Not talking weather specific locals...just purely for engine longevity's sake. I've always heard that it's terrible to just start 'er up and take off, and also that it's pointless or even bad to let the car sit at idle for a while every time you start it up. Very curious.

 

I always let it get to operating temp before I drive. I look at it as someone waking me up and wanting me to run a 5min mile right off the bat. Not the best analogy but hey, you get it.

 

I get it, but its wrong. Your body works different from an internal combustion engine.

I think a 30 second warmup is ideal, not for water temp, just enough time to get the oil pressure up and into all the nooks and crannies. Then drive it like its just a grocery getter for 5 - 10 minutes, then go ahead and slam it.

The "myth" you speak of comes from old carbeurated days when poor atomization was a problem due to a cold carbeurator and intake manifold. However, with an EFI system, the excess fuel required at startup can wash down cylinder walls and promote scarring. This is why its bad to let the engine idle for an excessively long amount of time.

 

very interesting...well alright! My lack of patience was actually beneficial for once. Thx.

 

I always let it sit for a minute or two before taking off. On all the cars I've had, it's a must-do for me. Like said above tho, just to build some oil pressure and let the o2 sensor warm up...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LsVtec92Hatch &raquo;</TD></TR><TR><TD CLASS="quote">I get it, but its wrong. Your body works different from an internal combustion engine.

I think a 30 second warmup is ideal, not for water temp, just enough time to get the oil pressure up and into all the nooks and crannies. Then drive it like its just a grocery getter for 5 - 10 minutes, then go ahead and slam it.

The "myth" you speak of comes from old carbeurated days when poor atomization was a problem due to a cold carbeurator and intake manifold. However, with an EFI system, the excess fuel required at startup can wash down cylinder walls and promote scarring. This is why its bad to let the engine idle for an excessively long amount of time.</TD></TR></TABLE>

My opinion is basically the exact same as this mans, not positive about the idling part though.

 

The idle thing makes sense. I've spent some time in engine labs (research engines, not dyno cells) and spent one summer doing nothing but cold-start testing. Even with our direct injection setup it was amazing how much unburned hydrocarbons were produced in the first few cycles before the cylinder walls heated up. It would have been worse with a standard EFI system. My understanding is that you need to inject extra fuel at startup because fuel will form a film on the metal parts of a cold engine. You can't burn the film so you the extra fuel is there to make a combustible mixture. So the faster you get it up to temp the happier it will be. Idling won't do that for you.

 

Something else....


When the car has been sitting for a long time, all the oil from the motor has run down into the sump and cooled. When it cools, it gets more viscous. It take more work for the engine to suck the oil up out of the sump during idle right after startup.

I usually start driving right away. Note- I don't bounce it off the rev limiter or anything, but normal driving....give it some load. Get the oil pump spinning....saturate the motor as fast as possible.

Also, the car warms up faster if you drive it. The faster you get to operating temp the better!

 

another myth/rumor i have heard...... if your running forged pistons you should def. let it warm up some, since they swell with heat, they can tend to be a little loose/sloppy when you first startup

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by doublejz &raquo;</TD></TR><TR><TD CLASS="quote">another myth/rumor i have heard...... if your running forged pistons you should def. let it warm up some, since they swell with heat, they can tend to be a little loose/sloppy when you first startup</TD></TR></TABLE>

Piston slap.

Yeah, that is a side effect of having forged pistons, but I think if everything is spec'ed right you won't get that.

 

The owners manual on my 98 civic ex said that you only need to let the car "warm up" for about one minute. Any longer and you were just wasting gas.

However I recently installed an oil pressure guage and found that it takes a while for the oil to get up to temp and thin down to its normal state. On startup oil pressure is about 85psi at idle. After a 1min warmup and about 5min of driving it is about 30psi at idle. Once fully up to temp it is about 15-20psi at idle.

So the car doesn't need a long warmup, but I do like to warm it up for a minute or two.

 

I know you're not talking weather-specific, but I always try to wait until the RPM's are leveling off; usually 10-30 seconds, little longer in winter.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LsVtec92Hatch &raquo;</TD></TR><TR><TD CLASS="quote">I get it, but its wrong. Your body works different from an internal combustion engine.

I think a 30 second warmup is ideal, not for water temp, just enough time to get the oil pressure up and into all the nooks and crannies. Then drive it like its just a grocery getter for 5 - 10 minutes, then go ahead and slam it.

The "myth" you speak of comes from old carbeurated days when poor atomization was a problem due to a cold carbeurator and intake manifold. However, with an EFI system, the excess fuel required at startup can wash down cylinder walls and promote scarring. This is why its bad to let the engine idle for an excessively long amount of time.</TD></TR></TABLE>

Nicely put Steve BTW according to my driver's manual Honda states I should drive it until it reaches normal tempertures and no waiting for it to reach normal temps before I drive it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MrHeeltoe &raquo;</TD></TR><TR><TD CLASS="quote">Something else....


When the car has been sitting for a long time, all the oil from the motor has run down into the sump and cooled. When it cools, it gets more viscous. It take more work for the engine to suck the oil up out of the sump during idle right after startup.

Get the oil pump spinning....saturate the motor as fast as possible.

Also, the car warms up faster if you drive it. The faster you get to operating temp the better!</TD></TR></TABLE>

Ummmm... the oil is thinner when cold. Then thickens up when heated.
Also, once your car turns over the oil pump is turning. and the oil galleries are already filled, if you've run the engine before.

 

when i start my car, it idles at 2k, and then slowly goes down to 1.5k, and then goes down to 1.3k, that's when i start driving it. usually takes about 3-4 minutes

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GXPfire &raquo;</TD></TR><TR><TD CLASS="quote">

Ummmm... the oil is thinner when cold. Then thickens up when heated.</TD></TR></TABLE>

This is only true on the Bazzaro World.Here on Earth normal laws of physics still apply.
Glenn

 

GXPfire

ummmm you sure about that?????? maybe you should put an oil gauge in your car, look at the pressure when you first start it and let it sit there idling, the oil pressure will drop some once the car heats up = hot oil is thinner then cold oil.

 

i agree hot oil is going to be thinner, then when its cold.ITs common since anyways.Cause if it got thick when it got hot, then it would not lubricate as good, you would just get it so warm that it would turn to goo.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GXPfire &raquo;</TD></TR><TR><TD CLASS="quote">Ummmm... the oil is thinner when cold. Then thickens up when heated.
Also, once your car turns over the oil pump is turning. and the oil galleries are already filled, if you've run the engine before.</TD></TR></TABLE>

 

keep in mind that the stock ecu and iacv system (and others)all hel p keep a cold engine more healthy

with my itbs and lack of these systems ,as soon as i start my car it ges right to 800 rpm...the problem with this is that my oil light can stay on for a few seconds if i dont rev it abit .

the iacv brings a cols engine up to about 1500 to 2000 rpm to help oil circulation

 

I have a question, when starting a cold car, I usually turn my key to " on " and wait for the fuel pump to stop and the cel to go off..... what im asking is, is it better to just turn the key to ignition instantly or is pressurizing the fuel system ok?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by btownSI &raquo;</TD></TR><TR><TD CLASS="quote">I have a question, when starting a cold car, I usually turn my key to " on " and wait for the fuel pump to stop and the cel to go off..... what im asking is, is it better to just turn the key to ignition instantly or is pressurizing the fuel system ok? </TD></TR></TABLE>

If pressurizing the system first was a negative, do you think Honda would enable that by putting the key in the on position?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by btownSI &raquo;</TD></TR><TR><TD CLASS="quote">I have a question, when starting a cold car, I usually turn my key to " on " and wait for the fuel pump to stop and the cel to go off..... what im asking is, is it better to just turn the key to ignition instantly or is pressurizing the fuel system ok? </TD></TR></TABLE>

That technique would only apply if you had a diesel engine. As soon as you start cranking the engine, the fuel pressure will automatically start to be pressurized so no you don't have to do it.

 

The main thing you want to do is let the oil pressure get to normal. This usually takes 25-35 seconds after you start it up. If you waited for the car to warm up, you would be sitting for like 5-10 minutes, nobody does that. Also, its a good idea to invest in an Accusump. Its a 2-3 qt. cylinder--that holds extra oil and pushes into your motor when your oil pressure drops--such as in a long corner. You can also use it to prelube your motor before you start it--this way your motor has 30-50 psi, before you turn the ign. on! Jay. Its a Canton Accusump--look them up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by btownSI &raquo;</TD></TR><TR><TD CLASS="quote">I have a question, when starting a cold car, I usually turn my key to " on " and wait for the fuel pump to stop and the cel to go off..... what im asking is, is it better to just turn the key to ignition instantly or is pressurizing the fuel system ok? </TD></TR></TABLE>


I don't know if it's really any benefit to anything, but I do it if for my own peace of mind if nothing else - llisten for the fuel pump, watch the lights, see if anything looks/sounds out of place.