Fuel Consumption.

[dyken]

hey guys i got an r33 gts25 rb25de. usually to a full tank ide get an easy 450-500km.

pretty much used the whole tank today its sitting on the bottom bar and ive only done 299km.

any ideas as what could cause such bad fuel economy??

ive checked exhaust for leaks but there isnt any. the car has had no loss of power so ??? i dunno what it could be.

and yes ive tried the search but couldnt find anything

[MBS206]

Changed your driving style today? Sprited driving?

Could also be dirty AFM, bad oxygen sensor.

Probably a few others things I can't think of, but I'd be replacing the O2 sensor, and cleaning AFM straight away.

[Eug]

and yes ive tried the search but couldnt find anything

really?

http://www.skylinesaustralia.com/forums/Pr...uel+consumption

http://www.skylinesaustralia.com/forums/o2...uel+consumption

o2 sensor, service the car, maintenance, etc.

troubleshoot what you've changed recently. ambient temp can also have an effect.

[dori34]

i get around 400 sometimes 450 so im happy with it.

[dyken]

thanks eug for that.

my driving has not changed, i havent been driving it hard at all.

ill clean the afm. and check the o2 sensors. it shouldnt be to hard to change the o2 sensor myself shouldnt it?

and yes im useless with the search..

[ArBe20]

it shouldnt be to hard to change the o2 sensor myself shouldnt it?

Nope, very easy

[Charles89]

hmmm..would any1 be able to post a pic of the o2 sensor?...that'd help alot, since im planning to change mine myself.

thanks guys

[MissR34]

my o2 has decided to die on me plus my rocker cover gaskets are leaking................

[ArBe20]

It's a little plug that sticks into ur exhaust in the engine bay.

Here is some of random cars.

http://neksiwel.20m.com/images/o2_sensor.jpg

http://www.slantsix.org/articles/bryan_lon...ygen-sensor.jpg

[Charles89]

i think i found mine...its got a bit of surface rust on it, does that mean its old and i need a new one?

[inthisglass]

if you do a search there is a cazillion topics on o2 sensors

basically they are meant to be changed every 40 thousand kms so its a good idea to get a new one

when i got a new one about 5 thousand kms ago my fuel went from 450 kms to a tank to about 530 kms a tank so its well worth it.

[R334door]

didnt forget to screw your fuel cap back in did ya? very basic but i have seen it before.

[Sandeep]

first thing is to check for fuel leaks, a clamp may have come loose somewhere in the engine bay so just check them to be safe. also check your coolant temperature sender for surface corrosion on the connector... if the ecu doesn't get a good signal from the coolant temp sender it may think the car is running cold and will richen up the AFR's. you can clean the CTS with a nail file, just need to remove any surface corrosion so that the sensor and loom connector have nice clean metal.

if O2 sensors and CTS checks out, check your fuel pressure regulator and also do an intake pressure test to see if you've got any vacuum leaks.

also try and get your car on consult or datascan to check for error codes.

[Modena]

Funny... I have a stock R33 GTS-T and I get 450-480 KMs pretty much all the time to a tank.

There seems to be little diff between fuel eco with NA and turbo skylines (not including the modded turbos)

[dori34]

if there was a fuel leak ^ then you would definately smell it.

[Charles89]

i just filled up yesterday, and it drinks 10.8L per 100km, is that good?

[inthisglass]

i'd be happy with that

you wont get any better from a skyline

[TokyoTaxi]

After you've gone through all that, get your injectors taken out and properly cleaned and inspected ( condition & spray pattern ). Chances are, if you've done over 100,000Km the spray pattern and operation of your injectors will be less than optimal.

Just my 2 cents......

[dyken]

no fuel elaks from any clamps anything, will be changing o2 sensor this weekend and cleaning afm. hopefully it will be fine after that

[Sandeep]

have you tested your o2's? you can do it using a voltmeter or using consult/datascan. you just need to make sure they're nice and responsive and that the voltage output should sweep from low to high about once a second. datascan or consult is easiest coz it will just display the voltage output for you. just make sure your car is at operating temp and you'll need to rev to about 2000rpm when you're measuring the voltages.