Engine Warmup?

I'd like to know both the conventional wisdom about, and the
common practices you guys use, starting your Explorer after
it has been sitting outside all night in 40-60 degree temps.

Some of my friends start it and drive away immediately.
Another buddy lets it idle for 5 full minutes before moving.
I have tended to wait until I detected a slight uptick in
the temp gauge needle, but sometimes I'm in a hurry and only
wait 30-60 seconds.

Everything I've read on the topic is non-quantitative,
meaning the wording is "briefly" or "for a little while"
etc.

Thanks.

--
----------
CWLee
Former slayer of dragons; practice now limited to sacred
cows. Believing we should hire for quality, not quotas, and
promote for performance, not preferences.

I suggest you ask your 5-minute buddy to provide an explanation of why he is
doing that. Let's see what he comes up with.

Modern engines do not need to be 'warmed up' before driving. That's what
fuel injection, engine management computers, heated oxygen sensors, etc are
for. Unless you are preparing for a race and need maximum power from the
get-go, it makes no sense to burn $4/gas while going nowhere, not even for
your 30 seconds. A cold engine also wears more and pollutes much more than a
warm one, so the fastest you get it to operating temperature, the better.
And the way to do it is to start moving. Just my humble opinion, of course.

"CWLee" > wrote in message
...
>
> I'd like to know both the conventional wisdom about, and the common
> practices you guys use, starting your Explorer after it has been sitting
> outside all night in 40-60 degree temps.
>
> Some of my friends start it and drive away immediately. Another buddy lets
> it idle for 5 full minutes before moving. I have tended to wait until I
> detected a slight uptick in the temp gauge needle, but sometimes I'm in a
> hurry and only wait 30-60 seconds.
>

You make 40-60 degree F sound like it's cold.... This is "shirt-sleeve"
weather, my good man....

Start it up... give it a few seconds for the manufacturers recommended oil
viscosity grade to circulate and start driving it. Gently at first, allowing
yourself to get a little more agressive as the engine warms.

FWIW... starting the engine and allowing it to reach operating temp is still
going to leave the transmission and other driveline components cold. There
is nothing to be gained from this other than a "warm face".

"CWLee" > wrote in message
...
>
> I'd like to know both the conventional wisdom about, and the common
> practices you guys use, starting your Explorer after it has been sitting
> outside all night in 40-60 degree temps.
>
> Some of my friends start it and drive away immediately. Another buddy lets
> it idle for 5 full minutes before moving. I have tended to wait until I
> detected a slight uptick in the temp gauge needle, but sometimes I'm in a
> hurry and only wait 30-60 seconds.
>
> Everything I've read on the topic is non-quantitative, meaning the wording
> is "briefly" or "for a little while" etc.
>
> Thanks.
>
> --
> ----------
> CWLee
> Former slayer of dragons; practice now limited to sacred
> cows. Believing we should hire for quality, not quotas, and
> promote for performance, not preferences.
>

"CWLee" > wrote in message
...
>
> I'd like to know both the conventional wisdom about, and the
> common practices you guys use, starting your Explorer after
> it has been sitting outside all night in 40-60 degree temps.
>
> Some of my friends start it and drive away immediately.
> Another buddy lets it idle for 5 full minutes before moving.
> I have tended to wait until I detected a slight uptick in
> the temp gauge needle, but sometimes I'm in a hurry and only
> wait 30-60 seconds.
>
> Everything I've read on the topic is non-quantitative,
> meaning the wording is "briefly" or "for a little while"
> etc.
>
> Thanks.
>
> --
> ----------
> CWLee
> Former slayer of dragons; practice now limited to sacred
> cows. Believing we should hire for quality, not quotas, and
> promote for performance, not preferences.
>

First I turn on the ignition and let it set until it stops beeping. Then I
start it up and let my car idle until the idle speed drops to normal which
takes about 10-15 seconds usually.

I don't know if it's true or not but I've heard that when you first turn on
the ignition ('91 Explorer) the computer is checking all the sensors and
deciding how much air/fuel and all to give it depending upon how cold it is
and all.. In any case it probably can't hurt to wait 7 or 8 seconds before
starting it.

I also don't change direction while moving. If I back up I wait until the
car is completely stopped before shifting into D. Again, I don't know if
this really does any good...

Ulysses wrote:
> I also don't change direction while moving. If I back up I wait until the
> car is completely stopped before shifting into D. Again, I don't know if
> this really does any good...

Yes. Reversing direction on the drive train (vs bringing it to a stop then changing direction) will definitely wear it out faster.

David

It's just like turning on a computer... there is a POST (power on self test)
that occurs... The PCM checks sensors for baseline readings (paying
particular attention to barometric pressure, intake air temp and either
engine coolant temp or engine oil temp- comparing these to "look up" tables
to determine starting strategy) and may "sweep" some or all of the PCM
controlled actuators. Well known is that the fuel pump runs briefly to bring
the fuel rail to pressure, but the PCM may cycle other actuators that are
monitored to determine circuit integrity.

Even with the baud rates we had in the early 90s, there isn't really any
need to wait more than a second or two to ensure that the POST completes.

If you have the chance, open the hood and have an assistant turn the key to
the run position... you are sure to here at least a few little clicks and
clacks as the PCM performs it's duties.

"Ulysses" /> wrote in message
. ..
>
> "CWLee" > wrote in message
> ...
>>
>> I'd like to know both the conventional wisdom about, and the
>> common practices you guys use, starting your Explorer after
>> it has been sitting outside all night in 40-60 degree temps.
>>
>> Some of my friends start it and drive away immediately.
>> Another buddy lets it idle for 5 full minutes before moving.
>> I have tended to wait until I detected a slight uptick in
>> the temp gauge needle, but sometimes I'm in a hurry and only
>> wait 30-60 seconds.
>>
>> Everything I've read on the topic is non-quantitative,
>> meaning the wording is "briefly" or "for a little while"
>> etc.
>>
>> Thanks.
>>
>> --
>> ----------
>> CWLee
>> Former slayer of dragons; practice now limited to sacred
>> cows. Believing we should hire for quality, not quotas, and
>> promote for performance, not preferences.
>>
>
> First I turn on the ignition and let it set until it stops beeping. Then
> I
> start it up and let my car idle until the idle speed drops to normal which
> takes about 10-15 seconds usually.
>
> I don't know if it's true or not but I've heard that when you first turn
> on
> the ignition ('91 Explorer) the computer is checking all the sensors and
> deciding how much air/fuel and all to give it depending upon how cold it
> is
> and all.. In any case it probably can't hurt to wait 7 or 8 seconds
> before
> starting it.
>
> I also don't change direction while moving. If I back up I wait until the
> car is completely stopped before shifting into D. Again, I don't know if
> this really does any good...
>
>

> Another buddy lets it idle for 5 full minutes before moving.

And people wonder why gas is $4 a gallon.