Why is My Fuel Tank Not Filling Up?
An indication of a low fuel level on the fuel gauge prompts you to rush to the nearest fuel station to fill up your tank. Ideally, upon filling the fuel tank, you expect the needle on the fuel gauge to climb up. However, there are instances when the fuel tank is not filling up because the fuel pump shuts off. This can happen due to multiple reasons, the most common of which is a faulty EVAP. Here you will find all the reasons for a fuel tank not filling up and their fixes.
Fuel Tank Not Filling Up – Causes and Fixes
Upon filling the fuel tank, the air in the tank displaces to make space for incoming fuel. Modern cars are equipped with an EVAP – Evaporative Emissions Control System, designed to trap the fuel vapours to prevent polluting the atmosphere.
The EVAP transfers the trapped fuel vapours back to the engine for burning via a process called purging. When the engine is turned off the purge valve remains closed. Upon starting the engine, the valve opens and allows the stored vapours in the EVAP to travel to the engine to be burned off.
When the EVAP gets faulty or clogged, it can result in filling a fuel tank incompletely. Besides that, there are multiple reasons for a fuel tank not filling up which are detailed below.
Reasons for Fuel Tank Not Filling Up
The various reasons for a fuel tank not filling completely usually revolve around issues with the EVAP. Let’s have a look at them.
One of the most common reasons for a fuel tank not filling up is because of a clogged EVAP system. Due to ill-maintenance of the car, debris and dirt can build up in the compartments or hoses of an EVAP system.
Therefore, the EVAP gets clogged, unable to trap further fuel vapours. As the fuel vapours remain in the fuel tank, they pose troubles in filling the fuel tank correctly.
The EVAP is a sophisticated car system, made of different components and car sensors. Failure of any of these valves and sensors can affect the functioning of the EVAP. A faulty EVAP can also be due to damages, such as cracks and leaks in the system or due to a bad fuel tank pressure sensor. For that reason, the EVAP becomes unable to trap the fuel vapours efficiently, leading to fuel-filling problems.
Bad EVAP Canister
The EVAP canister stores the fuel vapours until the engine is started to further transfer them for burning off. A bad evaporative emission control canister shows several signs to get detected. It creates high pressure in the fuel tank which stops the air from passing while the fuel is filled. For that reason, the fuel pump shuts off before the tank is full.
You may also experience a petrol smell in the car due to damage or crack in the EVAP canister. Other symptoms of a bad EVAP canister include:
- Illumination of the check engine light on the car dashboard
- Poor fuel mileage
- Poor engine performance
- Hard car starts
- Rough idling
How to Fix a Fuel Tank Not Filling Up
Despite many factors for a fuel tank not filling up, there are a few tricks you could use to nib those issues in the bud. Let’s have a look at them.
Check the fuel cap
The foremost way to fix a tank from not filling up is to check the fuel cap. Make sure the fuel cap is tightened enough to prevent any leaks from the fuel system. Also, check if the fuel cap is damaged or cracked. If that’s the case, you will need to replace the fuel cap.
Fortunately, fuel caps are economical and can be found at any shop selling auto parts. You can also explore auto parts at reasonable prices from these car parts and accessories for sale in the UAE.
Clean the EVAP system
If you find the fuel cap in optimal conditions, try cleaning the EVAP system next. Doing so will remove any debris or dirt that might have stopped the EVAP from working properly.
To clean the EVAP yourself, use a wire brush and a can of compressed air. Use the compressed air to blow the dirt from the compartments of the EVAP system. Next, use the wire brush to scrub off any remaining dirt. If you find the process difficult, you can always get it done by a professional auto mechanic.
Replace the faulty components
You can also fix the fuel-filling problems by checking for faulty components in an EVAP system. Try checking the EVAP’s charcoal canister, vent valve, and purge valve. It can be one of the reasons why is the fuel tank not filling up.
If unsure of the damaged component, take your car to a professional mechanic for a thorough inspection. They might be able to diagnose the damaged component and further replace it to fix the issue.
Check with a diagnostic scan tool
The quickest way to detect fuel-filling problems is by using an OBD car scanner. The car diagnostic scan tool is a handheld device that reads the codes stored on the car’s computer. To use the scanner, connect it to the car’s OBD-II port under the dashboard.
Once the scanner is connected, start the car engine and let the scanner detect the issue.
Why shouldn’t you overfill your fuel tank?
Overfilling the fuel tank can cause the fuel pump to shut. Once the fuel pump gets shut, the incoming fuel can get into the EVAP canister, clogging it up. A bad EVAP canister needs to be replaced immediately.
How often should you check the fuel cap?
It is advised to check the fuel cap regularly for a loose or damaged cap. You may check it when filling up your tank to ensure that the cap is tightened enough to prevent any leaks.
That’s a wrap on the reasons and fixes for a fuel tank not filling up. Generally, the common reason for a fuel tank not filling completely is a damaged EVAP system. However, it can be detected and tended to by practising the fixes discussed above.
Nevertheless, if despite regular car maintenance, your car is posing recurrent issues, it is better to switch to another car. You can pick any of these affordable, used cars for sale in the UAE that best suit your liking.
Stay tuned to the UAE’s top auto blog for more information on car parts.