Shocking Signs Your Fuel Pump Relay Is Failing: How To Tell If Fuel Pump Relay Is Working

Essential Information

When you turn the ignition key, the relay receives a signal from the computer and closes the circuit, allowing power to reach the fuel pump.
You might hear a clicking sound coming from the fuel pump relay when you turn the key, indicating that the relay is trying to engage but failing.
Locate the fuel pump relay by referring to the fuse box diagram or using a multimeter to test each relay until you find the one that corresponds to the fuel pump.

Your car won’t start, and you’re left scratching your head, wondering what’s wrong. It could be a multitude of issues, but one common culprit is a faulty fuel pump relay. This small but crucial component plays a vital role in delivering fuel to your engine, and a malfunction can leave you stranded. So, how do you know if your fuel pump relay is the problem? This guide will walk you through the process of diagnosing a faulty fuel pump relay and help you determine if it’s the root cause of your car’s starting troubles.

Understanding the Fuel Pump Relay

The fuel pump relay acts as a switch, controlled by the car’s computer, that allows electricity to flow to the fuel pump. When you turn the ignition key, the relay receives a signal from the computer and closes the circuit, allowing power to reach the fuel pump. The fuel pump then begins to draw fuel from the tank and send it to the engine.

Signs of a Faulty Fuel Pump Relay

Several signs can indicate that your fuel pump relay is malfunctioning. These include:

No Start Condition: The most obvious sign is that your car won’t start at all. When you turn the key, you might hear the starter engage, but the engine won’t fire up.
Clicking Sound: You might hear a clicking sound coming from the fuel pump relay when you turn the key, indicating that the relay is trying to engage but failing.
Intermittent Starting Issues: Your car might start sometimes but not others, suggesting a problem with the relay’s ability to consistently deliver power.
Fuel Pump Doesn’t Run: If you can hear the fuel pump running when you turn the key, it’s likely not the relay. However, if you don’t hear the pump running at all, the relay could be the culprit.

How to Test the Fuel Pump Relay

Testing the fuel pump relay can be done with a multimeter or by using a simple continuity test. Here’s a step-by-step guide on how to test the relay:

1. Locate the Fuel Pump Relay: The fuel pump relay is typically found in the fuse box under the hood or inside the passenger compartment. Consult your car’s owner’s manual for the specific location.
2. Disconnect the Battery: For safety, disconnect the negative terminal of your car battery before proceeding.
3. Identify the Relay: Locate the fuel pump relay by referring to the fuse box diagram or using a multimeter to test each relay until you find the one that corresponds to the fuel pump.
4. Remove the Relay: Carefully remove the fuel pump relay from the fuse box.
5. Continuity Test: Use a multimeter set to the continuity setting. Touch the probes to the two metal terminals on the relay that are labeled “85” and “86.” You should hear a beep indicating continuity. Then, touch the probes to the terminals labeled “30” and “87.” You should also hear a beep. If you don’t hear a beep, the relay is faulty.
6. Voltage Test: You can also test the relay for voltage. Set the multimeter to the DC voltage setting. Touch one probe to the “30” terminal and the other probe to the “87” terminal. With the ignition key turned on, you should read a voltage reading. If there is no voltage, the relay is not receiving power from the computer and needs replacement.
7. Replace the Relay: If the relay fails either the continuity or voltage test, you’ll need to replace it. Purchase a new relay from your local auto parts store, making sure to get the correct type for your vehicle.

Other Potential Causes of No Start

While a faulty fuel pump relay is a common cause of starting problems, it’s important to remember that other issues can also lead to a no-start condition. These include:

Dead Battery: A dead battery can prevent your car from starting.
Faulty Starter Motor: A faulty starter motor won’t be able to turn the engine over.
Fuel Pump Failure: The fuel pump itself might have failed, preventing fuel from reaching the engine.
Fuel Filter Clogging: A clogged fuel filter can restrict fuel flow.
Spark Plug Problems: Faulty spark plugs can prevent the engine from igniting the fuel.

Checking Other Components

If you’ve tested the fuel pump relay and it’s working correctly, you’ll need to investigate other possible causes of your car’s starting problems. Here’s how to check some of the other components:

Battery: Check the battery voltage with a multimeter. If it’s below 12.6 volts, your battery might be dead or weak.
Starter Motor: Listen for a clicking sound when you turn the key. If you hear a clicking sound but the engine doesn’t turn over, the starter motor might be faulty.
Fuel Pump: Listen for the fuel pump running when you turn the key. If you don’t hear it, the fuel pump might be faulty.
Fuel Filter: Inspect the fuel filter for any signs of clogging.
Spark Plugs: Check the spark plugs for wear and tear.

A Final Word on Troubleshooting

Troubleshooting a no-start condition can be challenging, but with a systematic approach and the right tools, you can often identify the problem. Remember to consult your car’s owner’s manual for specific instructions and diagrams. If you’re not comfortable working on your car, it’s best to consult a qualified mechanic.

Shocking Signs Your Fuel Pump Relay is Failing: How to Tell if Fuel Pump Relay is Working