Hello I bought 1998 E39 523i engine m52tub25 with 5 gear steptronic gearbox
Here she is =))
I have trouble with fuel consumption
I look in many catalogs and its say that in city there must be 15liter for 100km
But it goes to 18 even sometimes computer say 19-20 liter
When I bought the car i changed oil (oil filter as well ofc) air filter, fuel filter
It had a vibration and strange noise when i push the throttle so I plugged it into the computer and it show that it was getting more air than it should
so I when to service and they find out that there was a problem with Intake Boot, this one >>>
It was damaged had several holes, so i replaced it and problem was solved
after that I plugged it into the computer to check if there was any problems, but there was no errors.
I have some cash problems =D so i cant just drive it service and fix it.
many people told me many reason why i get this kind fuel consumption
1) Spark Plugs problem
2) I have 18" rims and they are wider and heavy than the stoke rims so car needs more power to roll them so it consumes more fuel. rims looks like this >>>
3) Typically I drive to my office at the morning and then back to home, so i don't drive a lot. I am newbie and this is my firs car and i dont drive fast, 60km/h max on the streets and sometimes on the open roads max 80km/h The distance from my house to my office is 2km, so its a very short distance and some people say that engine dose not get wormed up before i get to my office. Also when going home its cold and also dose not get wormed up before i reach my home. so typically i drive with cold engine and that's the reason why i get such a bad fuel consumption. it goes max at the end of the blue mark before i get to office or to my home, like this >>>
4) Some say that there maybe a another hole maybe in another boot or something like that and that's why it burns so much fuel and there is a smoke test and with that you can find the hole
5) Some say its because of MAF sensor. before i changed the intake boot we find the error when connected it to a computer. the error was with MAF sensor on high rpm at 5k or 6k dont remember exactly, but as i already said above, after i replaced intake boot i did not find any errors after that
6)some say that its because of winter =/ its sometimes -3 or -5 max outside
So I really want to know is it normal to have such fuel consumption? 18-20 liters for 100km?
If its not normal then can you please advice me what to do? I mean if go to a service they will start to change everything, it does not matter if its damaged or not, they will still tell me that that's the reason and i have to change that part and at the end i will end up spending lots of money and nothing will change. yes i don't trust them because they are doing that all the time =/.
P.S sorry for my English and thanks in advance