MAF sensor vs fuel consumption?

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MAF sensor vs fuel consumption?

Postby Tagged » Fri Sep 20, 2013 9:20 pm

The Altezza im currently driving has been doing 400k per tank on Z95.
Person I bought from told me while he had it, which was two years ago (the car has been sitting there for two years with someone starting it once every now and then), was doing 500k per tank.

So I thought I'll clean the MAF sensor.
Went from this:
https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn2/1185302_3460808696910_1094054439_n.jpg

to this:
https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-prn2/1237081_3460808776912_1803736129_n.jpg

Now, im not really seeing too much difference.... I think I read somewhere that MAF sensor clean should be paired with ECU reset?? I cant find where this came from anymore but does any one know anything related to this matter?
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Postby Bling » Fri Sep 20, 2013 9:32 pm

Is your driving open road or short trips in town? How many litres do you put in when you fill up? How hard do you drive it? Manual or auto?

People claim some pretty good mileage when selling cars, I believe none of it.
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Postby KinLoud » Fri Sep 20, 2013 11:16 pm

Biggest influence on fuel consumption is driving technique
Foot flat around pukekohe might get you 20 litres per 100km!
75 kph driving from Bombay to Orewa (don't do this at rush hour) might get 6 litres per 100km.

Driving my old car (1993 Marino, 20V 4age) carefully could get 700km to a tank (about 47litres to fill from dead empty) with a mix of Auckland city driving and cruising from Auckland and Hamilton.

Full throttle accelerating is fine as long as you keep revs low (shift by 3000rpm).
Keep speed low(ish) - try 95kph on the open road
Don't pass cars - just cruise
Coast a bit down hills
Put on cruisey music - rock just makes me drive fast!
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Postby Crucible » Sat Sep 21, 2013 1:08 am

A dirty maf actually creates a lean condition. ecu fuel trim reacts to a lean O2 signal and increases trim numbers to bring your O2 back to stoich.

So now your ecu is injecting more fuel to keep O2 in the right range.

when you clean the sensor wires the O2 now goes way rich at that load point so now fuel trim takes fuel away to bring back to stoich. The fuel trims now have to relearn and eventually bring correction back to 0%.

Driving the car will in time bring trims back to normal. :)
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Postby Tagged » Sat Sep 21, 2013 1:18 am

uh yes I missed out a lot of info here...

I drove very conservative and all driving is around town. 50L was put in when I filled up 20kms after the light came on. It is an auto (unfortunately).

prob should have mentioned that I bought it from a close friend so 90% chance he should be telling me the truth haha... hopefully lol
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Postby Tagged » Sat Sep 21, 2013 1:19 am

Crucible wrote:A dirty maf actually creates a lean condition. ecu fuel trim reacts to a lean O2 signal and increases trim numbers to bring your O2 back to stoich.

So now your ecu is injecting more fuel to keep O2 in the right range.

when you clean the sensor wires the O2 now goes way rich at that load point so now fuel trim takes fuel away to bring back to stoich. The fuel trims now have to relearn and eventually bring correction back to 0%.

Driving the car will in time bring trims back to normal. :)


oh I see! so I guess I'll have to wait a bit before seeing any changes. Assuming there are changes to be made that is...
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Postby Bling » Sat Sep 21, 2013 8:28 am

12L / 100km around town in a 2L auto doesn't seem THAT bad.
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Postby molex » Mon Sep 23, 2013 1:57 pm

Old BMW E39 540 would do 10.8L/100KM around auckland in traffic, so 12L in a 2 litre sounds pretty terrible. My 3.5L Blades worst ever tank was 440KM's from 50L with average speed of 12KM/h interspersed with full throttle. An Altezza should do better.. assuming conservative driving style is telling the truth ;)

Continue to drive it and keep a track of the KM's, if it's been sitting for a couple of years then it might just need a decent thrash on the open road.
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Postby molex » Mon Sep 23, 2013 1:57 pm

Old BMW E39 540 would do 10.8L/100KM around auckland in traffic, so 12L in a 2 litre sounds pretty terrible. My 3.5L Blades worst ever tank was 440KM's from 50L with average speed of 12KM/h interspersed with full throttle. An Altezza should do better.. assuming conservative driving style is telling the truth ;)

Continue to drive it and keep a track of the KM's, if it's been sitting for a couple of years then it might just need a decent thrash on the open road.
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Postby edwagon » Mon Sep 23, 2013 2:21 pm

molex wrote:Old BMW E39 540 would do 10.8L/100KM around auckland in traffic

REALLY?


Oh, and 3s Altezzas are not cheap to run.
Have owned both auto and manual ones and its just a matter of fact

I found that you had to nurse them to get 10l/100km, and 11-12 wasn't out of the question.
About the same as my Aristo!
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Postby MAC_HATER » Mon Sep 23, 2013 2:28 pm

yeah definatly log some fill ups and see if you can see a pattern

and try to fill the tank each time, not half filling it, and note the kms traveled vs litres gone in, and you can work out a Litre\10 or 100km ratio, that you can keep in the log, as that's the number you are looking for, going by "kms per tank" is very inaccurate as the needle can have up to 50km before moving on the gauge if you are using that ect
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Postby Soiled » Mon Sep 23, 2013 7:56 pm

NA I used to average 500-550kms to 50 Litres, now I'm getting around 450kms to 50 litres if driving conservatively.

Both a mix of city and open driving, they shouldn't be that bad on gas. Regular oil changes (very temperamental on weight of oil) cleaning the MAF and throttle body, and running 98 octane petrol should all help.
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Postby molex » Tue Sep 24, 2013 3:29 pm

edwagon wrote:
molex wrote:Old BMW E39 540 would do 10.8L/100KM around auckland in traffic

REALLY?


Oh, and 3s Altezzas are not cheap to run.
Have owned both auto and manual ones and its just a matter of fact

I found that you had to nurse them to get 10l/100km, and 11-12 wasn't out of the question.
About the same as my Aristo!


Yep, that was its average across ~15,000km's. Was always driven nicely, it didn't need a lot of boot to get where you needed to go. Traffic was better then though :p That was what the dash computer reckoned anyway.

Weekend just gone drove total of 640KM's from 50L exactly in the Blade or 7.8L/100KM driving from Auckland to Northland and back, surely an Altezza should be the same or better?
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