Bad Fuel Economy?

[Canadian 32]

So Since I got my car I have only been getting about 250-300 km to a tank. Which is really bad and I cant figure out why, since I am shifting around 3500rpm and "took the lead out of my foot". My car doesn't have any engine upgrades beside splitfires, plugs, ssqv, intake. And yes I checked there is not a hole in the tank. Although the car does have a mines tuned ecu in it; so I am thinking that this may be what is causing this bad fuel economy since the car does seem to be running 8-9psi as well. I am in the middle of replacing a bunch of parts, a couple being a power fc and a new fuel pump. so I will have my fingers crossed that that might fix the problem. If anyone has any idea could you please post something.

thank you very much for your time.

[CEF11E]

replace the o2 sensor.

cheers

[WogsRus]

Well ok so here are a few contributing factor.

O2 sensor is a bad one, i changed mine got an extra 50-80 kilometers in town, more on the higway

ECU temp sensor, if that is dead, then you will be running enritched maps. See if it is within spec, there is a post on this already.

A small spark plug gap is another one, i have to run 0.6mm now and it sux on fuel, new coils with a decent gap will increasy fuel economy drasticly.

Vacume leaks, when your car is idleing hot, the vac should be about 17mmHg, see if you have Vacume leaks.

Exhaust leaks will also suck through juce, so check for those.

Apart form that, the stock ecu is dam ritch, and if you get a tuned ecu or SAFC II to take some of the fuel out, you will get more power, better fuel ecconomy and less backfire.

[R31Nismoid]

http://www.skylinesaustralia.com/forums/in...showtopic=43095

Link came from the sticky thread

[mad082]

and you are running an atmo bov which will ever so slightly decrease fuel economy.

also try cleaning your afm. i am getting about 10% better economy after doing mine.

[R33S2]

Mines ECU tuned to run on 100ron? What ron does canada have?

[Canadian 32]

Thanks a ton for all the replies. I took a look at the 02 and I am thinking it's on its way out so I am just going to replace it I think.

[GTR-Dad]

Mines ECU tuned to run on 100ron? What ron does canada have?

Canadian octane ratings are PON, which is (MON+RON)/2. We can get 91 PON anywhere and 94 in some places. 91-94 PON is probably comparable to 96-98 RON, give or take.

JDM Mines tuned ECUs are not tuned for this fuel, but the OEM ignition retard smarts are still there and so protect us from ourselves.

Dan

[gt-t_r34]

wogsrus makes good suggestions that ecu could be your trouble.. what about the timing could be advanced too much for even the jap fuel... but wouldnt it knock?

hmmm wierd