Help! :( Bad Fuel Economy ..

[HEKT1K]

hey guys

im new to skyline ownership and these forums.. (just traded up from an old commonwhore.. best decision i ever made!)

ive noticed that with sensible driving im only getting about 330kms per tank, and there are quite a few black powdery flecks on the rear of the car, but nowhere else...

is it possible that a rich air/fuel ratio could be causing these two problems?

any help / advice much appreciated!

thanks

Ric

[__PhaseShiftDown]

Does it come with aftermarket ECU? My old 180sx does that, because the pfc tune was too rich.

My 32GTR, stock with just a exhaust makes 400km a tank, around 15L/100km. Thats with mixed highway and street driving.

Check/Change/Clean your air filter, fuel filter, O2 sensor, AFM and you should see economy improve slightly.

Edited June 14, 2008 by __PhaseShiftDown

[HEKT1K]

nah dude it's pretty much dead stock, just turbo back exhaust. ill have a look, but like i said im new to skylines so i might just be imagining things! haha cheers for the tip

[Damit]

hehe my line gets about 200 kms and thats with only a bit of boosting and its a stock 33s2 with only a catback and i know mine is running rich just to lazy to get a new 02 sensor because i know my AFM is good

actually thinking about it would be cheaper to put it in to a workshop to get replaced than to keep paying for more fuel

[mid life crisis]

series 1 r33 fmic /pod filter 9 pound boost /auto trans and i can get 400ks+ plus from a tank with no problem at all

[HEKT1K]

so it IS the o2 sensor then? i should get that looked at.. especially with petrol prices these days!

[__PhaseShiftDown]

If you only just got the car and the place you bought it from haven't serviced it before they sold it to you. Defitnitly change the oil, oil filter, fuel filter, air filter. Clean the AFM using non-lubricating contact cleaner (buy from jaycar) and also replace your O2 sensor.

When I got my 32, it came with new air filter and oil and oil filter...etc. But they didn't change the fuel filter, after I replaced it, the car feels a lot more responsive and willing, the fuel economy improved a bit as well. So defitnitly replace the fuel filter as well.

[snappy_]

hey guys

im new to skyline ownership and these forums.. (just traded up from an old commonwhore.. best decision i ever made!)

ive noticed that with sensible driving im only getting about 330kms per tank, and there are quite a few black powdery flecks on the rear of the car, but nowhere else...

is it possible that a rich air/fuel ratio could be causing these two problems?

any help / advice much appreciated!

thanks

Ric

Because of this, i'm glad you saw the light.

[HEKT1K]

snappy: lol i was never in denial about how pov my commodore was, i inherited it when my mum traded 'up' to another newer commodore, so i was just kinda stuck with it. i always knew that jap cars were much much better haha give me a little credit

ps. drove the commodore (trying to get rwc to sell it atm) the other day after a month in the 'line, damn thing felt like a bus!! lol

[Amec]

causes of poor fuel economy include:

- dead knock sensor

- dead O2 sensor

- faulty engine coolant temp sensor

have your ECU checked for error codes.

[Sandeep]

well well well... i told you to get a zed Ric...

Man I've got nissan datascan, shoot me a pm and we'll run your car on it and i can check out your o2's and everything else.... I finish up exams next week. I was gonna do a write up on fuel economy problems, but I'm not 100% familiar with skylines so I'll use your car a guinea pig.

We'll go cruising soon.

p.s. please tell me you bought a manual...

edit: just saw that you have an SII, not 100% sure if my laptop will plug into an S2 33, I know it plugs into SI. I'll find out anyway

[Amec]

well well well... i told you to get a zed Ric...

Man I've got nissan datascan, shoot me a pm and we'll run your car on it and i can check out your o2's and everything else.... I finish up exams next week. I was gonna do a write up on fuel economy problems, but I'm not 100% familiar with skylines so I'll use your car a guinea pig.

We'll go cruising soon.

p.s. please tell me you bought a manual...

he he when you can fix zeds you can fix anything Nissan

[HEKT1K]

Sandeep should i be trusting your laptops and gizmos and shit around my new baby? hmmm... the idea of my car being a 'guinea pig' isn't exactly reassuring haha

[Sandeep]

well my laptop won't plug into your ecu, but you should still be able to do an ecu diagnostic using the flashing light on your ecu. there should be a tech article somewhere on here. otherwise you can test your o2 using a multimeter. you want your engine to be nice and warm, the voltage from the o2 sensor should be cycling 5-10 times every 10 seconds at 2000rpm when everything is at operating temp.

other things to check would be the coolant temp sender (should be on the top coolant pipe). Sometimes the connector gets corroded and it interferes with the temp signal. when this happens your ecu may think your car is always running cold and it will richen up the fuel mix. also if your thermostat is stuck open your car will run too cold and your fuel economy will be shit.

don't worry, i won't wreck your baby. I've pretty much had to redo most of the stuff on my car. when i got it i was getting about 200km/tank, had to fix up detonation sensor wiring, cleaned coolant temp sensor, replaced both o2's, fixed up all my vacuum leaks, replaced all the fuel lines, cleaned afm, cleaned throttle bodys, replaced blocked cats, new spark plugs, series 2 ptu, replaced air filter. I now get about 450km to a tank of normal driving and i can get 600km on the highway. Next week i'm pulling the plenum off and getting the injectors cleaned and flow tested and i'll replace all the o-rings and run new vacuum because that's all i have left to do.

[teng]

On average my r33 S2 will travel ~200km when the fuel gauge reaches 1/2. Engine internals stock. Dunno how many L/Km that is. lol

Edited June 24, 2008 by teng