Fuel Pump Power: Replacing The 2002 F350's Heart

The fuel pump relay in a 2002 Ford F-350 is located in the main fuse panel under the hood. The relay is integrated into the interior fuse box and is not separately serviceable. The fuse box must be replaced if the relay has failed, which is the most common cause of a non-functional fuel pump. The fuel pump relay losing power will cause the pump to reset and reboot, which can often solve small problems.

Fuel pump relay location

The fuel pump relay is located in the central junction box, or the fuse box, which is under the dash on the driver's side. The relay is soldered into the board and cannot be replaced without soldering skills and equipment. The relay usually burns out due to continuous use, so it may need to be replaced.

The fuel pump relay is powered by fuse #40 in the interior fuse box. To check if the relay has failed, check for power on both sides of the fuse when cranking the engine. If there is no power, then the relay has failed and the fuse box will need to be replaced.

For a 1993 Ford F-350, the fuel pump relay is located on the inside left front fender, in the square plastic box. It is also possible that it is located in the power distribution box by the air cleaner, relay #2.

For a 1991 Ford F350, the fuel pump relay is located on the LH fender apron, on a relay assembly, next to the EEC relay, which is brown.

No power to the fuel pump

If you are experiencing no power to the fuel pump in your 2002 F350, there are several potential causes and solutions.

Firstly, it is important to check the fuel pump relay and fuse. The fuel pump relay is integrated into the interior fuse box and is not serviceable separately. If the relay has failed, the entire fuse box may need to be replaced. To determine if the relay is faulty, check for power on both sides of the fuse when cranking the engine. If there is no power when cranking, the relay has likely failed.

Additionally, the inertia switch, which is supplied directly by the PCM (Powertrain Control Module), may be the cause of the issue. The PCM controls power to the fuel pump relay. If the inertia switch has no power, the relay will not receive power.

In some cases, the problem may be related to the wiring between the fuel pump and the relay. It is recommended to check for continuity and resistance in the wiring.

If the above solutions do not resolve the issue, it may be necessary to consult a professional mechanic or Ford technician for further diagnosis and repair. They may recommend checking the PCM pinout, voltage supply to the PCM and relay, or other potential issues.

It is important to note that attempting to repair or replace certain components may require specialized tools and skills, so it is always best to consult a qualified professional if you are unsure about any aspect of the diagnosis or repair process.

Fuel pump issues

Common Fuel Pump Issues in the 2002 F350

• No power to the fuel pump: This could be due to a faulty fuse, relay, wiring issue, or a problem with the inertia switch. Check Fuse #40, which controls power to the pump, and ensure it is intact. If the fuse is fine, check the wiring between the fuel pump and the relay for any signs of damage or corrosion.
• Inertia switch issues: The inertia switch is supplied power by the PCM (Powertrain Control Module). If the inertia switch has no power, check the wiring and connections to the PCM. You may need a voltmeter to test the voltage supply to the PCM and the relay.
• Fuel pump relay issues: The fuel pump relay is part of the central junction box (GEM module/fuse box) and is not serviceable separately. If the relay is faulty, the entire junction box may need to be replaced. This is a common issue in older model Fords.
• No start condition: If your F350 won't start even with a working fuel pump, there may be issues with the PCM or IDM (Injection Control Module). Ensure that the PCM is grounding the relay by testing pin 94, which should be a light blue wire with an orange tracer.
• Fuel bowl heater fuse: In some cases, a blown fuse #30 (fuel bowl heater fuse) can cause issues with the fuel pump and prevent the engine from starting. Unplugging the fuel bowl heater and replacing the fuse may resolve the issue.

Troubleshooting Steps:

• Check Fuse #40: Ensure that the fuse controlling power to the fuel pump is intact.
• Inspect Wiring: Check the wiring between the fuel pump and the relay for any signs of damage, corrosion, or loose connections.
• Test Inertia Switch: Ensure the inertia switch is receiving power from the PCM. If not, check the wiring and connections to the PCM.
• Fuel Pump Relay: If the issue persists, suspect a faulty fuel pump relay. As this is not serviceable separately, you may need to replace the entire central junction box/fuse box.
• PCM and IDM: If the fuel pump is working but the vehicle won't start, check the PCM and IDM for potential issues.
• Fuel Bowl Heater Fuse: If other components seem intact, check fuse #30 (fuel bowl heater fuse) and replace it if necessary.

Safety Precautions:

• Always refer to a qualified mechanic or automotive professional for complex repairs or diagnostics.
• Ensure the vehicle's battery connections are secure and the battery is in good condition.
• When working with electrical systems, always disconnect the negative battery terminal before proceeding.
• Use appropriate safety gear, including gloves and eye protection, when handling automotive repairs.

By following these steps and guidelines, you can effectively troubleshoot and resolve fuel pump issues in your 2002 F350, ensuring a reliable and efficient fuel system.

Fuel pump replacement

Step 1: Identify the Problem

Before replacing the fuel pump, it's important to diagnose the issue. Check if there is no power to the fuel pump or the inertia switch. Also, inspect the wiring between the fuel pump and the relay for any signs of damage or corrosion.

Step 2: Park the Vehicle and Locate the Fuel Pump

Park your vehicle on a level surface and engage the parking brake. The fuel pump is typically located inside the fuel tank, so you'll need to open the fuel cap and turn the key to the "ON" position to listen for the fuel pump's hum, which indicates it's functioning.

Step 3: Check the Fuel Pump Fuse and Relay

Locate the fuel pump fuse and relay. If the fuse is blown, replace it with one of the same amperage and recheck the fuel pump operation. If the fuse and relay are intact, proceed to the next step.

Step 4: Prepare for Fuel Pump Replacement

Relieve the fuel system pressure by disconnecting the negative battery cable. Siphon or drain as much fuel as possible from the tank. Disconnect the filler tube hose and the electrical connection to the pump.

Step 5: Remove the Fuel Tank

Support the fuel tank with a jack and a block of wood. Remove any retaining straps or bolts holding the tank to the frame, and carefully lower it.

Step 6: Disconnect the Fuel Pump

Disconnect the fuel lines and remove the fuel pump from the tank. Compare the old and new fuel pumps to ensure you have the correct replacement.

Step 7: Install the New Fuel Pump

Connect the fuel lines to the new pump. Lift the fuel tank and secure it with the retaining strap. Reconnect the filler tube hose and the electrical connector.

Step 8: Reassemble and Test

Reconnect the negative battery cable and fill the tank with fuel. Conduct a road test to confirm that the new fuel pump is functioning properly.

Safety Precautions:

• Work in a well-ventilated area away from open flames, sparks, or potential ignition sources.
• Wear safety glasses and gloves for protection.
• Keep a fire extinguisher nearby.
• Relieve fuel pressure before opening the fuel system.
• Use a support jack when handling the fuel tank.
• Clean the tank thoroughly during the repair process.
• Replace the fuel filter to ensure the smooth operation of the new fuel pump.

Note: The above steps provide a general guide for fuel pump replacement. For vehicle-specific instructions, refer to the owner's manual or seek advice from a qualified mechanic.

Fuel pump relay losing power

If your fuel pump relay is losing power, there could be a number of issues at play.

Firstly, it is important to locate the fuel pump relay. In most car types, the fuse box under the dashboard or the fuse box in the engine compartment houses the fuel pump relay. Consult your vehicle's owner's manual to identify the fuel pump relay's precise placement quickly.

Now, let's go over some common symptoms of a faulty fuel pump relay:

• An engine that stalls or cuts off is a typical sign of a faulty fuel pump relay. Your dashboard will likely display warnings, and the check engine light will be illuminated.
• A faulty fuel pump relay can reduce the fuel pump's power and, in turn, reduce the amount of fuel delivered to the engine, causing issues with acceleration.
• If the fuel pump relay has any faulty soldering, it may abruptly break the relay connection and stop powering the fuel pump. This will result in insufficient fuel or pressure in the combustion chamber, causing the engine to shut down.
• A malfunctioning fuel pump relay might leave the engine completely dead and unable to start due to a lack of fuel pressure.
• If you don't hear the fuel pump make a whirring sound when the ignition is turned on, this could indicate an issue with the fuel pump relay.

Now, let's discuss some potential fixes for a faulty fuel pump relay, specifically for a 2002 F350:

• Check the wiring between the fuel pump and the relay.
• Check for continuity/resistance in the wiring.
• Check the voltage supply to the PCM and the relay.
• Check for corrosion on the PCM boards.
• If the fuel pump relay is soldered into the central junction box, you may need to get a refurbished one or have a professional diagnose the issue.
• The fuel pump relay is powered by fuse #40 in the interior fuse box. Check if there is power on both sides of the fuse when cranking the engine. If not, the relay has likely failed and the fuse box will need to be replaced.

Frequently asked questions