PhoenixDownVII

Okay,



Call me crazy, but EVERYTIME I fill up my integra, I fill to full,...and hit the tripometer...and measure my MPG....EVERYTIME (paranoid? Nah).



Usually, I pull out 300 miles and have to fill up around 10 gallons...Hence a nice 30mpg car.



This week, I'm at 244 and the needle is getting close to where it used to read 300! That means I'll get 250 miles and 10 gallons....25 mpg!



As you know, the weather's been dangerously bitter for the past 2-3 days (I filled up before this freezin weather). But does the super-cold temps cause the Gasoline in my tank to somehow become thicker..and therefore the car uses "More" as it runs? Does anyone know if this is true?



Also, I've owned cars (And now this one is doing it) where the car's heat changes with your pedal-work. If you are in gear and are driving...it stays warm. But when you are in neutral or standing still (I.E. No acceleration)..the air cools down. In this cold weather, my heat doesn't get all that hot at all too. What could this be/mean? Do/Should I ge a new coil? Easy fix?



Argh, it's supposed to get warm soon, but I was just wondering....

ColinRX7

Sounds to me like it's overcooling.. Which (maybe) would explain a difference in gas mileage.. Not positive on that one though..



Try driving around with a piece of cardboard partially in front of the rad. That's something you see on just about every car up here when the weather dips to -20 or more..

Fluid Dynamics

You are not paranoid, just monitoring the car's health and your driving style.



Cold temps will do two things to MPG: increased warm-up time causes longer slightly rich running which uses more fuel than when warm. The oil is also more viscous when cold and imparts more parasite drag on the bearings and oil pump inside the engine, using extra energy up. Colder intake air creates denser air containing a more concentrated volume of O2 . . meaning that when you get on the gas, you will get more O2 going through the engine which will in turn cause the FI system to inject more fuel . . and you get more power but less MPG.



Right after my FC is warmed up but before the intake manifold gets heat-soaked is when it really rips, because the incoming air is still pretty cool while the engine is getting a proper fuel mixture, instead of being slightly rich, as it would be when cold. After it has been run for a while, it has less pep. This is why many modern cars have composite intake manifolds instead of aluminum . . so they won't be able to contain as much heat as aluminum and keep the incoming air cooler.

PhoenixDownVII

I almost never warm up my car. I've been told its both Good and Bad to warm up a car. But in the end, it makes sense to me to get the parts MOVING (Drive the car!) to get them warmed up. At the same time, I don't do anything crazy (No high rpms) for the warm up period as I'm driving anyways...



I think it could be just the super-cold weather.



Also, when I turn the heat on the temp guage lowers to under C a lot of the times. This is okay, considering when you turn the heat on you let it escape...and thats why...but under C? I dont' get it. One time recently I even had the heat off the whole ride and the needle didn't go much above the bottom line thats with C the whole time! How can an engine NEVER get warm? Doesn't make sense...



And in all of this, it's not as if my Temp guage doesn't work, because it has before/after showing some weird temps...



What do you think of my heat fluctuating? Is there a heat coil I could replace? Cheap and easy to do?

ColinRX7

Really, overcooling man.

FD3S DRIFT

maybe turn your fans off? just a thought

teknics

here's a FREE lesson in automotive.



when you start the car, everything is moving, you dont have to drive it to makes parts move, except the wheels and tires.



kevin.

turbovr6

the higher the rpms, the more heat is generated, the waterpump works more,the faster the coolant flows through the radiator.





Your thermostat may be stuck open if you never get above "C". and your heat is that low.

teknics

no no read his quote

"get the parts MOVING (Drive the car!)"



he's saying the only way for parts to move is to drive the car, im quite sure parts are moving when its idling.



kevin.

PhoenixDownVII

Riiiight.



In fact there are many parts that aren't moving much at all...considering you're in neutral and idling. I'm pretty sure certain parts move MORE and engage when you actually DRIVE.... I really didn't think only one piston runs or something...but thanks anyways...



Anyways, this whole "turn your fans off" and such isn't the point. Perhaps I didn't explain right:



I can drive for a half hour and the needles does rise (From UNDER C) to pretty much C. This is without heat blasting or anything. Normally, it should go to just under halfway between C and H.



Turning my fans off does help get that needle higher, and turning it on does lower it *a bit* like any car would show...