5 Reasons Your Car Won’t Start After Getting Gas?

It’s frustrating when your car won’t start after a fill-up. Suddenly you’re stuck with a car that refuses to turn over.

In this quick guide, we’ll walk through the most common reasons a car won’t start after getting gas and the basic troubleshooting steps to get you back on the road.

With some knowledge of potential issues, you can identify the problem and solve this annoying situation yourself.

After spending tons of hours and reading suggestions by experienced people on relevant forums, I found that if your car sputters or takes multiple tries to start after getting gas then the problem most likely lies within the fuel system of the car, such as fuel injectors, fuel pump and fuel pressure regulator.

Are you experiencing sputtering in your car after refueling? Learn more by reading our guide on car sputtering after getting gas.

If you prefer a brief overview instead of reading the entire article, here is a summary table to quickly gather the information:

Causes of Car Won’t Start After Getting Gas	Descriptions
EVAP Purge Valve Stuck Open	Allows too much fuel vapor into engine, causing overly rich air/fuel mixture so car won’t start.
Clogged Fuel Filter	Restricts fuel flow to engine, starving engine of fuel needed to run.
Faulty or Clogged Charcoal Canister	Unable to absorb fuel vapors, so vapors flood engine causing rich mixture.
Faulty Fuel Pump	Fails to pump enough fuel into engine for proper combustion.

Note: If you don’t want to understand how the EVAP system works and want to know about the causes of car not starting after filling gas, you can jump straight to the section.

My Personal Experience With Car Not Starting After Getting Gas

My brother drives an older Nissan Altima that would stall out after filling up with gas. He asked me to take a look since I’m handy with cars. I started by testing fuel pressure and found it was very low.

After checking the fuse and relay, I suspected the fuel pump was failing. We dropped the gas tank and I tested power to the pump, which was good. But the pump made no noise when powered on.

Replacing the worn-out fuel pump for about $100 solved the stalling issue and now my brother’s Altima starts right up after gassing up.

How EVAP System Works?

Before diving into the causes of the car not starting after refilling the gas, it is quite important to understand how the EVAP system works. It will help you troubleshoot your problem.

EVAP system of an engine works by sucking extra fuel vapors from the canister through the purge valve to prevent leakage of fuel in the environment. 

There are the following main components of EVAP system:

• Charcoal Canister
• Purge Valve
• Canister Vent Valve
• Fuel Tank Pressure Sensor

The schematic diagram of an EVAP system is shown in the figure below:

Before continuing, the PCM (powertrain control module) and engine control unit (ECU) are the same terms used interchangeably. 

The canister is a small container filled with activated charcoal to trap the fumes of the fuel with the help of activated charcoal.

There is a pressure sensor on the fuel tank that detects any considerable leakage from the fuel tank. The fuel tank pressure sensor sends the data to the engine control unit module.

The purge valve is a one-way solenoid valve that connects the charcoal canister to the engine’s intake system. When the car engine is off, the purge valve is closed. Once the engine is up and running, the ECU continuously and moderately opens the purge valve.

The purge valve is opened by the engine control unit to create a vacuum that pulls fresh air through the vapor canister. The fresh air forces the fuel vapors and delivers them to the engine so that they can be burnt in the normal combustion process.

The vent valve is a one-way solenoid valve that is connected to the canister. The vent solenoid valve is usually open so that air is drawn through the canister where it is mixed with the vapor and then drawn into the engine and burnt.

When there is a large leak detected in the EVAP system, the engine control unit of the car will close the vent valve to seal the system during the self-diagnostics of a large leak.

Causes of Car Won’t Start After Getting Gas

Here are the causes of the car having trouble starting after getting gas.

1. EVAP Purge Valve is Stuck Open

It is a common problem with the fuel delivery system of vehicles, especially after filling them up with gas. The EVAP purge valve is responsible for removing the vapors from the canister and purging them into the engine. It helps in preventing the buildup of fuel gases in the fuel tank.

In some cases, the EVAP valve can become stuck open when allowing excessive vapors to enter the engine. When refueling the car, a lot of fumes build up in the fuel tank.

A proportion of the fuel vapors, that should be contained in the vehicle’s charcoal canister, are pushed past the open EVAP valve and into the intake manifold. When the car is restarted, the air-fuel mixture is too rich to support combustion.

When there is excessive fuel in the air-fuel mixture, fuel will not be completely burnt, due to which the car takes several tries to start after it is refilled with the fuel.

In such cases, you have to step on the gas pedal more to open the throttling valve of the air intake manifold and bring more air into the engine for combustion.

If holding down the pedal halfway trick works to start the car, this is the biggest sign that you may need to replace the purge valve.

To diagnose a faulty purge solenoid valve, you can do the following steps:

• Locate the purge valve by taking help from the owner’s manual.
• Bypass the purge valve by temporarily disconnecting it from the intake manifold. Now, start the car. If the car readily starts, it means that the purge valve is faulty.
• Next, remove the purge valve from the car. You either need a spanner/screwdriver to remove the purge valve or you can simply remove it by rotating it anticlockwise with your hands. 
• After removing the purge valve, if you can blow through it in either direction it means that the purge valve is confirmed faulty.
• Another bulletproof test you can do to diagnose the purge valve is to pull the vacuum on the side of the purge valve that goes to the intake manifold through the vacuum pump. This is the same side of a purge valve through which the intake manifold of the engine creates the vacuum to suck fuel vapors from the canister. If the purge valve is not holding a vacuum, it means that the purge valve is faulty.

Check out the below video for a diagnostic test of a purge valve.

2. Clogged Fuel Filter Prevents Fresh Gasoline From Reaching Engine During Ignition

If you notice that your car isn’t starting after refilling with fuel, you might want to check the fuel filter. Fuel filters remove dirt, water, and other impurities from the fuel before it enters the engine.

When the fuel filter gets clogged, it does not allow the fuel to pass through. This can cause poor engine performance and ultimately affect the car’s ability to start.

A clogged fuel filter can cause low engine power and poor fuel flow. Moreover, a clogged filter may increase the chance of the engine running rough.

How to test?

Before attempting this test, be sure to drain all gasoline from the fuel filter to avoid any potential hazards.

For the test, you’ll need a straw (to avoid ingesting gasoline) and the fuel filter itself.

1. Slide the straw over the inline connection, carefully ensuring a tight connection that won’t obstruct airflow.
2. Blow into the straw and observe if the air flows through the filter effortlessly or encounters obstruction.

If air flows through the filter without any hindrance, the fuel filter is in good condition. However, if the airflow is slow or blocked, it indicates a faulty fuel filter that needs to be replaced.

3. Faulty or Clogged Charcoal Canister Unable To Trap Fuel Vapors

The charcoal canister is responsible for capturing the fuel vapors. If the bed of activated charcoal in the canister is clogged with dirt, the fuel vapors from the fuel tank will not go to the canister.

Instead, all the fuel vapors will flow back to the fuel tank, which will make it difficult to refill the fuel tank.

So, if the charcoal canister is unable to hold the fuel vapors, the excessive amount of fuel vapors will pass through the purge valve, due to which the car will take several tries to start after getting gas. 

Here is how to diagnose a faulty charcoal canister:

• Locate the charcoal canister in your vehicle’s engine. It is normally connected to the purge valve from the bottom.
• Visually inspect for cracks or damage.
• Now remove the charcoal canister from the engine.
• Connect the hose to the port of the charcoal canister which is connected to the fuel tank.
• Blow the air through the hose.
• If the blown air does not come out of the other ports on the charcoal canister, it means that the charcoal canister is faulty.

Check out the below video to understand how to remove the charcoal canister.

4. Faulty Fuel Pump Preventing Pressurized Fuel Delivery

The fuel pump serves the crucial function of transferring fuel from the vehicle’s tank to the engine, where it is utilized to generate the necessary power for the car’s movement.

When the fuel pump malfunctions, it disrupts the supply of fuel to the engine, preventing the vehicle from receiving the required fuel to create power and perform optimally.

One of the reasons why a faulty fuel pump can lead to a stuttering car right after refueling is due to the phenomenon known as “vacuum in the air space“.

If the fuel tank is incapable of adequately venting, it creates a vacuum in the space above the fuel.

Consequently, this vacuum negatively impacts the fuel pump, impairing its ability to receive a sufficient fuel supply, thus resulting in a sputtering car.

In addition, when you refill the gas tank, any debris already inside the tank such as dirt or small particles will become mixed into the new fuel.

Fuel pumps do not last forever. That’s why vehicle manufacturers recommend replacing a fuel pump after every 60,000 to 100,000 miles. 

To learn more you can read my guide on common problems after changing fuel pump.

Here are the symptoms of a faulty fuel pump in a vehicle’s engine:

• Sputtering noise of car when speed is high
• Whining noise from the fuel tank
• Engine is starved for fuel when accelerating
• Reduced gas mileage
• The whining noise of a fuel pump can be heard when you turn on ignition key without starting the engine

Also Read: Car losing power when turning corners

Here is how to diagnose a fuel pump:

• Turn the ignition on
• Open the gas cap of the fuel tank
• If you do not hear the sound from the fuel tank, it could mean the fuel pump is not running
• Now, turn the ignition off
• Locate the fuse box and find the fuse for the fuel pump with the help of the fuse box layout diagram of your vehicle
• If the fuse of the fuel pump is fine, check the relay of the fuel pump in the fuse box
• If the relay clicks, it means that it is fine
• Now, turn on the ignition
• Next, check the pressure of fuel using the fuel pump pressure test kit. You can read my guide on bad fuel pressure regulator symptoms to learn more
• Locate the test port on the fuel line
• Fit down the hose of a pressure test kit on the test port
• If there is no fuel pressure on the test gauge, it means that the fuel pump needs to be replaced

Check out the below video to understand how to diagnose the fuel pump.

Here is how to check fuel system pressure:

5. Fouled Spark Plugs Unable to Combust Fuel

Spark plugs are a critical engine component that can fail for a variety of reasons. When functioning properly, the spark plug provides the spark that ignites the air-fuel mixture in the engine’s cylinders.

However, over time spark plugs can become contaminated or damaged, preventing them from sparking properly. This is known as spark plug fouling, and it can cause major engine issues.

Some common causes of spark plug fouling include:

• Oil deposits: Oil leaking past worn piston rings or valve seals can coat the spark plugs, insulating them from firing properly. This oil fouling prevents the spark from jumping the gap.
• Fuel deposits: Unburned fuel, carbon, and additives can leave deposits on the spark plug tip. These deposits interfere with the spark, especially if the engine often runs rich or idles for long periods. Fuel-fouled plugs appear dry and black.
• Coolant deposits: Coolant leaking from a failed head gasket or cracked engine block can contaminate the spark plug wells. The minerals and chemicals in the coolant can leave a white, chalky deposit on the plugs.
• Corrosion: Environmental contamination, improper anti-corrosion additives, or weak ignition voltage can all cause the spark plug electrodes to corrode. This corrosion increases the gap required for sparking.
• Ash deposits: Oil and fuel additives containing phosphorus or zinc can leave ash deposits that insulate the spark plug.

How does it affect car starting?

Spark plug fouling is a common reason that vehicles fail to start after refueling. One common scenario is when you fill your gas tank to the brim, excessive fuel can leak through the fuel injectors.

The leaky fuel injectors may drip gasoline into the cylinders even when the engine is off. This leaves puddles of fuel that foul the spark plugs. When the ignition is engaged, the plugs fail to fire because they are smothered with gasoline. This causes a no-start condition.

How to fix?

The first solution is to clean spark plugs properly. First, blow away dirt and junk using compressed air. After that, soak the spark plug in brake cleaner until all the gunk is gone. You can also use a soft brush to get rid of any remaining debris.

Next, you should check fuel pressure regulator. It has a diaphragm that gets ruptured, due to which fuel pressure regulator is unable to maintain fuel pressure. It will cause excessive fuel to flow through the fuel pressure regulator which will foul the spark plugs.

In my guide on how fuel pressure regulator can fail, I have explained everything about this. So, you can check it out there.

Lastly, check fuel injectors. They have O-rings to prevent fuel leakage directly into the engine cylinders. If the O-rings are broken, fuel will drip into the combustion chamber and foul the spark plugs.

Why Doesn’t the Car Start After Filling Up Gas?

The most common reason a car won’t start or sputters after getting gas is stuck open purge control solenoid valve of the evaporative emission control system (EVAP) which sucks all fuel vapors from the charcoal canister to the engine.

Since extra fuel vapors are forced from the canister to burn in the engine cylinder after refilling a car with fuel, the air-to-fuel mixture becomes too rich with the fuel to support the combustion. As a result, the car won’t start after getting gas.

Car Won’t Start After Getting Gas: Final Thoughts

To recap why the car is sputtering or not starting after getting gas, here are the following causes:

• EVAP Purge Valve is Stuck Open
• Clogged Fuel Filter
• Faulty or Clogged Charcoal Canister
• Faulty Fuel Pump

Some First Hand Experiences Shared By Users In Different Communities

Our team conducted research across various online communities, forums, and subreddits to gather user comments and opinions on “car not starting after getting gas”.

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