Gas Tank Won’t Fill – Possible Reasons and Viable Fixes

Gas tank won t fill because your car’s evaporative emission control system (EVAP) is faulty or clogged. Going to a gas station to fill up your tank whenever you run out of gas is the natural thing to do, and your gas gauge’s “full” line should appear when the gas is ready.

However, occasionally the pump would cut off before the tank is full. This article explains why your gas tanks won’t fill and how you can fix the issue.

What Is the Possible Reason Your Gas Tank Won’t Fill?

The possible reason your gas tank won’t fill is because something is wrong with your evaporative emissions control system. The EVAP could either be faulty or clogged. Its purpose is to transport fuel vapors from the tank to the intake manifold for combustion while collecting and storing them there.

Defective EVAP

Numerous valves and sensors are crucial components of the maze-like EVAP system. Among these, the purge valve, vent valve, and charcoal canister are the most frequently mentioned causes of EVAP problems. Any malfunction or obstruction in these parts might throw off the system’s delicate balance, allowing fuel vapors to escape adequate capture and containment.

A flawed EVAP system may also result from physical harm. These include cracks or leaks brought on by extended exposure to the outdoors or potential road hazards. No matter how slight, these flaws can compromise the system’s ability to safely confine fuel vapors and send them to the engine for combustion.

In rare cases, the problem may be linked to a faulty gasoline Tank Pressure Sensor. This sensor is a vital component that helps keep track of the pressure inside the gasoline tank. Inaccurate readings from this sensor could cause the EVAP system to malfunction. This may result in insufficient fuel vapor containment and fuel-filling issues.

Low Engine Performance

Misfires, weak sparks, or an inappropriate air-fuel combination are just a few of the problems that can lead to poor engine performance. Unburned fuel vapors can be produced more frequently in engines when the fuel is not burned effectively during combustion. These extra vapors can overload the EVAP system.

As a result, they prevent it from effectively trapping and storing the gasoline vapors, which can cause fueling issues.

Clogged Vent or Breather System

While you are filling the petrol tank, air must be able to leave, and this is made possible by the vent or breather system. In the vent or breather system, debris, dust or even spider webs can build up over time. During refueling, these obstructions limit the amount of air that can enter and exit the tank. The pressure inside the tank can increase in the absence of adequate ventilation.

Even though the tank might not be full, the gasoline pump nozzle may shut off early. As a result, you are unable to entirely fill your gas tank due to this early shut-off. When you remove the gas cap, you might also hear a “whoosh” sound, which denotes the release of pressure. The gas may need to be pumped extremely slowly or the nozzle held at a specific angle for adequate filling.

Blocked EVAP

One of the common reasons why your gas tank won’t fill is because of a blocked EVAP system. This essential part of modern cars prevents dangerous fuel vapors from leaking into the air. However, it is susceptible to clogging due to poor vehicle maintenance. As the car ages and experiences wear and tear, numerous particles, pollutants, and dirt enter the EVAP system.

It eventually ends up accumulating in its compartments and hoses. As a result, this buildup prevents the fuel vapors from flowing through the system freely. This causes a clog that makes it difficult for the EVAP system to trap further gasoline vapors from the fuel vessel effectively. The once-smooth refilling procedure becomes tiresome when the fuel vapors linger inside the fuel tank.

It is challenging to obtain a full fill-up since the gasoline pump frequently shuts off prematurely. This may be due to the failure of the EVAP system to release trapped air during refueling efficiently. Because of this, you are left in the dark about the actual fuel capacity in their tanks due to inaccurate fuel level readings. You may run out of fuel unexpectedly, putting you in an uncomfortable and potentially dangerous driving scenario.

Faulty EVAP Canister

The check engine signal on your car’s dashboard may come on due to a faulty EVAP canister. The fuel vapors are held in the EVAP can until the engine is activated. At this point, they are transferred for final combustion. There are various indicators that an evaporative emission control canister is malfunctioning.

In the gasoline tank, the high pressure it creates prevents air from passing while the fuel is being added. The fuel pump switches off as a result before the tank is full. Due to damage or a break in the EVAP can, the automobile may also smell like gasoline.

What Are the Possible Solutions for Your Gas Tank Not Filling?

The possible solutions for your gas tank not filling are to check the gas cap, then clean the EVAP system, change the defective EVAP components and check with a diagnostic tool. It is advisable to act immediately when you notice before the problems aggravate.

Use a Scan Tool To Run Diagnostics

The first step to solving any issue is to find the root of the issue. You can diagnose your car with a scan tool to determine why the petrol tank isn’t full. You can access the recorded codes on your car’s computer using a handheld scan tool. The OBD-II port under the dash is where the scanner must be connected.

After connecting the scanner, start the engine and leave the scanner to work. It will read the codes and inform you of the issues with your vehicle.

Inspect the Gas Cap

Inspecting the gas cap should be your first step if your vent hose gas tank isn’t full. Ensure the gas cap is securely fastened for damage, such as cracks or leaks. You must replace the cap if it is damaged.

Fortunately, gas caps are widely available and reasonably priced. One should be available at your neighborhood car parts shop.

EVAP System Maintenance

Cleaning the EVAP system comes next once the cap is in good condition. Any dirt or debris that might be keeping the system from functioning properly will be eliminated by doing this. With the use of a wire brush and a can of air that is compressed, you can easily clean the EVAP system.

Clean up any debris or dirt in the hoses and parts by using compressed air to blow it out. Next, scrub away any last bits of dirt with the wire brush. You can take your vehicle to an auto mechanic if you need more confidence to clean the EVAP system. They ought to be able to clean the system and restore the correct operation for you.

Change the Defective EVAP Components

A different choice is to swap out any malfunctioning EVAP system parts. The purge valve, vent valve, or charcoal canister may be examples. If you need clarification on what part is malfunctioning, you can bring your car to a qualified mechanic who can identify the problem. They can replace the problematic component for you once they have determined the issue.

FAQs

Why Is Your Gauge Reading Empty When the Tank Is Full?

Your gauge is reading empty even when the tank is full because there is an issue with your gauge. There are three common issues with gauges; the first is when the gauge is stuck on full. You last refueled a week ago and have been driving frequently.

Even if you know this, the gas gauge still indicates that you have a full tank. No, your fuel efficiency has not magically improved overnight; instead, it is more probable that you are experiencing a problem with your variable resistor.

It might be defective wiring, a problem with the resistor’s open circuit, or, in rare cases, merely a bad gauge. Whatever it is, it’s not a DIY remedy, so calling in our technicians is worthwhile.

Why Does the Gas Pump Keep Stalling When the Tank Isn’t Full?

The gas pump keeps stalling when the tank isn’t completely full because there is an issue with your car’s fuel tank venting system or Evaporative Control System (EVAP). In order for the fuel to enter your vehicle’s fuel tank smoothly, the air inside the tank must be removed.

Incorrectly operating EVAP or venting systems can result in pressure imbalances in the fuel tank, which can cause the gas pump to shut down too soon.

Do You Need to Turn Off Your Engine When Getting Gas?

Yes, you need to turn off your engine when getting gas. It is only wise to do this to prevent any problems. However, technically you can keep it on though. While you can technically keep your automobile running, there is little possibility of negligible risk.

An example is an explosion that could occur if gasoline vapors come into contact with static electricity.

Conclusion

We have discussed the possible reasons your gas tank won’t fill and the quick fixes in our distinctive article.

Let’s have a quick recap.

• Your gas tank won’t fill because something is wrong with your evaporative emissions control system.
• The possible solutions for the gas tank not filling are first to check the gas cap, then clean the EVAP system, change the defective EVAP components and check with a diagnostic tool.
• You can’t overfill your gas tank because the fuel can overflow and begin to spill on the ground, which can also be risky.
• Your gauge is reading empty even when your tank is full because there is an issue with your gauge.
• You must turn off your engine when getting gas to prevent any problems.

A blocked or malfunctioning EVAP system is the most frequent reason for a gas tank that won’t fill. It can be resolved by cleaning the system or changing a broken component.