cold engine and gas mileage

[bruno8747]

I was reading on a maxima site that when the ecu knows that the engine is cold its adds about 10% more gas to warm up the car faster. So my question is do you burn more gas when you just jump in your car and drive if its not warmed up?
And today I had to make a quick run to the store like a couple blocks away and I just jumped in the car and left and then I saw my gas needle move down a quite a bit.

[JaiBeezy DnB]

I see the same shit also, i jsut got all my fluids changed, 5w30 synth, and well im only getting about 110 ay half tank. when it was warm out, i usually get 160 at half a tank. And im drining conservative, im not revving high most of the time, just keeping it at 3k rpm and such. I think cold does do something to it, but im not an expert so hope more folks post on here.

[bruno8747]

I heard that the gas stations have winter mix gas around this season. The winter mix is suppose to be different and have different additives to make your car start better. And the winter mix also burns faster so less gas mileage in the winter i guess.

[liquidx]

well im doing a school speech on fuel efficiency....and this one website talks about if you do a cold start

http://www.fueleconomy.gov/feg/factors.shtml

it says it dont matter

[JaK FRoSTWhiTE]

It shouldnt matter...

It even tells you in your OWNERS MANUAL.
You can start the car and let it idle for like a minute or two.

Then you can slowly take off, the car will warm up faster and thus
waste less fuel like that.

Its better than just standing there high idling at like
2k for like 5-6 mins waiting for the car to be warm.

[bruno8747]

http://www.fueleconomy.gov/feg/factors.shtml

Cold weather and frequent short trips can reduce fuel economy, since your engine doesn't operate efficiently until it is warmed up. In colder weather, it takes longer for your engine to warm, and on short trips, your vehicle operates a smaller percentage of time at the desired temperature. Note: Letting your car idle to warm-up doesn't help your fuel economy, it actually uses more fuel and creates more pollution.

According to that short trips on a cold engine reduces fuel economy

[F22-GURU]

well im doing a school speech on fuel efficiency....and this one website talks about if you do a cold start

http://www.fueleconomy.gov/feg/factors.shtml

it says it dont matter

Well, before you do your speech I think you better re-read that point and interprete the Note. Otherwise you will get a big fat "0"
and laughed at along the way.

Here is what is says.

Cold weather and frequent short trips can reduce fuel economy, since your engine doesn't operate efficiently until it is warmed up. In colder weather, it takes longer for your engine to warm, and on short trips, your vehicle operates a smaller percentage of time at the desired temperature. Note: Letting your car idle to warm-up doesn't help your fuel economy, it actually uses more fuel and creates more pollution.

It doesn't say "it doesn't matter" it says "Letting your car idle to warm-up doesn't help your fuel economy, it actually uses more fuel ]"
Plus if you read the first line is states it there as well.
"Cold weather and frequent short trips can reduce fuel economy, since your engine doesn't operate efficiently until it is warmed up.

[Bongo]

I heard that the gas stations have winter mix gas around this season. The winter mix is suppose to be different and have different additives to make your car start better. And the winter mix also burns faster so less gas mileage in the winter i guess.

i'm pretty sure they just use the same gas all year round....at least that's what they used at the station my friends dad owns /i used to work at. but they sometimes put drygas in for you but they'd tell you before they did it....but other than that it's just the same gas.

[liquidx]

Well, before you do your speech I think you better re-read that point and interprete the Note. Otherwise you will get a big fat "0"
and laughed at along the way.

Here is what is says.

Cold weather and frequent short trips can reduce fuel economy, since your engine doesn't operate efficiently until it is warmed up. In colder weather, it takes longer for your engine to warm, and on short trips, your vehicle operates a smaller percentage of time at the desired temperature. Note: Letting your car idle to warm-up doesn't help your fuel economy, it actually uses more fuel and creates more pollution.

It doesn't say "it doesn't matter" it says "Letting your car idle to warm-up doesn't help your fuel economy, it actually uses more fuel ]"
Plus if you read the first line is states it there as well.
"Cold weather and frequent short trips can reduce fuel economy, since your engine doesn't operate efficiently until it is warmed up.

LOL gyeah.....i know i read that back again along time good looking out ....

[SteveB]

i'm pretty sure they just use the same gas all year round....at least that's what they used at the station my friends dad owns /i used to work at. but they sometimes put drygas in for you but they'd tell you before they did it....but other than that it's just the same gas.

Gas stations don't mix gas.
Fuel distributors mix gas at bulk plants.

[SteveB]

I was reading on a maxima site that when the ecu knows that the engine is cold its adds about 10% more gas to warm up the car faster.

Well, no, it runs a fatter mix to actually get the "right" mix, because atomisation is compromised in cold temps.