Fuel Sending Unit Replacement: When Is The Right Time?

The fuel level sending unit is located in the fuel tank and sends a constant signal indicating the amount of fuel that remains. When the unit fails, the fuel gauge will not operate, and the check engine light may illuminate. The fuel level sending unit rarely needs to be replaced and is not considered faulty often. However, when it does need to be replaced, it can cost between $1,279 and $1,511 for a Jeep Wrangler. The process of replacing the unit involves removing the fuel tank, which can be cumbersome and heavy. It is important to note that carrying gasoline or diesel fuel inside the vehicle or trunk is dangerous, and it is recommended to have it outside the vehicle.

Fuel gauge not working

If your fuel gauge is not working, there are a few things you can try. Firstly, check if there is a fuse for the fuel gauge and see if it needs to be replaced. If all the other gauges are working fine, then the issue is likely with the fuel gauge itself. Another possibility is that the electrical connection behind the dashboard is loose, so try tightening it.

If your Jeep Wrangler has a fuel gauge that is not working and reads empty, there could be a problem with the fuel sending unit. This unit contains a float that detects the amount of fuel in your tank, and it is possible that this float is broken. To replace the fuel sending unit, you will need to drop the gas tank and remove the fuel pump. It is recommended to replace the entire fuel pump assembly, including the sending unit, as repairing only the sending unit can be difficult and may not be cost-effective.

Before replacing the fuel sending unit or fuel pump, there are some troubleshooting steps you can try. Check the connector at the rear of the fuel tank, which is located on the driver's side near the top of the tank. Unplug and reseat the connector to see if that resolves the issue. Use a flashlight to inspect the connector for any dirt or corrosion. If the connector looks clean and the gauge still doesn't work, then the issue is likely with the fuel sending unit or fuel pump.

Additionally, you can try running a cluster diagnostic to see if it responds, as this has been known to fix fuel gauge issues in some cases. If you recently installed a new fuel pump and the gauge is still not working, check the wiring for any potential issues. Ensure that the ground wires are connected properly and there are no shorts in the wiring harness.

If you have a 1997 TJ Wrangler, there is a factory recall for the fuel pump, so it is worth checking with your Jeep dealer to see if this recall has been completed on your vehicle.

Fuel pump working fine

If your fuel pump is working fine but your fuel gauge is not, this could be a sign of a faulty fuel sending unit. The fuel sending unit is an essential component of your vehicle's fuel system, measuring the level of fuel in the gas tank and sending this information to the fuel gauge on your dashboard. A faulty unit will result in an inaccurate fuel gauge.

Symptoms of a faulty fuel sending unit include the fuel gauge getting stuck on empty or full, and the fuel gauge behaving erratically. For example, the needle may move erratically and not provide a stable indication of how much fuel is left. In some cases, a faulty fuel sending unit may cause your engine to stall unexpectedly due to insufficient fuel supply.

If you are experiencing issues with your fuel gauge, it is important to first confirm that the issue is with the fuel sending unit and not another component, such as the wiring or the gauge itself. You can do this by disconnecting and reconnecting the sending unit and observing whether the gauge responds. If you have access to a multimeter and your vehicle's fuel tank, you can also use the multimeter to verify if your fuel sending unit is faulty.

If you determine that your fuel sending unit needs to be replaced, it is recommended to choose a high-quality replacement part from a reputable supplier. The replacement process involves disconnecting electrical connectors, unscrewing the old unit from the tank, and installing the new unit securely before reattaching all necessary components. This task may be labour-intensive, depending on the location of your fuel tank and the ease of access.

Replacing fuel sending unit vs entire fuel pump

Replacing the fuel sending unit and the entire fuel pump are two different tasks that can address similar issues with your vehicle's fuel system. Here is a detailed comparison between the two:

Replacing the Fuel Sending Unit:

The fuel sending unit is a combination of the fuel pump and the fuel level sensor. The fuel pump draws fuel from the tank and pushes it towards the engine, while the fuel level sensor measures the amount of fuel remaining, transmitting this data to the vehicle's fuel gauge. When the fuel sending unit fails, you may experience problems such as engine stalling, difficulty starting the car, inaccurate fuel gauge readings, or even fuel leaks.

To replace the fuel sending unit, you will need to locate the fuel tank access panel, typically under the rear seat or in the bed of a truck. You will then need to disconnect the fuel lines and electrical connectors before removing the old sending unit. The process involves working with fuel and requires safety precautions such as wearing protective gear, ensuring proper ventilation, and avoiding open flames.

Replacing the Entire Fuel Pump:

Replacing the entire fuel pump involves a more comprehensive approach. In addition to addressing the issues related to the fuel sending unit, replacing the entire fuel pump can provide further benefits. It is often recommended to replace the entire fuel pump if you are already experiencing issues with the fuel sending unit, as it can save time and effort in the long run. This is especially true if your vehicle is older and the fuel pump is likely to be nearing the end of its lifespan.

However, replacing the entire fuel pump can be a more complex task, depending on the make and model of your vehicle. In some cases, you may need to drop the fuel tank to access the pump, which can be a more involved process. Additionally, it is crucial to use a fuel pump specifically designed for your vehicle's make and model. Using a generic fuel pump may lead to performance issues or damage to your fuel system.

In summary, replacing the fuel sending unit focuses on addressing issues with the fuel gauge and ensuring proper fuel delivery to the engine. On the other hand, replacing the entire fuel pump provides a more comprehensive solution and can be a more efficient approach if your vehicle is older or if you anticipate future issues with the fuel pump. It is important to weigh the benefits of each option and consider factors such as the age of your vehicle, the accessibility of the fuel pump, and your budget. Ultimately, the decision should be made based on your specific circumstances and the advice of a qualified mechanic if needed.

Fuel tank removal

The following is a step-by-step guide on how to remove the fuel tank on a Jeep Wrangler TJ. This process will be similar for other Wrangler models, but there may be subtle differences.

Step 1: Prepare the Vehicle

Before starting, ensure you have a floor jack that can support the weight of the fuel tank. Run the tank as low as possible on fuel to reduce the weight and make it easier to handle. Place the jack under the tank to support it.

Step 2: Disconnect Hoses and Vent Tube

Remove the filler hose and vent hose from the filler spout at the rear of the vehicle. These hoses are located behind the filler spout, where you fill up your vehicle with fuel.

Step 3: Remove Skid Plate Bolts

Remove the front and rear bolts holding the skid plate to the frame. You don't need to remove the strap bolts that go over the tank; only the bolts at the front and back of the skid plate need to be taken out.

Step 4: Lower the Tank

Slowly lower the tank using the jack until you can access the other hoses and tubes. You will need to tilt the tank towards the driver's side of the vehicle to manoeuvre it around the exhaust system.

Step 5: Disconnect Remaining Hoses and Tubes

With the tank lowered and tilted, you can now disconnect the remaining fuel hoses and breather tubes. Be careful not to damage any of the hoses or tubes during this process.

At this point, you will have successfully removed the fuel tank from your Jeep Wrangler TJ. You can now perform any necessary maintenance or repairs, such as replacing the fuel pump, sending unit, or skid plate.

Additional Considerations:

• It is recommended to replace the fuel pump, hoses, and gasket while you have the tank removed.
• Check for any signs of rust or damage on the tank, skid plate, or surrounding components.
• Consider upgrading the skid plate to an aluminium one to prevent rust issues in the future.
• If you have a 15-gallon fuel tank, you can modify the filler neck to convert it into a 19-gallon tank.
• Ensure you have the correct tools to disconnect the fuel line connectors, as they can be tricky to work with.

Fuel gauge accuracy

The fuel gauge accuracy of a Jeep TJ can be affected by various factors, including a faulty fuel sending unit, a faulty fuel pump, or electrical issues. In some cases, the fuel gauge may not work at all, while in other cases, it may provide incorrect readings.

If your fuel gauge is not working properly, there are a few things you can try to troubleshoot the issue. First, check the connector on the front driver's side corner of the gas tank and try reseating it a few times, as this is a common issue that can affect both the fuel pump and fuel gauge sender. If that doesn't work, you may need to replace the fuel sending unit or the entire fuel pump assembly.

The fuel sending unit is responsible for sending information about the fuel level to the fuel gauge, and it can become faulty over time due to wear and tear or corrosion. In some cases, the fuel sending unit may be spot-welded onto the fuel pump housing, making it difficult to replace. However, it is still possible to find replacement parts for certain models of Jeep TJ.

If you decide to replace the fuel sending unit, it is recommended to also replace the fuel pump and hoses at the same time, as accessing the fuel sending unit requires dropping the gas tank. It is also a good opportunity to inspect and replace the armour for the fuel tank, as this requires the same process of dropping the fuel tank.

In terms of fuel gauge accuracy, some Jeep TJ owners have reported that their fuel gauge readings can vary by almost 1/8 of a tank when driving on steep inclines. Additionally, the fuel gauge may not always read "E" accurately, and it is recommended to keep a close eye on the fuel level to avoid running out of gas unexpectedly.

It is important to note that the fuel gauge accuracy may also be affected by the specific model and year of your Jeep TJ, as well as any modifications or upgrades that have been made to the vehicle. In some cases, it may be necessary to consult a mechanic or a Jeep specialist to diagnose and resolve fuel gauge accuracy issues.

Frequently asked questions