P1447 and gas gauge SLOW to respond to a fillup

So my X3 threw a P1447 code. I noticed the SES when I got into the car after a fillup. What was weird was that the gas gauge still read nearly empty even though I was sure I had filled it up. Over the next 40 miles of driving (I was on a long trip), the gas gauge SLOWLY rose up to normal.

This gas gauge thing happened once before on a long trip but I didn't get a code that time.

Any ideas?

I had the slow gauge before:

http://www.bimmerfest.com/forums/sho...d.php?t=654601

Ended up being not a full tank of gas and when I went back to refill up about a gallon more went in and problem went away instantly. Haven't had it since. My first thought was fuel filter though.

I think p1447 is an evap code. Could be gas cap or charcoal canister related perhaps??

Just FYI, P1447 is "Diagnostic Module Tank Leakage (DM-TL) Pump Too High During Switching"

Clearly these two are related somehow. Incidentally, I'm not someone who "tops off" the tank.

I'm thinking I'll just clear codes and hope it goes away unless someone has a better idea...

run some Techron through it--I've had the slow gauge problem a few times but no codes. Techron seems to help.

+1

Sent from my DROID X2 using Bimmer App

Yep ^^^ what they said.

What I neglected to mention when it happened to me it was that I didn't get a full tank and it was not at chevron...tsk tsk on me..

When I added the extra gallon to get it full it was at chevron with techron and the problem went away immediately.

It's most likely a dirty fuel sending unit and there are tons of reports of techron cleaning it up.

+1

and if neither Chevron gas nor Techron concentrate is available in your area, get a bottle of BMW Fuel System Cleaner from the dealer as it is re-labelled Techron.

As is the G.M. Fuel Treatment Plus (or some similar name).