R33 Gtr Problems - Running Rich? Drinking Too Much Fuel

[drgtr7]

Goodafternoon fellas',

Im having some issues with my car, before i go on, i would just like to say that my car standard apart from:

- Front pipes

- Hi-flo metal cat

- Apexi cat back

- K&N Pods apexi intake

Now my problem is, my car isn't lacking power, but it just chews fuel and i mean $50 petrol and im lucky to get 200kms if i drive like a granny possibly 250km. Now something can't be right? Is this just a normal occurance with GTRs? I've read on here that people get way better fuel economy. The car is due for service in another 500kms so looking at changing sparkies, oil, oil filter ect.

I've done my search, but nothing really hits the nail on head with my case. When the car got here, it was 100% stock except for the Apexi catback, Stock airbox front pipes ect ect.

Really would appreciate any feedback advice, and or whatever. Seeing as the car is my daily for the meanwhile its smashing me sick in the wallet.

Thanks guys.

[Dose Pipe Sutututu]

If the O2s are the same ones from factory I would change them, then give the AFMs a good clean too. While you're at it, tighten up all your FMIC piping hoses, etc.

[Pal]

im getting 15l/100 on mine. have changed the o2 sensors as well. i do alot of around town driving though

[drgtr7]

im getting 15l/100 on mine. have changed the o2 sensors as well. i do alot of around town driving though

Thats decent, mine works out to be 16.5l/100. Thats mixed driving; freeway and in and out of the suburbs.

[3LGODZILA]

has the fuel economy gotten worse ? or have u just got the car and expected it to be better?

gtr's CHEW the fuel dude

[pistol-pete]

$50 of 98 isnt that much these days, 200km from that isnt that bad.

i managed to get under 300km out of a full tank once.

get a new ecu for it (nistune, pfc etc...) and youll be able to tune it for much better economy

[drgtr7]

has the fuel economy gotten worse ? or have u just got the car and expected it to be better?

gtr's CHEW the fuel dude

Hrmm i dunno bro, I mean i've owned that car since last year August. I never remembered it being this bad. I mean it was thirsty but now its just stupid. It is kinda standard after all, expected it would be better :S?

I guess what im trying to ask is there anything i can do to, increase fuel economy?

[drgtr7]

$50 of 98 isnt that much these days, 200km from that isnt that bad.

i managed to get under 300km out of a full tank once.

Lol, but is it normal to say go from 4th to 2nd to say overtake then stretch the gear a bit, and once your in 5th cruisng you look at the petrol needle and see that it has drop? haha

[pistol-pete]

I guess what im trying to ask is there anything i can do to, increase fuel economy?

replace your o2 sensors, get a nistune and it will improve

[Pal]

i got a power fc, but hasn't been tuned in a long time. going in next month so hopefully it will get better. although i did get it down to 13 l/100 once

[mad082]

plenty of factors to consider when looking at fuel economy. generally only use others economy as a rough guide as there are so many variables. here's a list of things to consider:

- do you let the car idle to warm up? (an idling car will use a few litres per hour)

- how long does the car take to warm up? (if more than a few mins when driving then get a new thermostat)

- how much time do you spend sitting in traffic?

- how hilly is it where you drive?

- how often do you go into positive boost?

- how much throttle do you apply at low rpm? (fuel economy has little to do with revs but throttle percentage. you can rev it out to 5000rpm using light throttle and get better economy than someone who only revs to 3000rpm but floors it to get there)

you can check a few things to help get better economy. o2 sensors are a good place to start. also worth jacking the car up and spinning the wheels to make sure you don't have a sticking brake caliper (or hand brake) or damaged wheel bearing.

[drgtr7]

plenty of factors to consider when looking at fuel economy. generally only use others economy as a rough guide as there are so many variables. here's a list of things to consider:

- do you let the car idle to warm up? a few mins is enough (an idling car will use a few litres per hour)

- how long does the car take to warm up? warm up meaning halfway mark?

- how much time do you spend sitting in traffic? Not alot

- how hilly is it where you drive? Not at all

- how often do you go into positive boost? A fair bit, just normal driving

- how much throttle do you apply at low rpm? (fuel economy has little to do with revs but throttle percentage. you can rev it out to 5000rpm using light throttle and get better economy than someone who only revs to 3000rpm but floors it to get there) Quite alot, i normally am to lazy to drop a gear sometimes, so i just give it more gas

you can check a few things to help get better economy. o2 sensors are a good place to start. also worth jacking the car up and spinning the wheels to make sure you don't have a sticking brake caliper (or hand brake) or damaged wheel bearing.

I'll be getting the o2 sensors and checking all these things in the coming weeks. Thanks mayn.

[Dose Pipe Sutututu]

Also, I would see if the engine's thermostat is working. It might be seized and always opened. The ECU will dump in more fuel when the water temp is low, does your car's water take forever to warm up?

[jiffo]

As Marc said, driving habits are the first thing to address if you want to see better fuel usage.

As for oxygen sensors, again, they do absolutely NOTHING if your driving style is heavy.

Do some Googling re-oxygen sensors and you'll see there are many factors that must be satisfied before the ecu will even go to closed loop.

For the majority of time you're running in open loop (no feedback) and the oxygen sensor input is ignored.

Biggest joke out, replacing oxygen sensors and then driving pedal to the metal.

As your problem is somewhat recent, my first look would be coolant temp sensor.

But don't just replace stuff willy-nilly, pay the $$$ to get everything professionally checked.

[drgtr7]

Also, I would see if the engine's thermostat is working. It might be seized and always opened. The ECU will dump in more fuel when the water temp is low, does your car's water take forever to warm up?

Come to think of it not really, about 4-5 minutes before the needle moves. This is in 5 degree weather (Melbourne)

[drgtr7]

Okay hold on a sec, how long does it take for your cars to hit the half way mark, and how long does it take for the needle to move? This could possibly be my issue?

[Dose Pipe Sutututu]

Probably around 5 to 8 minutes of doodling about before it reaches 80 degrees as per the PFC hand controller

[mad082]

I'll be getting the o2 sensors and checking all these things in the coming weeks. Thanks mayn.

boost is the enemy of fuel economy. by the sounds of it o2 sensors won't help your economy much as your driving style is causing your poor economy.

[EAT26]

I personally get about 400-450ks to a tank on low boost (14psi/340rwhp) in a mix between driving 80ks a day a least with mixture of country back roads and highway driving nice and casually... but If i bump the boost up to highboost(21.5psi/467rwhp) it will chew very badly about 200-250 per tank.

So about 12.5/100 on a very very good run still not as thirsty as my mates Ve ss his worse fuel consumption was about 23/100 stock :S

I have changed the following

Power-Fc

2860-5s

Tomei Dumps

100 Cell Cat

Nismo 600cc Injectors

Nismo Fuel Reg

Nismo Fuel Pump

HKS Hard piping for intercooler

Cooling-pro Front Mount.

I am still running the stock AFMs but clean them regularly!

Clean your AFMs and Airfilter, Change your plugs etc.... My question is have you recently changed the oil brand/weight lately? I only ask as I changed my oil from 0-40w Castrol edge to Royal Purple 3-35w and I noticed a mass drop in response and reliability... so I changed the oil out a week later I also could hear the oil slapping on cold start.

Edited July 3, 2011 by EAT26

[drgtr7]

I personally get about 400-450ks to a tank on low boost (14psi/340rwhp) in a mix between driving 80ks a day a least with mixture of country back roads and highway driving nice and casually... but If i bump the boost up to highboost(21.5psi/467rwhp) it will chew very badly about 200-250 per tank.

So about 12.5/100 on a very very good run still not as thirsty as my mates Ve ss his worse fuel consumption was about 23/100 stock :S

I have changed the following

Power-Fc

2860-5s

Tomei Dumps

100 Cell Cat

Nismo 600cc Injectors

Nismo Fuel Reg

Nismo Fuel Pump

HKS Hard piping for intercooler

Cooling-pro Front Mount.

I am still running the stock AFMs but clean them regularly!

Clean your AFMs and Airfilter, Change your plugs etc.... My question is have you recently changed the oil brand/weight lately? I only ask as I changed my oil from 0-40w Castrol edge to Royal Purple 3-35w and I noticed a mass drop in response and reliability... so I changed the oil out a week later I also could hear the oil slapping on cold start.

Its going for a service soon, so hoping to change oils. Ive been using Motul 8100 5-40w fully sen since i started driving it on the road. So maybe a different oil could help? What do you guys reccomend?

Im also going to buy an ECUtalk cable of ebay, sus out shit some more, get a better idea of whats happening.

BTW, thats great fuel economy dude