b87zod Posted June 18, 2013 Report Share Posted June 18, 2013 Hello guys! I am new here but no matter how deep I have searched the forums I didn't manage to find a solution to my problem. So there it goes: I have an E46 318i 1998 (M43B19) which gives me a lot of headakes with the fuel consumption. In town, medium to heavy traffic, climate control always on it does a maximum of 12 MPGs and this is outrageous. When I bought the car las year it did something like 17MPGs and this is quite normal for that car in that conditions and outside the city it did last year 30MPGs and now more like 19.5MPGs. It has no error codes stored, the MAF and Disa valve are ok, the spark plugs, ignition coil and leads are ok, O2 sensor ok, the car seems to be running great, reving normaly, the only thing that seems strange is that on acceleration if I drive near a wall it sounds like is blowing/sucking air but I didn't manage to find the leak or cracked hose by eye. Is there any possibility to be a problem with my SAP and that generates that low mpg? Please help me because it's driving me crazy and I love that car (just did a total exterior and mechanical overhaul, spent a lot of money and I would really like to solve this problem). Thank you very very much! Link to comment Share on other sites More sharing options...
simonlpearce Posted June 18, 2013 Report Share Posted June 18, 2013 I would pull all of the intake hoses off and thoroughly inspect them if i were you. Have you been keeping an eye on miles per tank and recording this? Link to comment Share on other sites More sharing options...
marc l Posted June 18, 2013 Report Share Posted June 18, 2013 I've got the same engine as you and there is definitely something wrong. Even in london I get 22mpg + Link to comment Share on other sites More sharing options...
mjn Posted June 18, 2013 Report Share Posted June 18, 2013 Also, is it getting upto temp? mit 1 Link to comment Share on other sites More sharing options...
Nick330ci Posted June 18, 2013 Report Share Posted June 18, 2013 You think 17mpg is right for a 318 around town? I get 22mpg in my 330 round town! Something is definately wrong, sorry I can't help you more. mit 1 Link to comment Share on other sites More sharing options...
bungers Posted June 18, 2013 Report Share Posted June 18, 2013 Sounds like it's effectively on choke all of the time which could either be the engine not warming up properly or a major air leak? Link to comment Share on other sites More sharing options...
Marcus Posted June 18, 2013 Report Share Posted June 18, 2013 Have you had it diagnosed on a proper machine. sometimes the top quality stuff finds stuff the hand helds don't. Check all intake hoses...make sure its getting up to temp,not just on the gauge too, check cat hasn't collapsed too. Is performance ok ? Link to comment Share on other sites More sharing options...
dunk1 Posted June 18, 2013 Report Share Posted June 18, 2013 If you have checked the plugs what were they like at the tip. Can you post a photo This may sound really mad but a friend had a fuel consumption issue on a supra a while ago and it was down to his rear calipers beginning to seize. A simple check after you've driven the car is feel for higher temps around the caliper/disc area, hold the back of your hand near to the wheel but don't touch it and see if one or more feel hotter than the rest. Link to comment Share on other sites More sharing options...
Packer Posted June 18, 2013 Report Share Posted June 18, 2013 Are you sure it is actually doing that MPG, or is that just what the on board computer is telling you? I have the same engine as you and I get 22-23 MPG in town (heavy traffic) according to the computer. I thought that was fairly bad... Link to comment Share on other sites More sharing options...
Ginger Posted June 18, 2013 Report Share Posted June 18, 2013 (edited) With the engine running, loosen the oil filler cap, then lift it off of Its seat, if there is a vacuum sucking it down onto the rocker cover, then the ccv valve is fubar'd. Also, airmass meters are notorious to go belly up on these engines, causing overfuelling. Edited June 18, 2013 by Ginger Link to comment Share on other sites More sharing options...
Ginger Posted June 18, 2013 Report Share Posted June 18, 2013 Also, as dunk says, check all brakes (incl handbrake) for binding, and make sure your tyre pressures are good. Link to comment Share on other sites More sharing options...
