How to Repair a Faulty Fuel Injector Relay in 2016-2020 Ford F-150 | The Motor Guy (2024)

To repair a faulty fuel injector relay in your 2016-2020 Ford F-150, start by disconnecting the negative battery terminal and locating the relay in the engine compartment fuse box.

Inspect the relay for physical damage, check the wiring harness for frayed wires or loose connections, and test the relay’s continuity with a multimeter.

If the relay is faulty, replace it with a new one, ensuring correct installation and alignment. Next, perform diagnostic tests to identify the root cause of the issue, and address any injector circuit problems.

As you proceed with these steps, you’ll uncover more detailed guidance to get your F-150 running smoothly again.

Safety Precautions and Preparation

Before diving into the repair process, take a few essential steps to affirm your safety and the success of the job by disconnecting the negative battery terminal, gearing up with protective gear, and preparing a well-ventilated workspace.

This will prevent electrical shock, short circuits, and inhalation of harmful fuel vapors.

Wear safety goggles and gloves to protect yourself from fuel spills and sharp components during the repair process.

Confirm you have a fire extinguisher nearby to mitigate any fire hazards that could arise from fuel leaks or sparks.

In your work area, make certain there’s adequate ventilation to avoid inhaling fuel vapors.

Review the vehicle’s service manual for specific procedures and safety guidelines related to the fuel injector relay on your 2016-2020 Ford F-150.

Having the right safety equipment and a well-prepared work area will give you peace of mind and confidence to tackle the repair job.

By taking these precautions, you’ll be able to focus on the task at hand and get the job done efficiently and safely.

Locating the Fuel Injector Relay

You’ll find the fuel injector relay in the engine compartment fuse box, typically situated near the battery on the driver’s side of your 2016-2020 Ford F-150.

This is the fuel relay location you need to access for repair or replacement.

To identify the specific relay for the fuel injectors, refer to the diagram on the fuse box cover that labels each relay and fuse by function.

The fuel injector relay is often a black rectangular component, and its position can vary slightly based on the engine configuration (e.g., V6 or V8).

Once you’ve located the relay, you’ll notice it’s easily accessible by removing the fuse box cover and pulling the relay directly out of its socket for testing or replacement.

Take a closer look at the relay’s appearance and position to guarantee you’re working with the correct component. With the relay located, you’re one step closer to diagnosing and fixing the issue with your fuel injector relay.

Inspecting the Relay for Damage

With the fuel injector relay identified and accessed, inspect it closely for any signs of physical damage, such as cracks or corrosion on the housing and terminals, which can indicate a failure point.

This visual inspection is a vital step in relay maintenance tips, as it can help you identify common relay issues before they escalate into more severe problems.

Check for burnt or melted connections on the relay, as high resistance or overheating can compromise its functionality and lead to injector issues.

Next, examine the relay socket and wiring harness for frayed wires or loose connections, as poor electrical contact can prevent the relay from operating correctly.

If possible, compare the suspect relay with a known good relay to verify proper operation and rule out failure due to component defects.

Testing Relay Continuity With Multimeter

Set your multimeter to the resistance (ohm) setting to measure the relay contacts and determine if the fuel injector relay is functioning correctly.

This test will help you identify a relay malfunction and diagnose the issue.

Disconnect the relay from the vehicle’s electrical connector and place the multimeter probes on the relay terminals to check for continuity.

A reading of 0 ohms indicates a good relay, while an open circuit (infinite resistance) signals a faulty relay.

Furthermore, check for continuity between the relay’s coil terminals to verify that the coil is functioning. A reading between 60 to 120 ohms is typically expected in most relays.

Remember to always refer to the vehicle’s service manual for specific resistance specifications and testing procedures relevant to the 2016-2020 Ford F-150.

Replacing the Faulty Relay

Now that you’ve confirmed the fuel injector relay is faulty, it’s time to replace it with a new one to get your Ford F-150’s fuel system running smoothly again.

Before you start, make certain you’ve got the correct relay type, as different models may have varying relay configurations.

Common symptoms of a faulty relay include engine misfires, poor engine performance, and decreased fuel efficiency.

To replace the relay, locate it in the power distribution box under the hood, which should be labeled for easy identification.

Verify the ignition is off and disconnect the negative battery cable to prevent any electrical shorts or shocks during the process.

Gently pull the faulty relay straight out of the socket, taking care not to damage the surrounding components or wiring.

Install the new relay by aligning it correctly with the socket and pushing it down firmly until it clicks into place, confirming a secure connection.

After replacement, reconnect the negative battery cable and start the vehicle to confirm that the fuel system is functioning properly and the relay is operational.

Injector Circuit Diagnosis Steps

You’ll need to perform a series of diagnostic tests to identify the root cause of the fuel injector circuit problem.

Start by checking for fault codes stored in the ECU, specifically looking for issues related to the injector circuit. This will give you a starting point for your diagnosis.

Next, measure the resistance of the injector to verify it falls within the specified range of 11.4 to 13.4 ohms, which confirms the injector’s functionality.

There are different injector types, but for your 2016-2020 Ford F-150, this range applies.

Utilize an oscilloscope to check the injector signal, which helps identify any irregularities in the injector’s operation. This is essential for proper fuel delivery.

Inspect the wiring harness for continuity and resistance, comparing your readings to a known good injector to identify potential wiring faults.

If the resistance of the number 2 injector is found to be out of spec, proceed with replacement and re-test the circuit to confirm proper functionality.

Identifying and Confirming the Fault

After completing the injector circuit diagnosis, turn your attention to the fuel injector relay itself to identify and confirm the fault by scanning the vehicle’s ECU for any fault codes related to the relay.

This step can provide valuable insight into potential issues, helping you pinpoint the problem.

Next, test the relay’s resistance with a multimeter to verify it falls within the manufacturer’s specified range, typically around 70 to 90 ohms for standard relays.

This will help you determine if the relay is functioning correctly.

Inspect the wiring connected to the fuel injector relay for any visible damage, corrosion, or loose connections that could disrupt the circuit.

Also, use a test light or multimeter to check for battery voltage at the relay terminals when the ignition is turned on to confirm that the relay is receiving power.

If the relay fails the resistance test or doesn’t receive power, it’s likely faulty and should be replaced to restore proper fuel injector operation.

Installing the New Injector Correctly

With the faulty relay replaced, turn your attention to installing the new fuel injector, making certain it’s properly seated and connected to prevent future issues.

Before installation, verify the new injector’s resistance falls within the specified range of 11.4 to 13.4 ohms to confirm its functionality.

Clean the injector ports and surrounding areas to prevent debris from contaminating the fuel system during installation.

Compare the new injector with the old one to make certain correct visibility and pin positions, preventing misalignment.

Apply a light coat of engine oil to the O-rings of the new injector to facilitate proper sealing and ease of installation, making certain correct injector alignment.

This O-ring lubrication will help the injector seat properly, reducing the risk of leaks or other issues.

Once installed, reconnect the injector harness and prepare for further testing to make certain the repair is successful.

Verifying Proper Fuel Injector Operation

Now that the new fuel injector is installed, it’s time to verify its proper operation to confirm the repair is successful.

You’ll want to check for any fault codes stored in the ECU that may indicate injector circuit issues, such as a specific cylinder malfunction.

Next, measure the resistance of the fuel injector using a multimeter; it should fall within the specified range of 11.4 to 13.4 ohms to validate functionality.

Furthermore, test the injector’s signal and continuity to guarantee there are no breaks or shorts in the wiring leading to the injector.

If you have access to an oscilloscope, use it to analyze the injector’s waveform during operation, looking for consistent and correct patterns that indicate proper functionality.

Avoid performing injector cleaning or performance tuning at this stage, as these processes may mask any underlying issues.

Instead, focus on verifying the injector’s operation and addressing any problems that arise.

Final Checks and Road Testing

You should perform a series of final checks and road tests to verify the fuel injector relay repair is successful and the vehicle is operating smoothly.

Begin by conducting a continuity test to verify proper electrical connections within the relay circuit.

Next, use a diagnostic scanner to check for any stored fault codes in the Engine Control Unit (ECU), confirming that no new issues have emerged after the repair.

A visual inspection of the fuel injector wiring harness is also necessary to identify any signs of wear or damage that could affect performance.

Start the vehicle and allow it to idle for several minutes, monitoring for any irregularities in engine performance or fluctuations in idle speed.

Employ troubleshooting techniques to identify any potential issues.

Finally, take the vehicle for an extended road test under various driving conditions, using performance monitoring to verify smooth operation and confirm that the repair has resolved any previous issues.

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