Gas Gauge Fix?

[g huns]

So my gas gauge hasn't worked for a long time. Always reads full. Haven't cared enough to pull the back seat out, pop the top and dig around. Just drive it 300 miles and fill er up. A couple random times, it has worked briefly when I start the car up, but after shutting her off and starting up again, back to full and stuck there.

Last week, I see a couple drops of coolant on the floor in the area that indicates a rear coolant flange leak. I pop the hood and snoop around and find that the leak is from the coolant temp sensor in the rear coolant flange. Cool. Easy fix. Yea for me. I order a genuine Audi sensor, o-ring and clip.

Saturday, I pull out the old one, put in the new one, top off coolant and burp. Like I said, easy. I look at the old sensor and notice the green plastic part spins freely in the brass base. That can't be good. I also notice the lack of 4 rings on it. I remember that I bought the rear coolant flange and sensor back when I first got the car and didn't know enough to buy the genuine Audi sensor. I pat myself on the back for being a good Audiziner and jump in to move it.

I look down and see the fuel gauge at 3/4. What the hell? Hasn't even worked randomly in quite awhile. I shut it off and start it back up. Still reading 3/4. I drive it Sunday, and again today, and it's still working.

I can't say my problem started the day I put the non-Audi coolant sensor in, but it was around that time. I just know with a 4 ringed senor, it's working again. For those of you who have forgotten more about the inner, electrical working of these cars than I'll ever know, does this make any kind of sense? Is it pure coincidence?

[ECS Tuning-Audi]

Likely pure coincidence.

The nature of the fuel sending unit it could easily get hung up and cause it to not read properly. Then simply random jarring the float around could get it unstuck and back to normal.

Jason

[Let it snow]

Interesting. Both the fuel level sender and rear coolant sensor are inputs for the instrument control module. It would be interesting if a faulty coolant sensor could somehow (however unlikely) affect the fuel gauge reading. Let us now if the gauge keeps working.

[old guy]

If you changed your fuel pump this may be pertinent: Clicky click®

[g huns]

If you changed your fuel pump this may be pertinent: Clicky click®

Nope, never rooted around in there.

I knew it was too good to be true. Worked fine last night on the way home. This morning, gauge went straight back up to full.

The other funny thing is the miles to go display on the DIS always reads correctly. I assume it's tied to a different sensor than the gauge.