the sender unit, float arm, and electrical connections for signs of corrosion, damage, or wear.
• Float Arm Movement: Ensure the float arm moves freely without any obstruction or binding.
• Electrical Connections: Check that all electrical connections are clean, tight, and free from corrosion. Loose or corroded connections can lead to inaccurate readings.
• Gasket Integrity: Inspect the mounting gasket for any signs of cracking, drying, or leaks. Replace if necessary.

7. Troubleshooting

If you experience issues with your VDO ALAS Adjustable Fuel Sender, consider the following troubleshooting steps:

If the problem persists after attempting these solutions, it may indicate a faulty component (sender or gauge) or a more complex electrical issue. Consult a qualified technician.

8. Technical Specifications

9. Warranty Information

The VDO ALAS Adjustable Fuel Sender comes with a manufacturer's warranty. For specific details regarding the warranty period, coverage, and claims process, please refer to the warranty documentation included with your product packaging. Alternatively, you may visit the official VDO website or contact their customer support directly.

10. Customer Support

For technical assistance, product inquiries, or support with installation and troubleshooting beyond the scope of this manual, please contact VDO customer support. You can typically find contact information on the official VDO website or through your product retailer.

When contacting support, please have your product model number (226-001) and any relevant purchase information readily available.