I have noticed on the trip computer that i am consistantly getting 12l/100km at night and 14.7l/100km during the daytime. Since its only th air that changes at night time could it be that my temp gauge is rooted and its running alot hotter then it should? So at night it cools down a bit and runs how it was meant to?

Or could it be the air temp sensor? I have no idea what this actually does and have not tested it.

I have unplugged the comp over night and done an ecu test but keep getting 11 11.

Any help would be apreciated

cheers fellas!

Its colder.
Early frosty mornings cars perform at their peak.


Pollution and other crap is optimised during the day. the road also produces heat.

maybe you drive with caution at night too.

1. colder air
2. less traffic to contend with

ahhh fair enough then. So what exactly is the purpose of the air tempsensor? What does the ecu do if the air is to hot or to cold?

As I understand it the ACT tells ECU what ingoing air temp is and ECU adjusts fuel quantity delivered to suit. BUT there is a limit to the range it can cope with and also cold and moist air allows a richer mix to be burnt correctly.

Hope this is correct and I am sure some one will correct me if I have the wrong idea.

Cheers, Chris

colder air contains more oxygen, oxygen is what is needed to burn fuel efficiently, so you get a denser air fuel ratio with a better burn for more power at less throttle.

It makes the car run more efficiently, a car will make more power on a dyno on a cold day than a hot day....so most dyno comps especially horsepower heroes at the summer nats, has cars performing under the worst conditions possible.....

Ill agraa with xb coupe on that.
It is coz of the density of the air.
and also coz less traffic in a slight degree.