Gas Pump Keep Stopping When My Tank Isn’t Full: The Causes and Fixes

by

“Gas pump keep stopping when my tank isn’t full.” Many drivers complain of the same phenomenon and are at a loss for what causes it.

Gas Pump Keep Stopping

In this article, we’ll discuss why a gas pump will stop working midway. We’ll also explain how to fix the problem and answer pressing questions on the matter.

Why Your Gas Pump Keeps Stopping When the Tank Isn’t Full

Your gas pump keeps stopping when the tank isn’t full because of the wrong type of fuel or because the gas pump detects the tank is full and automatically goes off. The gas pump probably has some minor issues or is incompatible.

Other problems include low fuel levels and a damaged charcoal canister. Fixing some of these problems is easy, while others may require a professional’s touch.

  • Using the Wrong Fuel Type When Refueling Your Car

Using the wrong type of fuel for your car may damage your engine; hence the pump is designed to detect such and stop working. For example, filling a diesel car with petrol will damage it and cost thousands of dollars to repair. This phenomenon has occurred many times in the past as it is easy to forget your car uses diesel and fill it with petrol.

 

Thus, modern vehicles have a sensor that detects the fuel being pumped into the engine. This sensor sits near the neck of the tank and uses a laser to identify the type of fuel you’re pumping into the tank. When it determines that the wrong fuel type is being pumped into the vehicle, it alerts the driver or stops the pump. This intervention helps to save your engine from further damage.

  • Your Gas Tank Is Actually Full

Another reason you might overlook is that your tank is full, so your pump stopped working. You’ll likely think your tank isn’t full when you have a faulty fuel gauge or fuel level sensor. These devices are subject to wear and tear, especially in older vehicles, and may require periodic replacements. Failure to replace it could result in wrong readings, leading you to believe that the tank isn’t full when it actually is.

Gas Pump Problem in Car

Fortunately, you have the gas pump to save the day, as it is designed in a way to detect when the tank is full and stops working. The gas pumps have smaller outlets that let the air out of the tank while pumping fuel.

The more you pump the fuel, the more air exits the tank until the pump detects that the air has stopped flowing out. The gas pump then stops working, saving your vehicle from problems such as poor acceleration due to overfilling the tank. It also stops the fuel from spilling on the floor, creating a potentially dangerous fire outbreak.

  • There’s a Fault With the Fuel Pump

The fuel pump can develop a fault at any time during its operation, which will stop it from working. One common problem is the wear on the pump caused by overuse and improper lubrication. The fuel in tanks lubricates the pump; thus, if your fuel level is low, it won’t properly lubricate the pump. Thus, the pump begins to wear prematurely.

Sometimes, pump components begin to corrode after coming in contact with water and air. The process begins with small amounts of moisture in the tank, eventually affecting the fuel pump, wires and sensors.

The rust then damages these components and flakes off into the fuel, blocking the channels through which the fuel will flow. This is one of the main reasons why your Jeep Grand Cherokee gas pump keeps stopping.

  • Incompatible Fuel Pump

This is similar to using the wrong fuel type. If your fuel pump is incompatible with the fuel in the vehicle, the pump will cease working to prevent damage to the engine. Each fuel type has its designated pump that can only be used by that fuel.

 

For example, gasoline pumps are suited to gas and diesel pumps work with only diesel fuel. Thus, when a diesel pump detects that the fuel inside the tank is gasoline, it will stop pumping to save the engine. That is why the diesel pump keeps clicking off.

  • A Damaged Fuel Pump Nozzle

Most fuel pump nozzles can last about three years, after which they must be replaced. However, many fuel stations try to save money by keeping the same nozzle on after expiration. The end of the nozzle then begins to widen due to overuse. As a result, the fuel doesn’t flow uniformly through the nozzle, and this causes turbulence in the fuel filler pipe of the vehicle.

The turbulence causes the fuel to bounce back from the fuel tank and block the venturi on the fuel nozzle. The clogging of the venturi will prematurely shut off the pump nozzle and prevent it from dispensing fuel. Therefore, if the gas pump keeps shutting off Hyundai, check the nozzle. It could be the source of your problems.

  • The Gas Pump Nozzle Sensor Automatically Shuts Off

Gas pumps have a device at their end that shuts off the fuel flow when it runs back up the nozzle. Usually, this happens when the tank is full. However, some pumps have this annoying habit of shutting off even when the tank isn’t full.

The reason is that gas is filling the tank at a higher pressure than the car can take. If the vapors don’t escape fast enough and the nozzle gets submerged in the gasoline, a vacuum forms in the nozzle and forces the device to shut off the pump.

Fixing a Gas Pump That Shuts Off When the Tank Isn’t Full

Fixing a gas pump that shuts off when the tank isn’t full involves using the right fuel for the right tank. Check the fuel gauge and the fuel level sensor to see if they work properly. You can check the gas pump for damages and fix them.

  • Using the Right Fuel Type

Always ensure that you use the right fuel type for your vehicle. Also, enquire about the fuel a car uses before purchasing to be on the safer side. However, if you accidentally fill your car with the wrong fuel type, you must flush it out and refill it with the right one. First, don’t start the vehicle, as switching on the engine may cause more harm.

Next, push the vehicle to a safe distance and then drain the wrong fuel from the tank. One way to drain the gas tank is to remove the fuel drain tag under the vehicle. However, ensure you have enough drains to catch the fuel.

Once the fuel is drained from the vehicle, call a professional to flush the residue of the wrong fuel left in the gas tank and fuel pipes. The flushing process must be carefully done to prevent or minimize the damage caused by the wrong fuel.

However, all hope is lost if you start your vehicle before realizing you filled the wrong fuel. The wrong fuel can damage the fuel lines, gas tanks, and the engine, which will cost a fortune to fix. Therefore, use the right fuel for your vehicle to avoid damaging it.

  • Fixing a Faulty Fuel Level Sensor

First, you must assess if the fuel level sensor is the culprit. Observing the fuel gauge is one way to tell if the fuel level sensor is faulty. If the fuel gauge is stuck, it shows empty when the fuel tank is full or vice versa; you might want to check the fuel level sensor. The sensor is located in the tank, reads the fuel level, and sends the information to the gauge.

Fixing a Gas Pump That Shuts Off

The fuel gauge interprets the signal and indicates the fuel level with a needle. You’ll need a mechanic to test the sensor for you as it involves removing it from the fuel tank. The mechanic will then connect a white alligator clip to the red cable of a voltmeter. They’ll then connect the end of the alligator clip to the signal post on top of the fuel level sensor.

Next, they’ll connect the voltmeter’s black cable to a yellow alligator clip and connect the other end to the sensor’s body. He’ll then check the reading of the resistance, which should fall within a range depending on the type of vehicle.

If the reading falls outside the range, the fuel level sensor is faulty and requires replacement. Replacing it should cost between $80 and $450, including labor costs and the cost of the sensor.

  • Fixing a Faulty Fuel Pump

Usually, it is the fuel station’s job to fix their faulty fuel pumps. Thus, alert the station’s management whenever you notice a pump malfunctioning. They’ll perform their checks to ascertain the exact cause of the problem and call a professional for help. However, if the pump is automatically shutting off because the fuel pressure is too high, then you need to adjust it.

Frequently Asked Questions

– Is It Better to Pump Gas at a Slower or Faster Rate?

It is better to pump gas at a slower rate because you get your money’s worth. Pumping faster generates more fumes that travel up the nozzle due to the vapor recovery system. That’s why the gas pump keep shutting off Ram 1500.

– What Causes Gas Pump To Stop When the Tank Is Full?

A small device called the Venturi in the nozzle causes the gas pump to stop when the tank is full. When the gas level rises and reaches the end of the Venturi, it closes the air pressure that holds the nozzle’s hand open, shutting off the gas flow.

– What Makes Fuel Finish Faster?

A few things that make fuel finish faster include aggressive driving, overspeeding, and idling for a long time. Also, constantly changing gears and driving at different speeds take a toll on the fuel. Always drive carefully, stay within speed limits and use cruise control on the highway.

Gas Pump Nozzle Sensor

Conclusion

We’ve found the answer to why does the gas pump stop when my tank isn’t full and discovered various ways to fix the problem.

Here is a summary of all the important points:

  • A damaged fuel pump might stop intermittently while pumping gas, and the only way to fix it is to replace it with a new pump.
  • Pumping fuel at a higher pressure can cause the fuel vapors to rise through the nozzle via the Venturi and shut off the pump even when the tank isn’t full.
  • A faulty fuel level sensor can send wrong signals to the fuel gauge, making you think that the tank isn’t full when it actually is, which is why the pump has stopped.
  • A faulty fuel level sensor can only be fixed by a qualified mechanic who’ll test it with a voltmeter and then replace it if the test indicates it is damaged.
  • You should also use the right fuel for your car to avoid damage to the engine and the high costs associated with replacing it.

However, don’t start the engine if you pump the wrong fuel into your car; rather, contact a professional who’ll flush out the fuel. However, if you start the car, you’ll need to buy a new fuel system or a car.

5/5 - (15 votes)
Ran When Parked
Latest posts by Ran When Parked (see all)