Replacing The Fuel Pump Relay In Your E250: Step-By-Step Guide

Replacing a fuel pump relay can be a complex process, but it's crucial for keeping your vehicle in good shape. The fuel pump relay acts as a switch that controls the fuel pump's power, and when it fails, your car won't start. This tutorial will guide you through the process of replacing the fuel pump relay in your E250, covering everything from locating the relay to testing your vehicle after the replacement. We'll also discuss some common symptoms of a failing fuel pump relay and provide tips for safely handling and inspecting the component.

Check for common symptoms of a failing fuel pump relay

The fuel pump relay is an important component of your car's fuel system. It is an electromagnetic switch that uses low current to control a higher current circuit. When the ignition is turned on, the fuel pump relay produces a humming noise. If you don't hear this, it could be a sign of a failing fuel pump relay. Here are some common symptoms of a failing fuel pump relay to watch out for:

• Engine Cranks But Doesn't Start: This is often the most common sign of a bad fuel pump relay. The engine will crank, but due to a lack of fuel, it won't start.
• Fuel Pump Runs Continuously: Although rare, the fuel pump relay can get stuck in the closed/on position, causing the fuel pump to run continuously, even when the key is out of the ignition.
• Illuminated Check Engine Light: The engine computer or powertrain control module (PCM) monitors the fuel pump relay. If it detects an issue, it turns on the check engine light and stores a diagnostic trouble code (DTC).
• Multiple Failed Start Attempts: Your vehicle may require multiple attempts to start, especially when the engine is cold. Over time, this issue may worsen until the vehicle won't start at all.
• Unexplained Battery Drainage: A fuel pump relay stuck in the closed/on position can cause the fuel pump to run even when the vehicle is turned off, draining the battery.
• Seasonal Starting Issues: Your vehicle may start fine during the warm months but refuse to start during colder months.
• Stalling: Your vehicle may start but stall after a few seconds or minutes. This could be related to the fuel pump relay or a thermal expansion issue inside the TIPM or other electrical components.

If you experience any of these issues, it is recommended to consult a qualified mechanic or refer to your vehicle's owner's manual for specific guidance on replacing the fuel pump relay.

Disconnect the battery

Disconnecting the battery is the sixth step in the process of replacing the fuel pump relay in an E250. Here is a detailed, step-by-step guide on how to do it safely:

Turn Off the Engine

Before you begin, make sure that the engine is turned off and the keys are removed from the ignition. Disconnecting the battery with the engine running could be dangerous and cause bodily injury and vehicle damage.

Locate the Battery and Terminals

The battery is usually located in the engine compartment, but in some vehicles, it may be in the trunk or under the rear seat. Consult your vehicle's manual to determine the exact location. The negative terminal should display a negative symbol (-) and usually has a black cable, while the positive terminal should have a positive symbol (+) and is usually red.

Disconnect the Negative Terminal

Disconnect the negative terminal first to prevent any electrical shorts. Use a wrench to loosen the nut or bolt securing the terminal. Then, carefully lift the cable off the battery post and set it aside, ensuring it doesn't touch any metal surface.

Disconnect the Positive Terminal

Repeat the same process as above but for the positive terminal. Again, make sure that the positive and negative terminals do not touch each other or any metal surface. You may need to isolate the positive cable end by wrapping it in a non-conductive material, such as a towel.

Loosen and Remove the Battery Hold-Down

The battery hold-down keeps the battery in place while driving. Locate the fasteners and loosen or remove them with your wrench, then carefully remove the battery. Be mindful of its weight, as car batteries can weigh 40 pounds or more. Lift with your legs to avoid back injury. Place the battery on a dry, flat surface.

By following these steps, you will have successfully disconnected the battery in your E250. Remember to always put safety first and consult your owner's manual for specific instructions related to your vehicle model.

Locate the fuel pump relay

To locate the fuel pump relay in your Ford E250, you will need to find the fuse box. The fuse box is usually located in the engine compartment, but in some cars, it may be elsewhere.

Once you have located the fuse box, follow these steps:

• Open the fuse box by removing the cover. Note that some fuse boxes are held on with hex screws or bolts and will require a ratchet to remove them, while others are held on with clips.
• Locate the fuel pump relay inside the fuse box. You can use the diagram on the fuse box cover to identify the correct relay. If there is no diagram, refer to your owner's manual for the engine compartment fuse box diagram. The owner's manual will typically list numbers next to the fuel pump relay, which you can use to identify the correct fuse on the fuse box.
• Once you have identified the fuel pump relay, pay attention to how it is positioned as the new one will need to be installed in the same way.
• If necessary, use a pair of needle-nose pliers to carefully remove the fuel pump relay from the fuse box.

Remove and replace the fuel pump relay

Step 1: Turn the ignition key to the run position and listen for the fuel pump to actuate. You should also listen for any buzzing or clicking noises coming from the fuel pump relay.

Step 2: Start the engine and check the oil pressure. Some vehicles will only have an oil light indicator; when the indicator light goes out, there will be oil pressure.

Step 3: Park your vehicle on a flat, hard surface. Make sure that the transmission is in park for automatics or in first gear for manuals.

Step 4: Place wheel chocks around the front tires. Engage the parking brake to lock the rear tires from moving.

Step 5: Install a nine-volt battery saver into your cigarette lighter to keep your computer live and your settings current.

Step 6: Open the vehicle's hood and disconnect the battery. Take the ground cable off the battery's negative post to disable the power to the fuel pump and sending unit.

Step 7: Locate the fuse box in the engine compartment and remove the cover. You may need to use a ratchet to remove hex screws or bolts holding the fuse box in place.

Step 8: Using the diagram on the fuse box cover, locate the fuel pump relay. If there is no diagram, refer to your owner's manual for the engine compartment fuse box diagram.

Step 9: Remove the fuel pump relay from the fuse box, paying attention to how it comes out so that you can insert the new one in the same way. You may need to use a pair of needle-nose pliers to do this.

Step 10: Install the new fuel pump relay into the fuse box in the same orientation as the old one. Put the fuse box cover back on, snapping it into place.

Step 11: Remove and replace the fuel cap on the fuel tank to ensure a good seal and proper pressurization.

Step 12: Reconnect the ground cable to the battery's negative post and remove the nine-volt battery saver. Ensure that the battery connection is good and tight.

Step 13: Turn the ignition key on and listen for the fuel pump to activate. Turn the ignition off once the pump stops making noise, then turn the key on again and listen for the fuel pump relay to buzz or click.

Additional Notes:

• You may need to cycle the ignition key on and off 3 to 4 times to ensure the fuel rail is full before starting the engine.
• Most modern-day vehicles will not start up until oil pressure has built up.
• If you did not use a nine-volt battery saver, you will need to reset all the settings in your vehicle, such as your radio, electric seats, and mirrors.

Test the vehicle

Once you've replaced the fuel pump relay, it's important to test the vehicle to ensure that the new relay is working as it should. Here are some detailed instructions on how to do that:

Step 1: Turn on the ignition and listen for the fuel pump to activate

Turn the ignition key to the "run" position and listen carefully. You should be able to hear the fuel pump actuate. Pay attention to any buzzing or clicking noises coming from the fuel pump relay.

Step 2: Start the engine and check for oil pressure

Start the engine and look for signs of oil pressure. Depending on your vehicle, there may only be an oil light indicator. If so, wait for the indicator light to go out, which indicates that there is oil pressure.

Step 3: Drive the vehicle and listen for unusual noises

Take the vehicle for a test drive and pay close attention to any unusual noises coming from the fuel pump or fuel pump relay. Accelerate the engine quickly to ensure that the fuel pump is working correctly.

Step 4: Monitor the dashboard for any engine lights

Keep an eye on the dashboard during your test drive. If the engine light comes on, it could indicate further issues with the fuel pump assembly or a possible electrical problem within the fuel system. If the problem persists, consider seeking help from a certified technician.

Step 5: Check for unusual smells

Be aware of any unusual smells during your test drive. If you notice a strange smell, it could indicate an issue with the fuel pump or fuel system.

Step 6: Re-test the relay (optional)

If you still suspect an issue with the fuel pump relay, you can try re-testing it using a multimeter. Turn off the vehicle and remove the key from the ignition. Locate the fuel pump relay in the fuse box and remove it. Clean the relay prongs with a wire brush if necessary. Then, follow the testing procedure outlined in the previous steps, which includes checking the circuit diagram on the relay, setting your multimeter to the ohm setting, and attaching jumper wires to the terminals of your vehicle's battery and the relay.

Frequently asked questions