Why lower gas mileage in winter?

My 94 dodge caravan makes 400-440 miles per tank of gas (17-18 Gal) in the summers in the last 3 years, but only 340-370 in the winters. The driving pattern is about the same all year around, i.e. mixed city and highway driving. Anybody know why this is the case? Is there anything wrong with the van that caused this? Thanks.

John

Reply to
John Xu
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If you live anywhere cold, they mix the gas with cheaper alcohol and call it antifreeze or 'winter gas'. The mileage then drops like crazy so they get you for more money two ways.

In the 'old' days we spent 50 cents on a bottle of gas line antifreeze and added it with a fill. We then got our regular gas mileage.

I also drop about 100 miles per tank on the crap.

Pure rip off money grab!

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

John Xu wrote:

Reply to
Mike Romain

Faulty sensors can cause the PCM to run the engine cooler in cold weather, but more likely it's that your area has a different blend of fuel being sold in the winter months, the oxygenated blends have less energy per unit volume so you would get less mileage on them.

JazzMan

Reply to
JazzMan

Do you let your vehicle warm up longer before driving it in the winter? I do, so I can have some heat inside and the windows clear before driving. That warm up time of a few minutes versus 20 or 30 seconds makes a big difference. Just a thought.

Reply to
someone

I haven't found idling makes much of a difference at all. A few minutes of driving versus 20 or 30 seconds of driving does though.

-Bruce

Reply to
Bruce Chang

It's mostly because you car really burns more gas. Not because it's broken but because it consumes larger amounts of air thus it needs more fuel to function. If you've noticed your car might accelerate faster, etc. That's normal in cold weather. Reason is air compresses in cold weather so much more air reaches the engine and thus more gas is needed to burn it.

--Viktor

Reply to
electricked

Pretty simple really. Gas in many areas is reformulated with alcohol in the winter to prevent water in fuel systems from freezing, also it reduces smog. Alcohol has a lower energy content than gas so your engine has to burn more fuel air mixture for the same horsepower output. If you put a scanner on your car and looked at a graph of the throttle position in summer vs winter you would find on average in winter your throttle is open more.

As for the cold air is denser explanation, this isn't the case in a computer controlled engine because the engine computer looks at the mass air flow, the O2 in the exhaust, and several other factors to compensate for the denser air and maintain the same fuel air mix. The driver of course unconsciously compensates by not opening the throttle as much.

Ted

Reply to
Ted Mittelstaedt

I suppose cold grease helps, But if I use that alcohol or ethanol mix in the summer, my gas mileage drops just as bad.

Companies that promote the crap as 'cleaner' are point blank ripping you off. Sure the junk burns 'cleaner' maybe ounce for ounce, but if you need to use twice as much of it, well... so much for 'cleaner burning'....

Mike

Bob wrote:

Reply to
Mike Romain

When the car is cold, and the outside air is cold, even with fuel injection there will be some difference in fuel consumption until it has reached operating level.

The gasoline blend suggestion may also be a contributor.

Reply to
HLS
  1. Engine warm-up times are longer to reach operating temperature. A engine running at below operating temperature burns more gas. Short trips make the winter gas usage even more of a problem.

  1. High drain electrical devices tax the alternator that draws horsepower from the engine. Items such as lights, rear defogger, heated seats, blower motors, all consume electricity and the gas to generate it.

  2. Winter gas formulations seem to contribute as well.
Reply to
James C. Reeves

"John Xu" wrote in news: snipped-for-privacy@corp.supernews.com:

This is pretty much true for all vehicles in a cold climate. It takes much longer for the engine to warm up in winter. While the engine is cold, the engine control computer makes the fuel mixture richer, so you're burning more gas. (Just like the choke made the mixture richer on cars with carburetors.)

To take an extreme example: Suppose you drove your car to work, stop and go driving on city streets, 5 miles each way.

- In summer, the engine would quickly warm up and you'd get normal mileage for city driving.

- In winter, in a cold climate, your engine might not even warm up completely before you got to work and shut the engine off. So you'd be driving with a richer mixture to work and back every day. Lousy mileage!

Reply to
Jim Land

Ethanol has about half the BTU's of gasoline so it should take about twice as much to do the same job. Since blended fuel is not supposed to contain over 10% ethanol it really shouldn't affect your milage by more than 5%. What kind of difference are you seeing?

At least you have a choice what fuel you chose to run, here in MN we are stuck with blended fuel thanks to our legislators and it DOES cause problems. Bob

Reply to
Bob

I have a 4.2L carb engine with a hot spark and hot timing curve running a straight pipe with a high flow muffler.

When I run a mix, my engine will barely idle and it loses all power and starts rattling (timing ping) at about 65 mph.

My mileage drops to being out of gas at 225 miles vs looking for the next gas station when I hit 350 miles or 19 US mpg with 'real' gasoline.

I run high octane 91 or 92 gas.

If I run on regular, I also lose about 100 miles per tank, so the old thing is picky. Well it has the aerodynamics of a brick, so any extra I have to push on the gas pedal makes a radical difference in consumption.

Mike

Bob wrote:

Reply to
Mike Romain

You are dropping from 24 MPG to 21 MPG , based on the numbers you gave for range. I suspect that there are a variety of reasons for this.

Are you calculating mileage ? Or just basing this on how far you've gone to the same fuel gage reading ? You are talking about 2-3 gallons difference per fill-up, and you may be putting less in, since you are having to stand in the cold to do it, and want to get finished faster.

You probably let the van warm up a bit more when its cold, than when its warm.

The fuel mixture runs richer when the engine is cold, all of you short trips will be much less efficient, as the engine is colder for a greater percentage of the time.

Denser air requires more fuel for the correct mixture, although colder fuel will help balance this problem.

The fuel may, or may not, be reformulated in the winter, but it is to reduce fuel line freeze-up, not to sell more fuel. When the oil companies want more profit, they just raise the price, they don't have to do anything complicated and expensive line adding alcohol to the fuel.

Reply to
john.riedel

You also burn more fuel in winter because a car has to work harder to move through ice and snow. As for price, I've researched a.d owned shares in "integrated" oil companies here in Canada. The refining end of the business is marginal and competitive. That's why you see the price change so much at the pump. If the price were controlled it would be a lot more steady, like the tax component of the price. In Canada car owners pay a lot more in gasoline tax then the government puts back into roads and bridges. Paradoxically the roads are not in great condition. That's politics.

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Reply to
William R. Watt

It may be a combination of increased rolling resistance (due to crap on the raods) and increased aerodynamic drag through colder, denser air.

Reply to
Richard Bell

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