R Z

Greetings. When I get in my car and press the start, the engine revs at pretty high rpms for a few moments(mainly the first time of the day). So, I figure, I'll just let the car sit in park until it drops and then back out of the garage and head on.

Do any of you do this or do you press start and take off? Does it even matter?

Just wondering. Thanks, Ron

CRowe14

Hey Ron:
I wish I could recall the thread, but it would be like trying to find a needle in a haystack.
Quite some time ago, there was a thread discussing idle rate rpm's and I asked about rpm's upon start-up, allowing the car to warm up and how long should I wait before placing the car into drive.
When I start my car for the first time in the morning, it revs high for about 5-7 seconds then nearly immediately revs down. I cant currently recall the numbers, but it happens every morning and I believe this is the case with all vehicles.
Devh (if you see this good buddy, please feel free to chime in or correct my statement if incorrect), took the time to respond and stated that he deemed this occurrence normal - once the flow of oil coat's the pistons/walls (about 11-1200rpm) will be the proper parked idle rate.
When putting it in drive (or in my case reverse) my rpm's drop to about 900 as the engine is then under load.
Another thing he mentioned/addressed was warm-up time.
He referenced an article, but in summation, stated that allowing your car to warm up for an extended period of time actually does more harm than good, as the fuel isn't being burned off at the rate that it would be while driving, and it actually thins out the oil (forgive my lack of technical facts here). A good 30-45 seconds should be plenty of time, even in cold weather conditions.
The idea is that getting the engine lubricated while under load (and not rapidly accelerating)- taking it easy for the first few miles, is better for the engine and oil.

Littleguy

I let the car idle for about 1-2 minutes when I start, to let the rpm's settle, and taking it easy the first few minutes/miles like CRowe14 said is probably just as important/good for the engine. No goosing it until the engine is at full operating temperature.

SW17LS

Idling the car for 1-2 minutes just increases fuel consumption and if anything it increases wear because you're idling at lower operating temps for longer than you would be if you were driving and the engine got up to operating temp more quickly.

If Lexus thought a warmup idle was important, they would direct us to do that.

comotiger

I am with you. Engine control systems are pretty sophisticated and they adjust fuel parameters according to engine temp etc. to ensure smooth operation without warming up the engine. There could be some sound basis for not gunning the engine before reaching typical operating temperatures (lubrication of pistons etc.). But idling the engine before driving off, except to have a warm cabin during the winter, is unnecessary.

SW17LS

Yeah I wouldn't gun the engine, but no reason to idle to warm up.

Dr. Jekyll

iTrader: (1)

Maybe I'm just lucky to live in an environment that changes within 10 degrees annually but my car never revs on start up. Once she's fired up I get on my way. Purrs like a kitten from the get go.

R Z

My car starts perfect and first start of the day it idles high but for maybe 5 - 15 seconds at the most. So, I just wait for it to idle down and back up.

Doublebase

All engines should idle high for about 7 seconds, it's called flare. The idle air control motor allows a larger quantity of air to bypass the valve, revving the engine higher to handle the load the alternator initially places on an engine. There are other factors that will also cause this...cold starts, air conditioner use, power steering being turned all the way to the locks. The LS460 doesn't incorporate all these scenarios (uses electric steering instead of hydraulic power steering). And it also doesn't use an IAC valve (as far as I know). Instead the drive by wire system opens the throttle plates slightly more in the same situations (instead of using a valve).

Personally I'd wait until the flare ends just to limit unnecessary stress on the drive train.

enoch861

Every car when started cold (Less than 70 degrees I believe) starts off higher than normal. But you're good to immediately. At around 30 degrees most cars will also start holding gears (typically 1 to 2 or 2 to 3) a bit longer than usual to allow trans fluid to warm up quicker. The only time I allow for slight idling (about 2 minutes or so) is during extreme cold typically less than 15 degrees out. I only do this to let the seats and steering wheel heat up before driving off.

RayLS

I wait at least a minute before driving off then drive slow for the first couple of miles.

PMIRO2

I do the same thing RZ. Wait about 10-15 seconds before backing out.

wayfar

I always wait for the revs to settle down before driving away.

7milesout

I'm mostly inline with this thinking. Although I don't think anyone responding here is wrong, or way off. I don't put mine in gear until it's down to maybe 1,200 - 1,300 rpm idling, due to the same stress on the drivetrain as Doublebase mentioned. My guess was that this "flare" while likely doing as you guys state, also or maybe primarily accelerates the lighting of the catalyst. That's why it cranks this way even on a warm engine. But I'm just guessing.


7milesout

Nospinzone

As soon as it starts I drive off, even in the coldest days of winter. The key is I keep the revs and the speed down.

What is just as important as warming the engine before going to higher revs, is warming all the other components/fluids before faster driving. Depending on what you are driving, the power steering fluid, brake fluid, transmission fluid, differential oil, gearbox oil, shock absorber oil/fluid and tires all need to warm up. None of those things warm up sitting in the driveway idling the car.