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Fuel Usage Is Thru The Roof! 16l/100kms

drifta1600
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drifta1600 Contributor

drifta1600

Posted
Posted

hi all, i hope some one can help me, my 93 mdl r33 skyline auto is using so much fuel its not funny! the only mod is a k&n cartrage fillter thats all!

what i want to know is is the a way i can tune it to get my fuel econemy down? The L/100kms gose up to like 18L/100kms if i floor it every were! is that normal?? Hope some one know what i can do to make it more eficiant..... :-(

PM-R33 Grand Master

PM-R33

Posted
Posted (edited)
The L/100kms gose up to like 18L/100kms if i floor it every were! is that normal??

You answered your own question really.

There is no O2 sensor on the cat, that is a temperature sensor.

GTST's only have one O2 sensor on the dump. However realise that an O2 sensor works by trimming out a bit of fuel when it switches to the cruise map when you sit on a constant speed not if you are constantly varrying the speed. If you are accelerating all the time around town or something than im sorry to say, but welcome to owning a Skyline. Throttle pedal goes down, fuel goes down, simple as that.

Edited by PM-R33
mad082 Grand Master

mad082

Posted
Posted

18L/100km for heavy driving use isn't that bad. it is pretty normal. i used to get similar even driving sort of sensibly.

before you even start looking at other things, think about the following things as they will give you an indication of whether it may be your driving style or something else.

1: even if you don't floor it all the way, when you accelerate are you pressing the accelerator down far enough to make it have full boost?

2: do you do lots of short trips?

3: do you sit on the same speed a lot or is it a lot of start/stop driving where you have to accelerate up to speed often?

4: do you let the car idle to warm up before driving off in the morning?

5: do you live somewhere with lots of hills and often have to take off from intersections at the bottom of hills?

if you answered yes to any or all of those, then even if there is something mechanically wrong with the car causing poor fuel economy, fixing it won't make it much better. questions 1,2,3,5 all applied to me and were the reasons why i got poor economy.

a few other things to check though to see if the car may have a fault.

1: how long does the car take to come up to temp? if you hop in and drive straight away the car should come up to temp within about 5 mins. if the car takes much longer, or never fully comes up to temp then change your thermostat as that can make fuel economy worse.

2: get a multimeter and do a search on here of how to check your o2 sensor, or alternatively borrow/buy a consult cable so you can hook a laptop up to your car and check it on a consult program. you can also use this to reset the self learn codes.

3: if you get really bored, jack up the car and go round and try turning each wheel to make sure you don't have a sticky brake piston. they will always take a little bit of effort to turn, but if 1 is much harder than the rest then you know you may have an issue.

other things to possibly look at would be to get your injectors professionally cleaned and cleaning your AFM.

RB25PWR Proficient

RB25PWR

Posted
Posted
He said gets even worse economy when he drives like that,

DUDE.

Your name suits you. Where did he say that? All he said was that he gets around 18L/100km per tank when he puts his foot down. That's pretty much spot on 300km.

DUDE.

thommo Mentor

thommo

Posted
Posted
Your name suits you. Where did he say that? All he said was that he gets around 18L/100km per tank when he puts his foot down. That's pretty much spot on 300km.

DUDE.

read the thread topic then read his first post.

CARSICK Rising Star

CARSICK

Posted
Posted (edited)

Fuel usage varies too much whilst giving the right pedal the boot.

My R33 uses 12l/100Km in everyday driving & the 328Ci uses 9.7

If I do squirts up 'n down mountainsides, they'll both go up between 30-60%

That tells us nothing

Try filling it up to the brim with 98RON and "zero" the tripmeter

> Go for a long drive on the motorway and baby it (since it's an auto)

> Fill it up again and check the litres needed to refill, against the number of Kms on your tripmeter.

So if you've gone 280 Kms, divide the number of ltres by 2.8 = ___litres/100Km

If your usage is still way over 12l/100Km, then other variables above come into play including the O2 sensor.

Edited by CARSICK
drifta1600 Contributor

drifta1600

Posted
  • Author
Posted
18L/100km for heavy driving use isn't that bad. it is pretty normal. i used to get similar even driving sort of sensibly.

before you even start looking at other things, think about the following things as they will give you an indication of whether it may be your driving style or something else.

1: even if you don't floor it all the way, when you accelerate are you pressing the accelerator down far enough to make it have full boost?

2: do you do lots of short trips?

3: do you sit on the same speed a lot or is it a lot of start/stop driving where you have to accelerate up to speed often?

4: do you let the car idle to warm up before driving off in the morning?

5: do you live somewhere with lots of hills and often have to take off from intersections at the bottom of hills?

if you answered yes to any or all of those, then even if there is something mechanically wrong with the car causing poor fuel economy, fixing it won't make it much better. questions 1,2,3,5 all applied to me and were the reasons why i got poor economy.

a few other things to check though to see if the car may have a fault.

1: how long does the car take to come up to temp? if you hop in and drive straight away the car should come up to temp within about 5 mins. if the car takes much longer, or never fully comes up to temp then change your thermostat as that can make fuel economy worse.

2: get a multimeter and do a search on here of how to check your o2 sensor, or alternatively borrow/buy a consult cable so you can hook a laptop up to your car and check it on a consult program. you can also use this to reset the self learn codes.

3: if you get really bored, jack up the car and go round and try turning each wheel to make sure you don't have a sticky brake piston. they will always take a little bit of effort to turn, but if 1 is much harder than the rest then you know you may have an issue.

other things to possibly look at would be to get your injectors professionally cleaned and cleaning your AFM.

Thanks so much for your awsome response to my questions :-)

Q1: i try not to get full boost every were, even though full bost is only 5psi!

Q2:I do alot of short trips

Q3:a litle bit of both, start stop and h/way cruisen

Q4: na i dont let the car warm up, it warms up pretty quick. i do have a 52mm alloy radiator in it though and it dose run pretty cool, is that a bad thing? i drove it down from sydeny to melb when i bought it and i was geting 10L/100kms siting on 100km/h i was real real babying it though because it had a cracked radiator full of stop leak LOL :-)

Q5: na dont drive on many hills.

Thanks for you great help :-) much appreciated :-)

**RB2530** Proficient

**RB2530**

Posted
Posted

Check the tuning of your right foot....

Nah seriously take your handbrake off...

Nah even more seriously, make sure there is no unexplicable drag on your car by parking it on a flat (level) smooth surface, place it in neutral and see how easy it is to push..You should be able to move it with just one hand...I had a car once where the handbrake had a habit of overadjusting all the time...This resulted in the handbrake never releasing properly...Skyline handbrakes (drum inside disc) aren't known for this but you never know..

Also check the position of the crank angle sensor...If everything is stock, the CAS should be roughly centred in the adjustment...If it is retarded (rotated clockwise) fuel economy will suffer...

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