Fuel Level Gauge Stuck At Empty
 

Ok guys, so a little while ago my fuel level gauge on my 2012 Mazdaspeed3 started acting real sporadic and then stopped working all together. Now about a week before this happened I used an "add-a-circuit" to hard wire my radar detector into my accessory spot in the driver side fuse box. I've heard of people having this problem while using E85 and the sensor itself going out, but I've religiously used 93 OCT only since I bought it brand new in 2012. Any ideas on what could be causing this problem?


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The fuel level sender (basically a variable resistor attached to a float in the tank) is the most common culprit for this kind of thing but it's also worth checking the wiring that goes to the fuel pump.

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Ok that's what I figured. I was thinking the float was maybe gummed up or something. I'll try and find where the wiring starts and ends at and go from there. Thanks


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I'd guess it is the sending unit itself.

You're not going to find much in the way of wiring for the sending unit without getting into the tank. There is a small connection on the top hat that can be accessed by removing the bottom of the rear seat. If there is not a problem there, you'll need to cut a larger access hole to pull the top hat out of the tank. That is the worst part of getting to the fuel level sending unit. Once it's done, you might as well get a 50/50 e85 tune and enjoy the fasts because swapping the sending unit takes like 10 minutes after an access hole is cut. I've replaced mine 3 (or 4?) times now.

That's unreal that someone has not come out with a permanent solution for this issue.


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Seriously the worst part is the initial cutting of the access hole.

It's like a $30 part, so motivation to create a solution is low. There are ideas. A few of which I am considering trying the next time my unit fails.

Fuel sender design isn't great in gen2. E85 is slightly conductive and connectors on the sender are close enough together to cause galvanic corrosion.

Usually the fuel sender doesn't go out easily when you are running petrol only. Are you getting a CEL? When the gauge is stuck it usually trips a CEL. Maybe the center fuel level indicator/odometer display is messed up?

Fuel Level Gauge Stuck At Empty
 

Yes I am. My "Check Engine" light is on. It says fuel level high output I believe. My digital gauge is on zero bars at all times. I did order the unit through my dealership today around 8:30am. They said it'll be in tomorrow.


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This probably would have been good information for the original post.

details....

CEL is always thrown with this apparently common problem...


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A failed fuel sending unit does not always throw a CEL. In fact, I've never gotten a single CEL for it. It simply fails to read accurately. The ECU still thinks it's reading, and displays what it is reporting on the dash, the reading is just incorrect.

So, that would have been good information in the OP since I've likely been directing you to something that is not the cause of your issues.

Have you tried unhooking your rigged up radar detector....just to see what happens?

Once it is completely dead, it will always throw the code. If the reading is just off by some or a lot, it does not throw the code.

Been through 3 of these thanks to full e85 use. Each time the code would only come on once the gauge wouldn't go past 1-2 bars even on a full tank.