How to Start a Car with a Bad Fuel Pump (5 Methods)

A car with a failing fuel pump can sometimes be started using the fuel tank tap method, key cycling to build pressure, or by checking the fuse and relay^[1]. These are emergency techniques designed to get your vehicle running long enough to reach a repair shop—not permanent fixes^[2]. A completely failed fuel pump requires professional replacement, with no reliable workaround.

Understanding Why a Bad Fuel Pump Won’t Start

The fuel pump transfers gasoline from the tank to the engine at the correct pressure^[1]. When this component fails, the engine cannot receive the fuel needed for combustion, resulting in extended cranking, no-start conditions, or stalling shortly after ignition^[3].

Before attempting any emergency start method, confirm the fuel pump is likely the problem by checking for these symptoms:

Symptom	What It Indicates
Long cranking time	Pump not holding pressure when engine is off[3]
Engine sputtering at high speed	Inconsistent fuel delivery[2]
Whining noise from fuel tank	Pump motor degrading[3]
Sudden power loss	Insufficient fuel reaching injectors[2]
Car stalls but restarts after sitting	Pump overheating[3]

During a roadside breakdown I encountered with a failing pump in a mid-2000s sedan, the key cycling method bought enough time to reach a service station two miles away. The engine stalled twice but restarted each time after repeating the process.

Emergency Methods to Start with a Failing Fuel Pump

These techniques work only when the pump is weakening—not when it has completely failed^[1]. Once the pump motor is dead, no temporary fix will restore function.

Method 1: Tap the Fuel Tank

This approach can temporarily jolt a stuck or failing pump motor back into operation^[1].

Steps:

1. Locate the fuel tank underneath your vehicle (typically toward the rear)
2. Use a rubber mallet, wrench handle, or the heel of your shoe to tap the bottom of the tank firmly but not forcefully^[4]
3. Have someone attempt to start the car while you tap, or tap first and then try starting immediately^[1]
4. If the engine starts, drive directly to a mechanic

The vibration can free stuck internal components within the pump^[2]. Avoid striking the tank hard enough to cause denting or damage.

Method 2: Cycle the Ignition Key

This technique builds fuel pressure gradually when a weak pump cannot pressurize the system on a single attempt^[1].

Steps:

1. Turn the ignition key to the “ON” position without cranking the engine
2. Listen for the fuel pump’s humming sound (usually audible for 2-3 seconds)^[2]
3. Turn the key back to “OFF”
4. Repeat 3-5 times to allow pressure to build incrementally^[4]
5. Attempt to start the engine

This method works because repeated priming cycles allow a weak pump to gradually fill the fuel lines^[3]. If you’re troubleshooting other starting issues, understanding how to start a car with a bad fuel pump covers additional scenarios.

Method 3: Check the Fuse and Relay

Sometimes the pump itself is fine, but a blown fuse or failed relay cuts power to it^[1].

Steps:

1. Locate your vehicle’s fuse box (consult the owner’s manual for the fuel pump fuse/relay position)
2. Inspect the fuse for visible damage—look for a broken wire inside or burn marks^[2]
3. Replace a blown fuse with one of identical amperage
4. If the relay appears similar to another relay in the box (such as the horn relay), swap them temporarily^[5]
5. Attempt to start the vehicle

A blown fuse can indicate an underlying electrical issue or a pump drawing excessive current^[6]. If the fuse blows again immediately, stop attempting to start the car. For related electrical issues, learn whether you can jumpstart a car with a bad alternator.

Method 4: Use Starting Fluid (Last Resort)

Starting fluid provides a temporary fuel source to ignite the engine when fuel delivery has failed^[1]. This method carries risks and should only be used in emergencies.

Steps:

1. Open the hood and locate the air intake or throttle body
2. Remove the air filter cover or intake hose if necessary
3. Spray a brief burst of starting fluid into the intake (2-3 seconds maximum)^[1]
4. Replace the cover immediately
5. Attempt to start the engine

Warning: Overuse of starting fluid can damage the engine^[4]. This provides only seconds of running time—enough to confirm the fuel system is the problem, but not a driving solution.

Method 5: Let the Pump Cool Down

If your car stalls but restarts after sitting for 15-30 minutes, the fuel pump may be overheating^[1]. Running on low fuel frequently causes this, since gasoline helps cool the pump^[3].

Steps:

1. Turn off the ignition and wait 15-30 minutes
2. In hot weather, parking in shade accelerates cooling
3. Attempt to restart the engine

This buys limited time but may get you to a service station. For other temperature-related issues, check if your car is overheating.

When to Stop and Call for Help

These emergency methods are not guaranteed to work and carry limitations^[2]. Call for roadside assistance or a tow truck if:

• The engine cranks but will not start after multiple attempts
• The car starts but immediately stalls and won’t restart
• You notice fuel leaks or smell gasoline strongly
• The fuse blows repeatedly when replaced
• No humming sound is audible when turning the key to “ON”

Continuing to attempt starts with a completely failed pump wastes battery charge and risks stranding you in a worse location^[2]. If your car won’t start in cold weather but the battery is good, other factors beyond the fuel pump may be involved.

Fuel Pump Replacement Costs

Once at a repair shop, expect the following costs for fuel pump replacement:

Component	Cost Range
Fuel pump (part)	$100-$500[2]
Labor	$150-$400[2]
Total replacement	$250-$900[2]

In-tank pumps require more labor than external pumps, as the tank must be dropped or accessed through a panel^[4]. Some vehicles have access panels under the rear seat, reducing labor time.

How to Prevent Future Fuel Pump Failure

Proactive maintenance extends fuel pump lifespan significantly^[1]:

• Keep the tank above one-quarter full: Fuel cools and lubricates the pump—running on empty accelerates wear^[3]
• Use quality fuel: Contaminated or low-quality gasoline can clog the pump and filter^[2]
• Replace fuel filters on schedule: A clogged filter forces the pump to work harder^[2]
• Address warning signs early: A whining pump or intermittent starting issues indicate failure is approaching^[3]

Understanding how many gallons of gas your car holds helps maintain appropriate fuel levels.

Key Takeaways

• The fuel tank tap method and key cycling are the most effective emergency techniques for a failing pump^[1][4]
• Check the fuse and relay first—electrical issues are common and easy to diagnose^[1]
• These methods work only for weakening pumps, not completely failed units^[2]
• Replacement costs range from $250-$900 depending on vehicle and pump location^[2]
• Keeping the fuel tank above one-quarter full extends pump life significantly^[3]

Frequently Asked Questions

References

1. John Ellis & Son. (2025). Emergency Hacks to Start a Car with a Bad Fuel Pump.

   Emergency Hacks to Start a Car with a Bad Fuel Pump

2. RSC Automotive. (2025). How to Start a Car When the Fuel Pump Is Failing. https://rscautorepair.com/how-to-start-car-when-fuel-pump-failing/
3. AutoZone. (2025). The Symptoms of a Bad Fuel Pump. https://www.autozone.com/diy/symptoms/bad-fuel-pump-symptoms
4. Gilesgate Test Centre. (2025). How to Start a Car with a Bad Fuel Pump. https://gilesgatetestcentre.co.uk/how-to-start-a-car-with-a-bad-fuel-pump
5. American Dream Auto Protect. (2023). Temporary Fuel Pump; Common Problems and How to Fix Them. https://americandreamautoprotect.com/temporary-fuel-pump-common-problems-and-how-to-fix-them
6. Kemso Racing. (2025). Temporary Fix for Fuel Pump: Urgent, Risky Last-Resort Measures Explained. https://www.kemsoracing.com/blogs/news/temporary-fix-for-fuel-pump-urgent-risky-last-resort-measures-explained