High fuel consumption

Ovass

Member
Hello guys,

I have a 1.4 petrol A2, 2001 and i have some huge fuel consumption when i'm driving in the city. And when i say huge, i really mean it. It the city it's around 20-22 mpg, but on motorway it's about 56-58 mpg (60-65 mph) and no matter what season is, my heat / AC is almost always on (automatic AC). But i did turned it off for a while to see if there is any difference. The numbers changed to 22-24 mpg / 58-59 mpg, so that is not the problem. I event tried for a while to change gears no higher then 2.5k - 3k max, so i dont push the engine to much. No luck. The air and oil filters are brand new, oil changed, fuel filter also. The one thing i did not changed are the spark plugs because one of them is stucked, but the car always starts very well, it did never made any problems when turning ignition on, not even in the winter at low temperatures. I did test the car with VCDS and it gave a LAMBDA sensor error, but if that is really the problem... shouldn't it have always high fuel consumption?!?! Could it be that at low speeds the engine takes some false air somewhere and at high speeds that gap closes or i dont know?! I'm runing out of ideas and i don't wanna buy the LAMBDA sensor (damn expensive) and to see the same numbers after changing it. So guys... i'm open to any things that i could try. Thank you :)
 
Hi - in my opinion quite likely to be lambda sensor as ecu tells fuel system to increase fuel injector duration I believe if no correct mixture levels recorded so engine is running rich at all times. Do find both your fuel consumption levels crazy though as had my petrol 1.4 over ten years and never got anywhere near those figures around town or on motorway (max around late forties / early fifties when running perfectly)

Cheers Dave
 

Ovass

Member
Hi - well, at first i was thinking the same, but when i got on the motorway and saw that the consumption was more then ok it got me thinking. Why doesn't it have a high consumption on motorways also? And why this difference betwen them? Yes, lambda sensor reports to much air / to low air and the ECU acts after that's sensor readings. My sensor tells that there is to much air and so ECU gives more fuel. But it seems like the sensor feels too much air only when i'm driving in the city, when i'm on motorway the sensor seems to get good readings.... so, damn... i'm lost! :confused:
 
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