@Top_Fuel, question about refuelling (How are you often adding 31L to a ~28L tank?)

[Top_Fuel]

The fuel gauge is calculated on recent MPG, not tank or overall.
Gauge is based on level remaining and economy of last 50-100km or so.

Interesting. The owner's manual doesn't mention any connection between fuel economy and the fuel gauge. But that's good to know!



My car is driven with a pretty consistent driving style so I would never notice this.

[nickels]

Jeez thats a pretty wonky fuel gauge system we have on our Mirages. Ah well, I just put $10 every Sunday and ride around with a permanent 60% filled tank.

It's all gauges now that it's all computer controlled. It knows what is in the tank, and uses recent economy to decide DTE. Long gone are the days of a float bouncing your fuel gauge needle over speed bumps.

[Eggman]

Interesting. The owner's manual doesn't mention any connection between fuel economy and the fuel gauge.

Yeah, that sounds fishy to me too. Distance to Empty, yes. Fuel gauge, no.

[Space Wolf]

It's all gauges now that it's all computer controlled. It knows what is in the tank, and uses recent economy to decide DTE. Long gone are the days of a float bouncing your fuel gauge needle over speed bumps.

That cannot be true. How could the computer know if I filled it up at the gas station, or only filled for €10?

[Fummins]

There is a float in the tank still but it doesn't bounce the gauge like they used to do 20 years ago. There are usually baffles in the tank that kinda help slow down the fuel slosh a bit but mostly to help the pump from running dry when low on fuel.

If I were to take a shot in the dark I'd say the computer would know how much fuel is in the tank by asking the sending unit what's going on back there. I'm still not sure if that little pill looking thing on the side of the pump is a low fuel sensor or a fuel temp sensor? I'm now thinking fuel temp.

Edit: Mystery solved it's a temp sensor. The the warmer it gets the less resistance to ground it has. I think I posted somewhere that it was a low level sensor or something stupid. I guess I'll be a good dummy and go fix my mistake. Now I'm curious what happens if you just ground out that one sensor wire to make the car think the fuel is hot?

[Mark]

That cannot be true. How could the computer know if I filled it up at the gas station, or only filled for €10?

I have my doubts like Space Wolf, but don't mind being wrong either.

The gas gauge doesn't seem that sophisticated to me, & I have never seen fuel segments reappear while my driving changes. It seems more like 8 segments represent approximately 8 gallons of gas. When the last segment is gone, you have about one gallon of fuel left. One gallon left doesn't seem like much, but it's more of a percentage in a 9.2 gallon gas tank verses a 15+ gallon gas tank.

Obviously, some type of programming computes mpg ratings. If someone finds what's really going on, I would enjoy reading that. I am just speculating myself, but I just don't think the gas gauge is that sophisticated. Unlike many cars that give a mileage to empty readings, I don't sense the Mirage is doing that for us.

[stevedmc]

Ya'll are really over thinking how the fuel gauge works. The fuel pump has a fuel sending unit on it that consists of a float. As the tank runs low, the float drops. I know this because I have a spare fuel pump sitting on the shelf.

The ECU has software built into it that acts as a buffer to slow down the speed of the reading. Think of it this way, without a buffer, the gas gauge would instantly drop as soon as you went up a steep hill due to movement of the float. The gauge would then instantly read high as you go down the same hill.

My Delorean has an older style fuel sending unit that does not have any software built into it to dampen/buffer the signal going from the sending unit to the gas guage. When I go down hill, my tank reads high. When I go up hill, my tank reads low. This is normal and I understand why.

The newer Delorean fuel pumps actually have a fuel sending unit built into them. These sending units connect to a logic box that interupts the signal before it reaches the fuel gauge. The job of the logic box is to dampen/buffer the signal so it doesn't bounce all over the place as the car goes up and down hills. I don't have one in my Delorean, but from what I've been told, the logic box works very well.

Our cars run very similar software that keeps the gas gauge from bouncing all over the place.

[Dirk Diggler]

Ya'll are really over thinking how the fuel gauge works. The fuel pump has a fuel sending unit on it that consists of a float. As the tank runs low, the float drops. I know this because I have a spare fuel pump sitting on the shelf.

The ECU has software built into it that acts as a buffer to slow down the speed of the reading. Think of it this way, without a buffer, the gas gauge would instantly drop as soon as you went up a steep hill due to movement of the float. The gauge would then instantly read high as you go down the same hill.

My Delorean has an older style fuel sending unit that does not have any software built into it to dampen/buffer the signal going from the sending unit to the gas guage. When I go down hill, my tank reads high. When I go up hill, my tank reads low. This is normal and I understand why.

The newer Delorean fuel pumps actually have a fuel sending unit built into them. These sending units connect to a logic box that interupts the signal before it reaches the fuel gauge. The job of the logic box is to dampen/buffer the signal so it doesn't bounce all over the place as the car goes up and down hills. I don't have one in my Delorean, but from what I've been told, the logic box works very well.

Our cars run very similar software that keeps the gas gauge from bouncing all over the place.

[Mark]

Ya'll are really over thinking how the fuel gauge works. Our cars run very similar software that keeps the gas gauge from bouncing all over the place.

Our recent discussion was about post #39. Someone is claiming the gas gauge reading is based on - "The fuel gauge is calculated on recent MPG, not tank or overall."

I have never owned a fancy vehicle. All of my vehicles have base trim levels of any brand/model. The Mirage fuel gauge is quite simple & seems quite accurate. The 8 segments on the fuel bar seems to represent approximately 8 gallons of fuel (in a 9.2 gallon fuel tank). I want a fuel gauge to tell me how much gas I have left. That's all I need it to do, & I feel the Mirage fuel gauge does that quite well.

[Eggman]

Ya'll are really over thinking how the fuel gauge works.

It's what we do here.