Bad consumption

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wildfaye
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Post by wildfaye »

Ok, guys, back with another query before i go to the workshop.

This current bad consumption i have is based on city and highway driving with speeds not exceeding 110km/h.

I have been on the Malaysian highways and gotten the following consumption figures. 130-140km/h constant for 2-3hrs. I manage to get 12km/l.

Would it still be the O2 sensor??
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wildfaye
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Post by wildfaye »

Ok, its been awhile, schedules done meet hence I only managed to get it checked yesterday.

Went to my garage and they plugged in the Mit Mut 2 diagnostic equipment into the socket under the dash.

I must say,its a pretty cool looking piece of 'EXTRA sized' PDA with a touch screen that comes in a briefcase.

BUT, no errors codes was found with regards to the bad fuel consumption or any other issues and the car is healthy and running fine.

The manager informed me that prior to returning the car to me after the service, the MUT 2 was used and no errors were detected too.

The reduction in fuel consumption baffles him too.

Any suggestions anyone?

Thanx!
Sam
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Post by thecook »

i get pretty bad feul economy too, maybe about 420km on a full tank, 500km on a full tank if i drive slow, dont go hard, and have the orange petrol pump light on for a while too, etc..

i think its just the engine getting more worn out, getting higher km's on it etc
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RichardH
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Post by RichardH »

Some random thoughts on fuel consumption...

- More stuff in the car? Like, big new subwoofer enclosure? :)

- Lower tyre pressures than before? Using higher pressures really does improve fuel economy.

- Using the aircon more lately?

- Dirty air filter?


You could try running some good quality injector cleaner through the system...

Good luck!

- Rich
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MADFTO
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Post by MADFTO »

OH one other thing. Recommended tyre pressures aren't always the best for fuel economy or longevity, it's there usually for comfort.

Try inflating your tyres up to 36-40psi depending on how harsh a ride you can cope with =)

I was running 50psi for a while, taking corners never felt so good =) heheheh but anyways, I'd say 40psi for the street =)
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wildfaye
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Post by wildfaye »

Hi Smorison,

Had my car checked for error codes, but none came up.

As u mentioned before, a knackered O2 sensor would not be detected, is that rite?

what you do suggest? Should I down $300 to get the sensor changed?

Sam
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smorison
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Post by smorison »

a decent mechanic will be able to check out your O2 sensor and let you know if its the issue. it also would probably be worth doing a fuel / air ratio test (which can be done on a dyno) to see if there are other problems - if its not your O2 sensor.
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Post by G1 »

i get roughly 500km when the warning light comes on.

mainly city driving (non highway)

this is with regular hard driving too.

anyone getting less should have reason to worry and look into it
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wildfaye
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Post by wildfaye »

Hi all, just an update.

I used to be using esso/mobil 98 octance petrol.
Average of 2 fills can yield me 9km/l.

Weirdly enuff, of 2 fill ups, when i get 8.7-8.8 this week, the next week i will definately get 9.2-9.3!

Weird?! isnt it?

Now, petrol price have sky rocketed! Damn those oil cartels!

We are paying SGD $1.488 per litre of 98 petrol!

I have since downgraded to 95 @ $1.405 per litre.

I do not feel any noticable difference in performance as yet(1st fill up last week), my 1st fill yielded my 9.3km/l.

I am hoping to get a more satisfactory result at the next fill next at the end of this week.

As of now, my fuel filter and fuel pump filter has not been changed
Due in on the 5 Jun with a oil change.

Let you guys know what are the results again.

Cheers!
Sam
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rxboy
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Post by rxboy »

errrr..... I'm getting about 8km/L too. I thought this was normal. I'll typically have about 420km on the trip meter when the fuel light comes on. But I don't do any freeway travel at all, just many tiny trips around my area. That's why I thought my fuel economy was so bad. Plus it used to be worse when I was using regular ULP. When I do a lot of freeway driving, the economy improves a whole lot as expected.

So is my FTO in the same boat as Wildfaye's or do most people get similar figures?

PS: I don't have any heavy equipment. I don't have any passengers and I rarely ever use air con or heating. My tyre pressures are set at 38psi all around.
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Post by Supplanter »

I am getting around 9km/l, 4 speed tip.
I use aircon once or twice a week, and enjoy a little bit of MIVEC mischief now and again.

Using BP Ultimate as part of my fuel efficiency experiment (more on this when I get more results :wink: ).
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mrx
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Post by mrx »

Getting an easy 550-600km to a tank, and have not spotted the fuel light yet. Of course, I am not doing city driving (Newcastle traffic nothing like that) with regular highway trips. Do indulge in some MIVEC pleasures when i get the chance.

It is funny though. Some days I think I will just control my urge and stay at "normal" rpm's for a few days and see how the economy goes. Well.....that lasts for about 10 minutes!
FTOluv
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Post by FTOluv »

i get 460km with a full tank and thats with the fuel light on. i reckon why mine is slightly more is because i have three 12" subs in the boot in a huge custom enclosure :P
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wildfaye
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what RPM in top gear @ 100kmh?

Post by wildfaye »

Hi all, just wanna check your rpm in your top gear at 100kmh?

There are 3 versions, 4AT, 5 AT and 5 MT.

Mine is the 5AT and in 5th gear at 100kmh is 2500rpm.

Can those peeps with the other 2 versions do a quick update on this please.

Thanks!
G1
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Post by G1 »

my 5MT is on 3000 rpm or just above when doing 100kph from memory
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payaya
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Post by payaya »

around 2900-2950 RPM at 100km/h. This is on a 4AT.

i can get low 500's but thats with the petrol needle 2-3mm on the left side of the empty line :)
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Post by Jono »

hmmmm i used to get about 560 kms per tank.. recently been getting 460 480 per tank... could this be because of Fuel filter?

Ive done some mods recently, cat back and UAS CAI. Ive also Reset the ECU after the mods.

Jono
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wildfaye
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Post by wildfaye »

Wow...what a diff btw the diff gearboxes
5AT 100kmh 5th gear 2500rpm
4AT 100kmh 4th gear 3000rpm
5MT 100kmh 5th gear 3000rpm

i was expecting lower rpm on the 5MT!

nevertheless, the lower rpm in 5th on the 5AT will definitely contribute to better fuel economy.

as i have indicated in my previous posts, i have switched to 95 petrol recently due to increases in petrol prices, and have noted the following results:

no noticable diff in performance
better fuel economy! I used to get 8.5-9km/l now, i get an average of 9.5km/l

of cos this is definitely not as good at when i was using 98 petrol when the car was new, however, the things to note are:
more cars on the road, more start stop traffic, aircon not as efficent as when new! so i guess it'll stick to 95 from now on!

(i guess i would have gotten better fuel economy if i started out with the 95 brand new and saved more money in the long run! blast those oil companies! :evil: )
Jono
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Post by Jono »

Hey wildfaye..

im visiting Singapore in june july, i should come check out your fto sometime.. :)

Jono
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wildfaye
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Post by wildfaye »

Another update on the bad comsumption...a long awaited 1...

I changes to the new oxy sensor at SGD300 a while ago, but now the fuel economy is back to 8.8km/l :?

I was wondering is i actually wasted 300 bucks on a sensor that wasn'r spoiled at all? ouch...pocket hurts...

Could it be some other thing malfunctioning? no MUT2 errors...

Could it be the catalytic converter has busted? :(
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