I heard it is bad to warm up a fuel injected car. I did a search on this in the forums, but I need a more technical answer. Can anyone answer?

Thanks.

Acura recommends a 30 Sec warm up for our TLs. The first few minutes you drive your car after starting it up, you will get the worst MPG fuel ratio, so its best to warm up more.

You are wasting gas when you warm it up. Besides, if it is pretty warm (temperature wise.. like in Los Angeles), you won't need to warm it up.

Just don't drive aggressively until the engine is fully warmed up.

------------------
Y2K SiLVeR TL, non-navi
SLVR TL Homepage Last updated 6/9/01

I try to warm it up for at least 15-20 seconds when it's cold. My car stays in the garage so it's probably not too necessary. I just get in and drive in warmer weather.

------------------
<A HREF="http://www.adamoski.com/acura.html" TARGET=_blank> </A>

I also heard something about letting the car idle too long while parked puts a lot of stress on the car because you are letting the car idle while not under load(no load on the transmission because the car is in park). Does anybody know anything about this?

Unless its -20 degrees where you live, warming up any modern car is just wasting fuel. By the time you get your seatbelt on and are ready to roll, 30 seconds has already passed by and the car is ready for a ride :-)

As soon as the car settles down after you start it, just put it in drive and move off slowly until the car reaches normal operating temperatures. As for the worst MPG fuel ratio, remember one thing, an idling engine gets ZERO MPG.

not only its a waste of fuel, idling is one of the worst thing you can do to wear your engine parts. according to consumer reports, idling a warm engine for 30 seconds does more damage than a cold start. imagine how much more damage ur doing to your car during a cold idling.

Do you have any more information on this like technical specifics?

I remember reading an article that mentions that driving will increase oil circulation through the engine. Since an engine that has been sitting still is basically dry (all the oil is in the pan at the bottom of the engine), idling will actually cause more wear on the engine.

IMO -

The damage caused by letting your car "idle" to warm up is not a heat issue so much as it is a lack or balance of heat.

Basically when your car is idling it takes longer for the engine, exhaust and transmission to reach optimal operating temperatures. And all parts do not reach that point at the same time by just idling.

In a cold engine that is warming up there are many things different taking place. First the oil has to circulate to the upper parts of the engine. It takes a few seconds to do that. Depending on whether you are using a good quality oil and are changing it as recommended, then this is not a real concern because you still have an oil film providing some degree of protection until the oil is fully circulating to those parts of the engine. What is a concern is if you start it up and start racing the engine right away. That little bit of oil film provides minimal friction protection. In addition, stress on cold metal parts is also not a good thing. Cold parts are more rigid than hot parts and can be over-stressed and fracture.

The other thing that happens when an engine is first started it produces condensation within the engine, exhaust and transmission somewhat. So basically "water" is being produced during the warm up period. And until the all parts reach operating temperatures it'll increase friction and reduce power. When water vapors and all the other gases combine during the warm up period, acids are produced and the net is that this is what causes the most wear on a properly maintained car.

So, the best precautions that you can take to minimize those effects are to:
Use a good oil and change it regularly.
Let it idle for about 15-30 seconds, depending on how cold it is outside.
Start driving right away, but not too aggressively until full operating temperatures are reached. This depends on how cold it is and what type of driving you are doing. A good rule of thumb is to drive 10 miles or about 10-15 minutes.

Driving verses idling will warm up all parts more quickly and effeciently. Idling warms up the engine and exhaust, but the transmission warms up much more slowly because its not really doing much.

Once the parts reach full operating temperatures the water production is significantly reduced. Just watch a car on a cold day. Notice at first that it produces a white vapor. That's mostly water. After a while the exhaust begins to clear. That's because it being eliminated more quickly by the hotter engine and exhaust. And as a result it doesn't get mixed in with the oil causing that nasty oxidation. It also reduces the acids that are produced.

So idle for just a few seconds (10-30) and drive gently for the first 5-10 miles or 15 minutes.

Again these are my opinions and are based on what I recall from my years as a mechanic and hot rodder. Of course that has been some years ago,

RUF

------------------
2002 TLS WDP w/Ebony interior
Formula 1 35% Premier Tint

It's actually illegal to let your car idle to warm up in some countries (Sweeden?)

------------------
'01 White Diamond Pearl 3.2TL
-Wing, tint, wood and Whistler

In addition to what RUF87 pointed out, excessive idling will also shorten the life of your motor oil. Because during the cold temp in the engine, motor oil gets contaminated by tiny bit of fuel since the piston rings are not expanded like at normal temp. This is what I read from a technical article.

I thought warming up is good....

I would warm up my car in winter no matter what others said...

When the weather is 60 degrees or more, I wait about 210-15 seconds to warm up.. when it's colder, I wait a little longer.
Ed

------------------
Acura-TL.com - Forum Moderator
'66 Mustang Fastback
'99 Mazda Miata
'99 Acura TL Satin Silver/Ebony, Non/Nav, Comptech Springs and Sways, CL Type S wheels wrapped with 225/45/17 Dunlop SP9000's, Comptech Air Filter Element, Inspire Tails, AEM Brake Pads all around, Comptech Axle Back Exhaust, Gutter Guard Grille, "Guy Smiley" doll on the dash as my Co-driver...

Pics of my TL
Pics of my Miata! Wadya think?

You guys are confusing me...some say not to warm up too much, some say warm up? What to do?