Car Repair 101: Troubleshooting a Broken Fuel Gauge

There’s nothing more aggravating and annoying than driving your Vauxhall down the motorway, only to run out of petrol. This problem becomes even more annoying when your fuel gauge tells you there is fuel still in the tank. You begin to question what the problem actual is. After all, your fuel gauge wouldn’t lie to you, would it? The issue has to be other car parts. Something under the bonnet must be failing, preventing you from getting home or to the office or even to the store to get groceries.

Unfortunately, fuel gauges can lie, presenting you with inaccurate readings and sending you on a wild goose chase attempting to discover what Vauxhall parts are causing problems. There could be multiple reasons behind this failed car part as well.

History of the Fuel Gauge

It wasn’t until 1904 that the first float arm petrol gauge was installed by manufacturers. This gauge has a hinged arm with a float mounted to it capable of moving a mechanical pointer so you could see just how much fuel was left in your tank and fill up before you ran out. Over time, this idea was taken steps further thanks to electrical systems that connected the arm to a rheostat. Because of this, fuel gauges were able to be electronically operated and mounted to the dashboard of a vehicle. Today, this is the same principle used.

Types of Fuel Gauges

Three different types of fuel gauges are typically used in cars, depending on their ages. Those built before the early 1980s typically have analogue resistance gauges. Cars manufactured in the 1980s usually have analogue magnetic fuel gauges. Modern vehicles introduced after the 1980s have graphic or digital electronic fuel gauges.

• Analogue Fuel Gauges- These types of gauges have heated bimetal strips that move the indicator needle on your Vauxhall’s fuel gauge. As current flows through the gauge, this strip is heated and expands. The amount of expansion determines the movement of the needle.

• Magnetic Fuel Gauges- Introduced after analogue fuel gauges, these gauges have a magnet located at the end of the needle. Three coils create a magnetic field in which the magnet floats. These car parts often provide more accurate readings than analogue fuel gauges and respond faster to fall or rising fuel levels.

• Electronic Fuel Gauges- These types of Vauxhall parts use LCD or vacuum fluorescent graphic displays to show you how much petrol is left in the fuel tank. They contain a module that helps to monitor how much current is in the sending unit. Many display “E” for empty, “F” for full and “1/2” for half a tank depending on how much fuel is present. Most also indicate your speed and mileage on the odometer.

Diagnosing a Failing Fuel Gauge

If your fuel gauge is behaving erratically, always reading the same or not reading the fuel level in your fuel tank at all, there could be several issues causing the problem. Here are just a few.

• Fuel Sender Feed Wire- One of the most common causes for problems with this car part is a damaged fuel sender feed wire. To diagnose this problem, find this wire. It should be located close to the fuel tank and be a tan colour. Disconnect the wire and turn on the Vauxhall. Wait a few seconds and see what the gauge reads. With the wire disconnected, the gauge should read full. Touch the wire to a ground and the gauge should respond by reading empty. If this does not happen, the gauge is bad or the wire has been damaged and must be replaced.

• Bad Fuel Sender- If the wire produces the correct results, the problem could be a bad fuel sender. Use a multi-meter to measure the amount of resistant to a grounded source. At empty, it should read zero to two ohms, at half it should read about 40 ohms and at full, the tank should read 84 to 88 ohms. If these are not correct, the sender is the Vauxhall part that needs to be replaced.

• Malfunctioning Gauge- When both the fuel sender and fuel sender feed wire are alright, the issue might be the gauge itself. Disconnect it from the dashboard and clean the connection thoroughly. Once cleaned, go through fuel sender feed wire diagnosis steps to see if the gauge is working correctly. Make sure you clean and reconnect the Fisher connector in order to diagnose this car part correctly.

• Electronic Checks and Cluster Codes- In many vehicles, diagnosis codes can be used to determine if the fuel gauge is malfunctioning due to an electronic problem. Your owner’s manual may provide you with a way to perform self-checks to see what the problem behind the failing fuel gauge is. However, in many cases you may need to take your Vauxhall to a professional for a proper diagnosis.

Seeking the Help of a Professional

Diagnosing fuel gauge problems yourself can help you save time and money, but only if you know exactly what you’re doing. Repairing these Vauxhall parts can be dangerous if you’re inexperienced, and you may not determine the cause of the fuel gauge issue if you aren’t sure of the correct steps to take or if you don’t have access to the right tools.

If this is the case, don’t wing it. Consulting with a professional who can look over your Vauxhall quickly and assess the various car parts associated with the fuel gauge is essential. By leaving the problem in the hands of a professional, you can prevent mistakes you might make yourself, saving money and time.

Is your fuel gauge not working? There could be many reasons behind this car part failure. Always consult your owner’s manual first to determine what kind of fuel gauge your Vauxhall has and if there are any instructions provided by the manufacturer on how to repair it. Then, determine if you have the skills and tools necessary to properly diagnosis the issue. If not, rely on the expertise of a professional.