320i Using too much Fuel - BMW Forum

Mitch_Medic · 06-27-2009, 12:58 PM

Hey All,

Just bought my first Bimmer a 2005 320i, been driving it for three weeks now and I have been having an issue this last week with my instant fuel economy and my car using too much fuel.

About 2-3 seconds after I give it gas the IFEG (instant fuel economy gauge) moves all the way over and stay s there throughout the 2nd 3rd and 4th gears...its wasting a lot of fuel and Im not getting the torque I need or want when I want it. The problem just appeared after I had new rims and tires put on.

Ive suspected a spark plug or possibly the torque converter but Im no car guru and thought someone may have some insight.

Thanks in advance, any advice is much appreciated.

PS. Also Im getting a bit of a sterring wheel shake around 60 km/h and my dealer says the tires I have on are too soft (Pirelli P6 M+S on a 16' x 7' wheel) so they tend to float out a little ???? Anyone heard of that???

Mitch_Medic · 07-02-2009, 09:56 AM

Found out that the stearing wheel shake was my REAR LOWER CONTROL ARM BUSHINGS, it was a wobble that came in around 60 km/h and didnt go away till after 100km/h...dealer is gonna cover it since they did the saftey on the car.

witeshark · 07-02-2009, 10:05 AM

Glad you have resolved at least that much.

marti5 · 07-02-2009, 10:51 AM

I would very much doubt the torque convertor is the problem, so before you changed you rims was all fine if so, have you put bigger ones on ?, If you have this will effect it as the sensor reads the wheel speed, so by putting larger wheels on the rotation time is longer.

Mitch_Medic · 07-03-2009, 06:09 AM

[i]"I would very much doubt the torque convertor is the problem, so before you changed you rims was all fine if so, have you put bigger ones on ?, If you have this will effect it as the sensor reads the wheel speed, so by putting larger wheels on the rotation time is longer".[/I]

I thought of that because while my rims were being changed out I had my winter rims and tires on and they are a lighter steel rim with not as much width and my car had lotsa pep. Maybe the new rims are heavier??? I also had an electronic rust module put on the car and around that time I noticed I lost the pep.

Is there any way to let the car know that the rotation time is longer?

That being said, I do have 5 series rims on my car but they are the exact same size as any 3 series rims (16 x 7), the 5 series rims were on the car when I bought it a month ago and just recently it has lost its pep, any other ideas, or do you think that is the real issue?

Thanks for posting a reply btw, its much appreciated.

marti5 · 07-03-2009, 07:57 AM

Do you still have your old rims, if so stick them back on and see if it makes any difference then we can eliminate that theory.

Mitch_Medic · 07-07-2009, 01:54 PM

Ok I founf out what the problem was....Man this is exhausting...MARTI5...you were right in a way, the tires werent balanced properly on the car, because they are a lipless rim they need to be balanced with inner wheel weights in stead of on a balancing machine.

The harmonic sensors are being told that the tires are larger due to their improper balancing....its all very technical (which I dont understand hehe), but nonetheless I have had the new rims and tires properly balanced and all is well.

But MARTI5, you were right the tires are a little larger but the dealer says the cars computer will fix that on its own.

Thanks everyone for their posts much appreciated.

Oh and anyone reading these posts, the FRONT REAR KNUCKLE BUSHINGS are a common problem in terms of their wear on the E46/320i, vibrations in your front end around 60-70 km/h is most likely the problem, there is a U-tube video on how to replace them actually.