skinnadoor

Hi everyone....

So here is my snag..... , for the last 6 months that i've owned my 94 Toyota 4Runner, 4WD SR5 Auto.... i've been getting on avg, about 450km per tank "55L" around town and about 575km per tank on the highway. All is well with this scenario...fine by me.

About 3 weeks ago, the weather turnned very cold, and we've been gettting alot of snow..... The temperatures have be down around -20C, at night, and not much better during the day. NOW !!!! when my fuel guague reads halfway, instead of it being about 225km on the trip counter, it's around 150km.... ................. and i now stand to get only about 325-350km per tank of fuel....................................

My question...............................

Can extreem cold, or perhaps driving on snow covered roads for a tank of fuel, really throw off my fuel enconomy that much ???? And Are there any components in my 4runner, that function poorly in cold weather, which could also throw off my fuel economey....???

Has anyone else experianced a drop in fuel economy in the winter months??? i'm just curious, as it's my first winter with her.

Thanks for the help everyone.......

mr_lemons

I lived in Alaska for a long while and now Salt Lake City (both get cold) and my mileage always drops. I think it's because of a few things

1. Spinning tires- it happens in snow and you burn more gas
2. 4wd- that... just uses more gas
3. dense air- more air that gets sucked in then more fuel is mixed in to make your truck run right.
4. different gas-most places that get really cold switch to a different fuel mix for the winter

and that's all i can think of right now.

WillRadford

The cold air is denser, but if the fuel intake increased to compensate for the increased air mass reaching the engine, then wouldn't it act just like it did in the summer? You wouldn't even notice a difference? See, I thought that in the winter the dense air makes your truck more powerful since more air is reaching the engine with the same amount of fuel being sent. Thats the whole idea behind a turbo, cram more air in the cylinders.

Anyways, I live in Salt Lake also, and it has been REALLY cold lately, and I haven't really noticed much of a difference in gas millage.

Doesn't the engine run rich when its cold in order to warm up faster? I wonder if in the winter everytime you start your truck when its cold if you waist a lot of gas until its warmed up.

jfreisner

well no chit?

pdyebrasil

Hey! A bunch of Salt Lake guys! Hehe...

I think one of the biggest factors in the gas mileage decrease is the winter blend gas. But also, you'll notice that your engine idles MUCH higher than normal in order to reach normal operating temperature. So if you let your truck warm up before leaving you are burning extra gas w/out going anywhere. 4-wheel drive definitely will use more gas as well.

On the upside, colder air is denser, so you will notice that your engine is a little peppier in the winter months...

infiltrator

yeah, i just put in some irridium spark plugs, and im seeing a difference in my mileage. i know that will go up when the gas changes

ps gas is $3.37 a gallon :[

4rnr

Higher idles and spinning tires wont make a noticeable difference. 4wd will make a massive difference (3-5 mpg for me). Other than that, a different fuel makes sence to me and so does the MAF reading more air thus increasing fuel (But shoulnt it read flow not density, plus dense/cold air should increase power and if you drive carefully that extra power = less effort = more efficient)

Meh, what ever.

BTW I dropped from about 19.5 avg mpg to about 17 avg mpg as soon as it got cold. In fact it was like a light switch! One tank I was pushing 20mpg the next 17 mpg. So maybe a different fuel???

nate V

What kind of difference in fuel is there from summer to winter ....?
I have never heard of such a thing b4

elripster

A few things are at work here.

Fuel blend? Maybe, in CA we have a crappy winter blend that will take 10% easy off of your mpg.

Mixture: The engine takes longer to heat up and runs open loop for a longer period of time. This makes it run more rich for a longer time than in warm weather.

4th gear lock out: The auto won't shift into OD until the engine has reached operating temp. I hate that "feature" and plan to figure out how to disable it. Never the less if you are like me and live close enough to the freeway where you have to drive a while until the engine is warm... well nothing sucks fuel like an engine running open loop under load at 4K RPM...

4wd: That will make a big difference especially around town.

Any precipitation will decrease economy especially on the freeway.

I should add, dense air does not equal higher/lower fuel economy, just better performance. In fact, cold dense moist air is the best.

Frank

ewong

I lose 10% top 15% EVERY YEAR due to winter blend.

I lose more on the 4Runner - but my winter tires are larger (235/85R16 versus 31x10.5R15).

Mattabilly

I'd guess gas mixture, here we run oxygenated gas to keep pollution down. So the trade off is less pollution for considerably worse MPG.

pdyebrasil

Interesting... Everyone gets worse gas mileage, so they need to burn more fuel to get around. Not quite sure how that helps out the pollution problem.

Mattabilly

Exactly! Maybe it's cleaner pollution?

mr toytech

all normal, get used to it. its not just you, its every single car on the road does it.

jfreisner

Maybe it's global warming?

4rnr

I thought I saw Manbearpig retarding my timing......