Warm up idle or drive and go?

[Oilgal]

I finally asked my engine builder/custom fabricator friend about this, and he says I am full of beans about letting it idle so long to warm up.

He has dispelled a lot of "mythical stuff" I was wrongly taught, when I began to learn about cars a few years ago, and his advice has always panned out gold. I should have asked him about this sooner. He is well respected in these parts.

So from now on I will just start and drive, taking it easy until it fully warms up.

I may wait the 50 seconds or so for the A/F gauge to start cycling, when the O2 sensor is warmed up, so it isn't fueling by the ecu default. He is an old school pre ecu big block V8 guy, and so I am on my own there. I figure 1 minute can't hurt though.

 

[Oilgal]

Do you have a turbo timer for shutdown? Also, have you ever thought about getting your compressor side housing/wheel, heat block/stop coated?

 

[02zx9r]

Have people ever had situations where letting it idle till warm or just starting , waiting a minute then taking it easy have caused problems with the car?

Is there any proof that either way is better/worse? Really?

 

[Jethro]

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Do you have a turbo timer for shutdown? Also, have you ever thought about getting your compressor side housing/wheel, heat block/stop coated?

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My turbo is light pressure, so I usually just count to 15 or 30 seconds before shutting it down. If I have just been running hard, I'll give it a minute.

My warm-ups consist of idling for 15 seconds and then going easy on the throttle for a few minutes. Getting out of my apartment complex accomplishes this.

If I throttle it hard without the engine being warmed up, I am instantly greeted with a Check Engine light. It always goes off on the next startup. Picky car.

 

[blueiedgod]

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When a car is sitting outside in the winter … say … -20C (-4F) overnight, if one starts it, idles for 1 minute then drives off, you will be throwing a … lot … more fuel through an engine that is not running very efficiently (because it is so cold) than if the engine is warmed up. The least amount of fuel one can put through a cold engine during warm-up is by letting it idle.

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Yeah, but when you are idling stationary, you are not getting anywhere closer to your destination. So, on top of throwing out a ton of fuel into the exhaust pipe (running rich) are are also getting 0 MPG.

If you warming up while driving, you are getting closer to your destination, while throwing fuel out the tail pipe. You get some MPG, rather than none.

 

[blueiedgod]

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But Bluei, the heater is part of the inner loop.
It is on every car I've ever worked on.

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It may be on most, I get no heat out of my heater until the water temperature reaches at least 100 F. I have ScanGaugeII and monitor water temp, along with air intake, MPG and ignition (it is fun to watch ignition retard and advance as you play with the throttle)

 

[Oilgal]

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Have people ever had situations where letting it idle till warm or just starting , waiting a minute then taking it easy have caused problems with the car?

Is there any proof that either way is better/worse? Really?

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I am obviously not an expert. That is why I had to ask about this.

I have seen no reliable proof either way. From doing a search and reading here, apparently UOAs show good as for wear metal at least, regarding either method. This tells me that it is matter of choice and personal belief. Since that appears to be the case, I now believe

, that it is unnecessary to spend gas and time with long warm-ups.

 

[Oilgal]

Ok. Thanks Jethro.

 

[Durango]

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Whats the general consensus on this? I usually start it up, wait a few seconds and take it really easy until the engine is warmed up.

I can't stand seeing people start up a cold engine and rev the ---- out of it thinking they are doing their car a favor.

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I've read that most European car makers suggest you to start and go because gas is so high in their countires. Because of fuel injection being a standard one doesn't have that morning stumble like if you had a carburator of the past years. For myself I like to start it up and let the engine idle for about a minute before starting off to work. Driving slowly in the morning will warm the engine better and save you some gas in the process. It also helps circulate the oil better through out the engine.

Durango

 

[DB_Cooper]

Thirty or more years ago a very respected motorcycle tuner named Gordon Jennings wrote about the negative effects of idling, during warm up, on a cold engine. His concerns were the very rich mixture on the cold cylinders washing the oil off the bores. He stated that by driving off, with careful attention to the tach and allowing the oil to warm, purged the cylinders of fuel and allowed the engine to warm more quickly. I would agree that a smooth drive off once started has to be kinder to the engine. That rich mixture, at idle and cold cannot be of any benefit. Fuel dilution and bore wear would be the result.

 

[Dad2leia]

I used to be one of those that would let it idle for 3 minutes or so in the dead of winter. Now I too just let it idle for about a minute to get the oil circulating around, then drive off slowly, although sometimes the cold tranny doesn't want to go into a higher gear until the engine hits 3000 rpm, so I try to get it there slowly.

Most of my wear and tear idling now comes from having to leave it run to run in somewhere if the wife is with me to keep her warm and toasty. So what I gained in less wear with the prolonged idling sessions, I lost some with the fully warmed up idling sessions with fuel washing the cylinders.

Oh well...

 

[AFmedic]

When it's 20F and under I will be starting my truck and letting it warm up. Most morings in the winter are - single digit. Sorry but when it's cold it's nice to have a waremd up truck. MPG doesn't matter becuase I drive a Big truck. I will take heat over frigid for the sake of MPG and Fuel diluation.

 

[Patman]

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Have people ever had situations where letting it idle till warm or just starting , waiting a minute then taking it easy have caused problems with the car?

Is there any proof that either way is better/worse? Really?

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There probably never will be any tangible proof either way, but you might as well stick to the "non idling" side of things since it's simply money down the toilet when you idle your engine for longer periods in order to warm it up. The amount of $$$ you waste in fuel by idling so much over a 15 year period would probably pay for any engine rebuild you might possibly need! (but most likely won't need anyhow, so it's truly money in your pocket then)

The closest thing I have to any kind of proof is that I never idle my engine more than 15 seconds, even in -10F weather, and my UOAs always come back with very low wear numbers in my Corvette. So that shows me I'm not hurting my engine. I don't have comparison numbers with the same engine being warmed up by lots of idling though, and I don't intend to, as I refuse to waste my money like that. Unlike my idiot neighbor who idles her engine for 20min every morning, even if it's 40 degrees outside!

 

[Auto-Union]

Anyone who is around real complex machinery knows that some warm-up and cool-down is required. Tell the bone-head ricer kids and soccer moms that. They go to 100% output within seconds of starting. otoh, my friend with a few high-end heliocopters sits patiently with a countdown timer idling on each end of his runs. The rule of the highest good lies somewhere in the mean applies. Idle/warm lightly and fully, but don't sit there like a **** with a car idling for a half hour. Who wants to sit in a cold car anyway???

1sec/deg

 

[Ramblin Fever]

I do allow my personal vehicles some idle time on cold mornings, cause I hit an easy 3k rpm's the minute I leave the driveway - I don't care to hear the engine screaming every morning 3-5 seconds after starting the engine.

My company vehicle's a different story; I turn the key and 2 seconds later I'm off; probably shouldn't do this though - as this 2002 Ford Ranger does NOT like to take off and hit 3-4k rpm's within a matter of seconds. Bogs it down and looses all power, chugs too.

 

[Cutehumor]

coldest it gets here is 20 degrees during the winter, now this is at midnight when I'm not even driving the car. usually it's in the mid 30's if I'm driving the car during winter

 

[Shannow]

Been thinking about this a lot in the last few days.

Do you sell your car before you tow it to the junkyard ?

If you sell the car while it is in "reasonable" shape rather than trashed, then don't idle it warm, as every day you are spending money that you are giving the new owner (IF IDLING WORKS). If idling is bad, you are wasting money on fuel, plus life.

If you really run it into the ground, then pick your poison.

 

[blueiedgod]

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although sometimes the cold tranny doesn't want to go into a higher gear until the engine hits 3000 rpm

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Some automatics shift later when the coolant is cold. It is programmed into the computer.

If yours is manual and you can't shift it when its cold, it is time to change the tranny lube, and possibly damaged synchros.

 

[addyguy]

I start mine and let it idle while I scrape off the windows, as it is parked outside, so it sees 3-5 mins of idle time. If there is no ice/snow on it I still let it idle for a couple of minuites, as I feel it is dangerous to drive when your defroster can't clear the windows.

I get really angry at people in traffic who drive along, looking out of some 2" square at the bottom of the windsheild....either scrape the whole thing off, or let the car warm up an do it itself. If it takes 5-7 mions for this to happen, so be it. At least I'm safer.......

 

[Drew99GT]

I start the engine, and immediately start revving the ---- out of it to clear it up. Once the blue smoke really starts pouring out, it's my signal to bounce it off the rev limiter once or twice to clear it out some more so it will actually idle. Once it starts sputtering and wants to stall, 3 more bounces off the rev limiter. I then rev the ---- out of it while backing out of the driveway. Once I hit the street, it's my signal to FLOOOOOOOOOOOOOOOOOOOOOOOOOOOR it and leave a huge cloud of blue smoke.

Actually, this is the daily routine for one of my neighbors who has a beater sing ray vette with a tired 350. If it's sunny, it gets driven around the block! Even if it's 20 degrees out. Sucker don't sound to good.

You should hear his Triumph Spitfire! ROD KNOCK.