My 18is is consuming way to much fuel...

[MTD]

With the O2 disconnected the car should get worse mileage unless the sensor were totally broken.

Look under the wiring cover where the three relays are housed in the engine bay. Check to see if there are two single round connectors present, and if they are plugged in, or unplugged.

What i was told was that if the o2 sensor was in bad shape i could test it by doing this. If i got better mileage without it, it's toast. By the way, i deleted my cat.

I didn't catch what you said in the last paragraph. Pics? Why do you want me to check this?

[roguetoaster]

With the O2 disconnected the car should get worse mileage unless the sensor were totally broken.

Look under the wiring cover where the three relays are housed in the engine bay. Check to see if there are two single round connectors present, and if they are plugged in, or unplugged.

[MTD]

hey guys i come bearing good news! I tested a tank with my lambda sensor disconnected, and it dropped my consumption from 10.5 to 9.2 l/100!! What a difference! When i put in a new lambda sensor i can expect this value to drop even further right?

[5Toes]

my m42 in great operating order, rebuilt head from a local ex-racer, and 155k is 180psi cold on a compression test. I suspect 200-210psi when hot but have not checked mine yet

[MTD]

It's messing with me not being able to figure out why im getting bad mpg. Anyways, i'm ordering a chip in the next days, that should enhance the mpg a bit. Not the way i would like it though, i would like it to have a decent mpg on it's own.

Any tips are welcome

[d_elson0]

27-29mpg here. One day I'll try to better that. Maybe it's the funds style 5s or wheel bearings.

What's the compression numbers we would like to see on these anyways?

[MTD]

32mpg (Imperial) or maybe a bit more.

That's 8.8l/100, very good mpg...

[unixnerd]

The best mpg I ever got in my 318iS was about ten years ago on holiday with my mother in the far north of Scotland, got 450 miles from a single tank!

Usually I average around 32mpg (Imperial) or maybe a bit more.

[MTD]

No i did not. I probably should. any other tips?

[MVincken]

I think you did the conversion wrong, maybe u used uk mpg or something. But 10 l/100 is 23.5 american mpg.
It still is high anyway. I use 95 octane european gas (don't know exactly what it converts to in "american" octanes, but i think its 91. I don't carry nothing at all in the car, just me and half the time a single passanger. I really can't find whats wrong, plus it's a shame for an engine with just 130000kilometres....




Welp, if you do find the problem let me know....

As far as i know, octane is octane. maybe they have other additives in the US fuel. but in europe you should expect better mileage because of the better fuel.

have you done a compression check on your cilinders?

[MTD]

Cruising mileage can be impacted by total wheel/tire height. In that respect it's all about revolutions per mile.

A cone filter could actually improve mileage in some cases as it often draws warm air in to the intake versus cold air. Thus a less dense air charge means less fuel injected/less total power. It's all dependent on your specific circumstances of course.

In any case, there's something seriously wrong with your car or engine when an M42 is getting sub 18 MPG. What fuel are you using again, do you carry a lot of stuff in the car regularly?

I think you did the conversion wrong, maybe u used uk mpg or something. But 10 l/100 is 23.5 american mpg.
It still is high anyway. I use 95 octane european gas (don't know exactly what it converts to in "american" octanes, but i think its 91. I don't carry nothing at all in the car, just me and half the time a single passanger. I really can't find whats wrong, plus it's a shame for an engine with just 130000kilometres....

Mines doing the same does 260-280 miles on a tank. Only around 20 mpg. A previous owner 4 years ago got around 400 miles on a tank. No clue what's happening.

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Welp, if you do find the problem let me know....

[sandrune]

Mines doing the same does 260-280 miles on a tank. Only around 20 mpg. A previous owner 4 years ago got around 400 miles on a tank. No clue what's happening.

Sent from my HTC6535LVW using Tapatalk

[roguetoaster]

Cruising mileage can be impacted by total wheel/tire height. In that respect it's all about revolutions per mile.

A cone filter could actually improve mileage in some cases as it often draws warm air in to the intake versus cold air. Thus a less dense air charge means less fuel injected/less total power. It's all dependent on your specific circumstances of course.

In any case, there's something seriously wrong with your car or engine when an M42 is getting sub 18 MPG. What fuel are you using again, do you carry a lot of stuff in the car regularly?

[MTD]

Yeah sorry, i always forget to come back and report.
The fuel comsumption did drop, to 9,8l/100km. Much better, but i still it's too much, for the kind of driving i do (30% city, rest is crusing at 90kph).
I did put on some new 16" wheels after that and the fuel rised to 10,2l/100, don't know why...

I really don't know what to check for, what do you guys recommend?
Furthermore, my next mod is putting a conical air filter, and that should rise the fuel consumption even more right?

[MVincken]

any news?