R33 Bad Fuel Economy

[rich flavour]

When you said changed not long ago, was it changed with a brand new unit ? or a second hand one?

These sensors are only worth 40,000km's.

If its older then that or your unsure how old it is... Change it!

seconf hand one.. should i get a new one form nissan???

[delljit]

http://www.kudosmotorsports.com/catalog/pr.../products_id/42

only $77 if you're a member of sau forum

[siddr20]

I recently changed my 02 sensor (like 3 days ago)

Bought it from kudos..

Anyways i have noticed a big improvment in fuel economy. Also changed my plugs to the right heat range (which does matter)..

So with both these done, im getting much more KMS than before.

[SiR_RB]

i just changed my dump/front pipe and when i pulled my oxy sensor off it looked very clean, no carbon build up on the bit that goes in the exhuast. this thursday i'l be going for a long drive up the coast for the weekend.

my question is, can i pull it out, spray carby cleaner on it, and use the air compressor to blow it dry ?

as i wont have time to change it till next week, and i'l be using the car alot this long weekend, will this help economy abit?

cheers

[Guilt-Toy]

YES

Well doesnt have to be from nissan, just new and working CORRECTLY

seconf hand one.. should i get a new one form nissan???

Edited March 18, 2008 by Guilt-Toy

[bombastic]

I get 10.5L/100km (~ 600km/tank). Urban driving mostly 60km/h zones. And I open it up a fair bit.

Mods: R34 SMIC, full exhaust, 10psi.

Strange so many seem to be getting only 400km/tank?

[JustinP]

Also don't buy cheap shitty O2 sensors. I was getting shitty fuel consumption ages ago and brought one off eBay that was compatible for about $30. It did work (kinda) according to the PFC, but fuel economy didn't improve. Then after a few months it stopped working all together. I recently brought a geniune Nissan one now I'm getting 50-70 more k's per tank. Still only getting about 340-350 with mostly city driving. I might take it somewhere else to get the tune touched up to try and improve economy some more.

[smidy]

guys just been through this recently, different approach but may have similar dramas. had a few small cracks in the intercooler bars on the join where they meet the entry/exit chambers( standard intercooler on r33 gtst ). was lucky to get 350km/tank not squirtin it too much, then got another off ebay in good nik whacked it in an "bob's ya uncle" bonus km's around 400+/tank (haven't had the chance to calculate 100% but you know when theres a difference).

was also expeirencing bad flat spots in acceleration climb through gears if you punched it to hard, b4 noticing the intercooler problem.

reason i highlight these points is check all things for air leaks to be on the safe side before $$$ expenditures. slightest air leak holes create big dfferences.

hope this may shed some light or kms on you fuel drainers!

i have also changed the o2 sensor and plugs to make sure. next thing to fine tune it is a power fc when the cash is handy !!!

[KJS]

Hi I just got a used R33 Sedan Auto GTS-T from a dealer.

the fuel consumption I think is ridiculous after reading what you guys had posted.

basically it has no mod under bonnet except a pod filter (without taking suspension, wheels, turbo timer those into account)

the first tank of fuel it used could only produce 250kms

now after spending around $150 in fuel, it can only reach 450kms (since I bought the car a week ago).

what is strange about the car is, the vacuum is blocked.

now my friend connected the vacuum to somewhere near the sensor near the pod.

and reset the ECU by unplugging the battery and plug it back.

I wonder if the fuel efficiency still has no improvement, what apparoach should I follow next?

should I.....do like what was posted earlier Aftermarket ECU + remap + piggyback?

or first try changing O2 sensor?

what's the next step.

anyone knows approximately how much would those cost?

[DaGr81]

i used to only get 260 - 280km per tank aswell but the things i did were, change the 02 sensor, change the BOV to stock, cleaned afm with contact cleaner and also cleaned my water sensor plug.

my car has the following mods (also remember that my car started out life as a non turbo as a result i have more compression than most also as a result of the compression i have a shitload more torque than others with 200rwkw:)!) whether or not this helps with fuel economy or not but eh

pfc

intercooler

ebc

walbro fuel pump

nismo regulator

full trust turbo back + xforce cat

trust pod and airbox

and a 52mm alloy radiator

i get 450km per 50L fill up (where is my last 15L? fksake) i found that changing the apexi twin chamber BOV to standard i can get 100km from 9L which is quite good highway driving and shit loads of boosting whereas before id get 12 or 13...remember every litre counts

[KJS]

so does that mean by having a better cooling system will also affect the fuel usage?

such as radiator and intercooler

the bov which i am having is stock

and water sensor plug, afm also related to fuel usage?

seems like the PFC which everyone has, works good in this.

did you change everything at once? or you change things one by one and observe the consumption? (could you list which one is the most worth changing in the favourable order)

[nuclear_skyline]

Three things kill fuel economy:

1. Crapped out O2 sensor. Been covered here heaps....

2. Leaks in lines... Check and re-new all vaccum lines, and other perished lines in the engine bay.

3. Crappy tune.

Check 1, if its ok, check 2, then check 3....

I get over 500kms a tank with full zorst, FMIC, 12psi and stock computer.... Well, should be better now I have the EMU installed

[donkey]

sorry if i missed this, but if you get a new O2 sensor, would it affect the tune (power fc), or will the computer compensate........cheers robbie

[SiR_RB]

my car has full 3" turbo back exhaust 3" high flow cat, front mount intercooler, pod with cold air intake and grounded boost control solonoid running 10psi.

i get 420 - 450kms per tank on 98 octane city driving with the odd squirt here and there.....and that is without the fuel light coming on, i never let my fuel get that low.

high way driving, and city driving, well over 550kms.

like others hav said, change ur o2 sensor, plugs, and maybe try running 9psi to stop ur ecu running rich

goodluck !

[R34GTFOUR]

i was driving aorund witht he fuel light on for a a while then was sitting in line at the servo so it was as good as dry as a bone

that fuel light can last upto 100km you know that right?

the best way to measure fuel economy is to do it as gtst said, or if you want to do it your way, drive around till it starts cutting out around corners (thats when its really low haha)

[KJS]

okay I will try changing the O2 sensor.

and also I will check whether there is leak along fuel line but I doubt it unless the dealer is really that mean

then I will try to check those vacuum.

if I have extra money maybe an Apexi Power FC like everyone does (isn't it expensive??? haha)

but thanks for those posters above.

[nuclear_skyline]

okay I will try changing the O2 sensor.

and also I will check whether there is leak along fuel line but I doubt it unless the dealer is really that mean

then I will try to check those vacuum.

if I have extra money maybe an Apexi Power FC like everyone does (isn't it expensive??? haha)

but thanks for those posters above.

Dude your fuel bill is way more expensive in the short run for you... Check all the mechanicals, then if still not getting any reasonable increases in economy get a computer. Apexi SAFC are cheap, Emanage are more expensive and heaps better, and PFC are great but really getting expensive.

[simpletool]

AFter changing your O2 sensor get a REMAP....search the forums. 2 guys do them to stock R33 ECUs with their own wideband. Cost < $500.

[KJS]

I changed my O2 sensor, then I bought those liquid to mix with fuel which helps in cleaning the fuel injector (I am not sure whether it works). I also changed the oil filter and engine oil.

the thing that concerns me is after changing the oxygen sensor, the mechanic used a scanner and plug in the plug under the driver's steering. He said the scanner detected no error code so the O2 sensor might not be the cause (unless it is running but getting lazy). He also said the sound is good and sound like no vacuum leak. He said the scanner cannot detect fuel injector so he sid could be that problem, or catalytic is blocked? then he told me to drive and sees how it goes.

my friend also used a "start ya" to check for vacuum leak and apparently no

the car goes with smooth boost too

now my first slot is just slightly more than 100kms.

do you guys reckon that is alright for an Automatic RB25DET?

do you think I should clean the AFM with Carbie Cleaner (I come across this method many times in this forum)

do you think I should change plug?

also the pod filter sound is quite loud... is it supposed to be like that?

I really seldom drive fast and is everything is stock except the aftermarket 3" exhaust (I didn't know it is aftermarket till my friend told me) and the pod filter.

could you guys list out more things before getting remap? because I doubt i have the money to get aftermarket ECU now, lol

eg what else to check...

[adis]

I just bought a lightly modified gts-t, 33, and have been doing a bit of fuel tests. Best i got was 10.5L/100Kms, on freeway. Worst i got was 13.2L, that was around city with fair bit of boosting.

Id say around 11.6L per 100Kms in on average my car fuel usage.

Mods i have is cooler, pod and cat back.