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Fuel Consumption VS Temperature
Posted: Tue May 09, 2006 9:43 am
by Nacho
Just want to start a discussion about how air temperature effects fuel consumption. Lately I've been trying to diagnose why my standard 500km per tank recently dropped to 400km not having changed my daily routes or driving style.
It only really started over the last 1 or 2 months when it's started to get colder. Now this is where my mind keeps going off in tangents.
If the air is cold, does it apply a thinner or thicker mixture of petrol?
Posted: Tue May 09, 2006 10:46 am
by Bennoz
If the air is cold, it is denser. If its denser, more fuel can react with it in the same space. Feel like you got more power? Probably cause you do...
Posted: Tue May 09, 2006 12:46 pm
by SG
ECU might be adjusting a bit and putting some more fuel in with the denser air
Posted: Tue May 09, 2006 3:12 pm
by artful_dodger
yeah ive noticed that
the fighter pilot thumbs have been out and i have more power
Posted: Tue May 09, 2006 6:11 pm
by Rocco
I seem to be getting better fuel economy of late...don't know why but definately not complaining with fuel prices as hish as they currently stand
Posted: Wed May 10, 2006 8:50 am
by Nacho
Yes we all love the cool weather coz we all get to hear the MIVEC roar louder.
So if the air is denser, is it right to believe that the ECU mixes less fuel in the mixture?
From trying to get my head around it, if it was really hot day, the ECU would want a richer mixture to prevent detonation. True or False?
Posted: Wed May 10, 2006 9:09 am
by Bennoz
Ass about
cold = dense = more fuel added to react with the abundance of air
Posted: Wed May 10, 2006 9:41 am
by robsta
thats strange, cause I have done almost 550km and I have used about 3/4 of a tank
better then normal for me
Posted: Wed May 10, 2006 9:46 am
by Bennoz
Understand, a dense reaction tends to be a more efficient reaction if tuned properly.... no wastage due to improper combustion (like pinging) so your fuel consumption may vary.
Re: Fuel Consumption VS Temperature
Posted: Wed May 10, 2006 11:43 am
by bobz
Nacho wrote:Just want to start a discussion about how air temperature effects fuel consumption. Lately I've been trying to diagnose why my standard 500km per tank recently dropped to 400km not having changed my daily routes or driving style.
It only really started over the last 1 or 2 months when it's started to get colder. Now this is where my mind keeps going off in tangents.
If the air is cold, does it apply a thinner or thicker mixture of petrol?
It could be because the cold start system is operating for longer and running the car rich for 5 minutes instead of 1 or 2 or your O2 sensor could be failing and running the car rich to prevent engine failure it could also be a problem with your MAF/MAP sensor.
BobZ
Posted: Thu May 18, 2006 9:10 am
by Nacho
So is it worth looking into then? I guess it's just a bit annoying with the fuel prices at the moment.
Would fuel filter possibly affect this situation at all?
Posted: Thu May 18, 2006 10:57 am
by Bennoz
Go get a dyno. It will tell you if the the A/F maps are out & probably diagnose if the 02 sensor is shot as well. Check ECU codes first thou.