"Idle" Chat (rant)

[GasSavers_Brock]

Ya, I can tell you in a VW diesel idling does nothing. My wagon consumes .25L or .05gal / hours once warm. So there isn't enough heat to keep it warm. You have to drive it to make heat, no point in idling; it actually will cool the engine faster since it is sucking a lot of cold air through it.

Here in Wisconsin it is illegal to leave a car idling without a person in it. Which really struck me as odd since they can sell those remote start units. Wouldn't you technically have to break the law to even use them?

When it is really cold, like below 0F or -17C I let the car idle until the louder knocking stops, about 5-10 seconds before driving slowly away. I do drive slowly until I get some movement on the thermometer.

[LincolnW]

You should have taken the keys and thrown them out the window a few miles down the road! lol

No really, like already stated, these types of people don't care about anything but themselves. People like that really bug me. I can't stand wasteful people.

[rh77]

Originally Posted by theclencher

So p&g doesn't work for you?

I can efficiently engine-off coast in the Integra, but for some reason, the TSX just guzzles the gas on startup. It generally drops the overall MPG average displayed by 0.1, which would negate the whole purpose. The 'Teg is much different -- once it's warm, it's in closed-loop and you can Engine-off coast all over the place. I've been trying to figure out how long of having the engine off vs. idling. I kinda like the 15-second idea...

RH77

[Spule 4]

Long idle, in cold, to allow proper warm up is OK and is beneficial in the long term, but you are right on the letting things sit once warm, why bother?

Many years ago, two friends did find a warm running car when returning home from a night of drinking. Figured why not, and took it home....then a voice comes up (radio) and they notice it is an unmakred police car. They quicly bailed out of it....but one did leave a warm and wet surprise in it.....and a detective wondering where is car went.

Also, in Athens Ohio around 1990, there were a rash of pizza men that would leave their cars running and run to the door with the pizza. The pranksters (that called the guy) would jump out of the bushes and then drive the cars to the intermural football fields of south green and "launch" them in the Hocking River. Several reports of this in the Athens News at that time.

[rh77]

Originally Posted by theclencher

Now that there is pretty much 100% wrong.

I would agree there -- anything more than 5 seconds of idle time, even at 15F or colder, is wasting a LOT of fuel. The trick is to slowly drive until everything warms properly, then drive as normal.

Fuel maps support the theory.

RH77

[Spule 4]

Originally Posted by rh77

I would agree there -- anything more than 5 seconds of idle time, even at 15F or colder, is wasting a LOT of fuel. The trick is to slowly drive until everything warms properly, then drive as normal.

Fuel maps support the theory.

RH77

Maybe, I should be more clear, not a fuel issue, (but even then with choke on older cars) but engine wear, espeically diesel and turbo. Having torn down a few motors in my day that did not see this and those that did, you can tell, especially top end wear.

You can buy a lot of fuel for the cost of a motor.

[Spule 4]

Actually, the average car at idle takes around 1/2 gallon per hour of fuel, so even at 10 minutes to warm up, you are not approaching anything that would be a large negative impact on fuel and the benefits of a warm car for comfort are added also.

[Spule 4]

Interesting on cold temps in that one link, the coldest I have ever started a car and drove around (without problems I may add) was about -32F. The car? Volvo 122S. Yes, with SUs.

Not sure on the wear comment in the thread there.....have seen the wear and then there is in fact a negative FE from running a car not warmed up, drive one around with a bad thermostat for a while and see what happens even in summer.

Agreed on the idling all day, even the railroads in the US are getting away from it now.

[rh77]

Originally Posted by Spule 4

Actually, the average car at idle takes around 1/2 gallon per hour of fuel, so even at 10 minutes to warm up, you are not approaching anything that would be a large negative impact on fuel and the benefits of a warm car for comfort are added also.

On cold startup, the average car will use a LOT of fuel as it is on a pre-programmed "Open-Loop" -- meaning, it is going to run as rich as possible until coolant temps can allow the oxygen and other sensors to provide feedback (closed loop). I mean we're talking some serious consumption. Over 10 minutes, starting at 2.0gph and tapering to 0.7 (cars aren't generally warmed up until moving), you've burnt a considerable amount of fuel.

Taken from http://oee.nrcan.gc.ca/transportatio...nce.cfm?attr=8

"An engine can burn up to 50 % more fuel for a short trip in the winter than for the same trip in the summer.

Fuel combustion is also much less efficient in a cold engine, and the air-fuel mixture is richer (i.e., there is more fuel and less air). The combined effect is a sharp increase in pollutants. To make matters worse, the catalytic converter doesn't work when it is cold. Until the converter warms up, all the engine's emissions pass through the exhaust untreated.

One answer to this cold-engine dilemma is to use a block heater to warm the coolant, which in turn warms the engine block and lubricants. The engine will start more easily and reach its peak operating temperature faster. In temperatures below 0?C, block heaters can improve overall fuel economy by 10 % or more.

Use an automatic timer to switch on the block heater two hours before you plan to drive the vehicle. This is all the time needed to warm the engine.

Warm Up by Driving

Once a vehicle is running, the best way to warm it up is to drive it. With computer-controlled, fuel-injected engines, you need no more than 30 seconds of idling on winter days before driving away. Anything more simply wastes fuel and increases emissions.

Besides, more than the engine needs to be warmed up. So do the wheel bearings, steering, suspension, transmission and tires, and that can happen only when the vehicle is moving. For a typical vehicle, it takes at least five kilometres of driving to warm up these components.

Although it is important to drive away as soon as possible after a cold start (but not before the windows are defrosted!), you should avoid high speeds and rapid acceleration for the first five kilometres or so. The goal is to bring the whole vehicle up to peak operating temperature as quickly as possible while maximizing fuel economy.

To prevent your car windows from fogging up, open a window as soon as you enter the vehicle. Clear snow from the air intake on top of the hood. Otherwise, the defroster will draw moisture into the system and fog the windshield."

This can be cited over and over if necessary...

RH77

[Spule 4]

RH77

Very good article there from the Canadians. Very true on the points of the suspension. You and I can relate especially to Citroens in cold mornings firsthand, I have not experienced that in many many years myself, but can remember "stiff" times. Then, there are other cars that not all functions will work until warm including the older ACC systems in Mercedes and top gear on Toyota automatics from the 1980s on.

But, once again, and I am surprised as the article does not talk about the negatives of engine wear. And ditto too on cool down, especially diesels and turbos. Don't cut the engine when not at idle and give it a chance to "cool".