3 Symptoms of a defective fuel delivery unit
One of the indicators on your dashboard that you rely on more than you think is the fuel gauge. It’s a vital part of making sure your vehicle stays on the road, and you probably take it for granted. But behind every fuel gauge is a fuel delivery unit that ensures it works properly. So how do you know when your fuel delivery unit will fail, what caused it to fail, and how much it will cost to replace?
What is a fuel delivery unit? Fuel senders have many different names. Other commonly used names include fuel level sender, fuel gauge, and even float gauge. Regardless of what you call it, the fuel sender sends a signal to your vehicle’s fuel gauge, letting you know how much fuel is currently in the tank.
Symptoms of a Bad Fuel Sender If you have a problem with your fuel sender, there are some obvious symptoms that you should not overlook. These symptoms are quite obvious and easy to recognize, but you should rule out a bad fuel gauge before replacing the fuel sender.
1) Fuel Gauge Abnormality
If your fuel gauge is broken and won’t show any readings, you may have a problem with your fuel gauge. This can happen if the float moves more than it should or if the variable resistor in the fuel gauge isn’t working properly. When this happens, the signal from the fuel gauge can change quickly, causing the fuel gauge to behave very erratically.
2) Fuel Gauge Readings Are Incorrect
If the readings don’t match up with what’s actually in the tank, you may have a problem with your fuel gauge. However, keep in mind that the problem may also be with the fuel gauge itself. Therefore, it is a good idea to test your fuel gauge before replacing it.
3) Stuck Fuel Gauge
One of the most common causes of a fuel gauge failure is when the fuel gauge gets stuck in a specific position. In this case, the fuel gauge registers no change regardless of whether the tank is full or empty. The fuel gauge usually gets stuck in the full position, but it can get stuck in any position.
What causes a fuel gauge to fail?The main reason for a fuel gauge to fail is aging. The part of the fuel sending unit that is most likely to fail is the variable resistor. Over time, fuel can cause the resistor to stick or begin to corrode. Even small changes can affect the fuel sending unit.
It is also possible that something has gotten between the variable resistor and the metal rod, causing it to stick. In this case, the fuel gauge will always show the same value, regardless of the amount of fuel in the tank. Using only high quality fuel can reduce this risk, but over time the metal rods can corrode and become stuck in certain positions.
How does the Fuel Delivery Unit work?The Fuel Delivery Unit consists of three main components. The first part is the “swimmer”. The float is a simple piece of buoyancy material that will not break down in fuel.
As for the metal rod, the name says it all: it’s a thin metal rod that connects the float to the variable resistor. The important thing about the metal rod is that it can move with the swimmer.
The float must always be above the fuel; the metal rod moves, allowing the float to move to the correct position in the fuel tank depending on the current fuel level. The final part of the fuel sending unit is the variable resistor.
The variable resistor receives a small signal voltage from the vehicle battery and reduces the signal by adjusting its resistance depending on the vehicle’s current fuel level. The vehicle’s computer receives the signal, converts the voltage to a fuel percentage, and sends this to the fuel gauge.
Sending Unit vs. Fuel Pump
When you think of a fuel sending unit, you might think of a fuel pump. This is because the term “sending” in the name of the fuel sending unit is a bit misleading.
- The fuel sender doesn’t send fuel, it sends a signal that tells the computer how much fuel is in the tank.
- The fuel pump sends the fuel requested by the computer to the combustion chamber.
- The fuel sender has nothing to do with this process, it just tells you how much fuel is in the fuel tank.
