Depends how cold. Summer temps wait 10 sec winter below 20f 30 sec then light throttle till some heat.
Who waits for the RPMs to settle before ...?
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gathermewool
Site Donor 2023
I wait for the secondary air injection pump to turn off, which is evidenced by vacuum returning to normal.
Originally Posted by Leo99
Originally Posted by TXCarGeek
I'm unsure what prompted me to do this, but do any of y'all wait for the RPMs to settle after a cold start before shifting into gear?
What's the precise reason for the higher revs to begin with? And is it at all beneficial to allow the engine to settle down like I have a tendency of doing?
Curious how old you are? Carburetored engines would close the choke and run very rich with high rpms until the engine warmed up. Back in the day, we might wait a little bit for the engine to warm up and we'd blip and gas pedal and get the rpms to settle down. Engines could be a little finicky when cold. Today computers control all that and I just get in and go.
I'm 26.
Originally Posted by TXCarGeek
I'm unsure what prompted me to do this, but do any of y'all wait for the RPMs to settle after a cold start before shifting into gear?
What's the precise reason for the higher revs to begin with? And is it at all beneficial to allow the engine to settle down like I have a tendency of doing?
Curious how old you are? Carburetored engines would close the choke and run very rich with high rpms until the engine warmed up. Back in the day, we might wait a little bit for the engine to warm up and we'd blip and gas pedal and get the rpms to settle down. Engines could be a little finicky when cold. Today computers control all that and I just get in and go.
I'm 26.
Doesn't seem like there's a consensus as to why modern vehicles cold start with a high idle for a few seconds.
I think it's worth noting that I'm not talking about letting your car idle for an extended period of time to bring it up to temp. Doing that has been thoroughly debunked as being useless and a waste of fuel with modern vehicles. I'm talking specifically about the few seconds after starting where the idle is higher than normal and eventually settles down to normal...
I think it's worth noting that I'm not talking about letting your car idle for an extended period of time to bring it up to temp. Doing that has been thoroughly debunked as being useless and a waste of fuel with modern vehicles. I'm talking specifically about the few seconds after starting where the idle is higher than normal and eventually settles down to normal...
Originally Posted by Nick1994
I let it settle down. Takes maybe 10 seconds in the Genesis unless it's already warm out. Same with the Camry. My Jeep doesn't have a high idle on cold start but I still wait 10 seconds or so.
My parent's Genesis with the 5.0 settles down very quickly as well. Much quicker than my '08 550i. My '99 Wrangler with the 4.0 is like yours as well...no high idle at cold start.
I let it settle down. Takes maybe 10 seconds in the Genesis unless it's already warm out. Same with the Camry. My Jeep doesn't have a high idle on cold start but I still wait 10 seconds or so.
My parent's Genesis with the 5.0 settles down very quickly as well. Much quicker than my '08 550i. My '99 Wrangler with the 4.0 is like yours as well...no high idle at cold start.
The higher revs are to get the catalytic converter(s) up to temp faster. I let the engine come down before taking off unless I'm in a huge hurry.
I always let mine idle till the RPM's come down. In the winter it may take 30-40 sec and in the summer only 5 or 10. I want to be sure there is plenty of oil everywhere it needs to be and I dont want oil pressure rising too fast with the filter in bypass.
wemay
Site Donor 2023
I do.
I give it 30 seconds thats it. It takes me that long to get settled and do a sanitation wipe down each day.
Only time I wait more than 10 seconds is if the windows are foggy. Otherwise, start it, adjust radio, buckle in, and then go.
Originally Posted by TXCarGeek
I'm unsure what prompted me to do this, but do any of y'all wait for the RPMs to settle after a cold start before shifting into gear?
What's the precise reason for the higher revs to begin with? And is it at all beneficial to allow the engine to settle down like I have a tendency of doing?
You can decide which is best by your situation as I have done. Outside air temps? or in the garage as cold start ? Auto or manual trans etc....
Here's what I mean;
With the cars we have now, I don't really make a conscious decision to wait. My Madza CX-9 is garaged and I honestly don't look at the tach to see what it's cold start behavior is. By default though, I can tell you it does not jolt or slam into gear because I'd know it and would most definitively make a conscious decision to wait. That kind of drama on an automatic trans and drivetrain isn't ideal.
On my VW that sits out all winter, the cold starts are the same, no jolt as I put the car in gear to drive away. I mention the garage only because it might make a difference on some cars or older one's with carburetors. A garage temp of 40 f and an outside overnight temp in the mid 20's could make a difference in how high the revs are at the time you cold start it.
My Infinity was a 6MT and as others mentioned, with a manual transmission, you can engage the drivetrain without the slam of an automatic because you are manually searching the grab threshold and won't cause an abrupt friction point. The G35 I had would cold start outside in winter and rest at 1100 - 1200 rpms for a minute or so, drop to about 850 then drop to 650 or 700 or the normal rpms when warmed up. Carbureted motors had a mechanical means of dropping to normal from the 'fast idle' and these newer designs are electronic monitored and controlled.
With the older set up, I believe the fast idle speed was a means to warm up the car a bit faster and the fuel/air mix was a bit more finicky with mechanical controls and adjustments.
With newer cars an regulations, it's all done by computer and emission regulations (apparently) have proven faster warm-up is better for meeting standards.
I'm unsure what prompted me to do this, but do any of y'all wait for the RPMs to settle after a cold start before shifting into gear?
What's the precise reason for the higher revs to begin with? And is it at all beneficial to allow the engine to settle down like I have a tendency of doing?
You can decide which is best by your situation as I have done. Outside air temps? or in the garage as cold start ? Auto or manual trans etc....
Here's what I mean;
With the cars we have now, I don't really make a conscious decision to wait. My Madza CX-9 is garaged and I honestly don't look at the tach to see what it's cold start behavior is. By default though, I can tell you it does not jolt or slam into gear because I'd know it and would most definitively make a conscious decision to wait. That kind of drama on an automatic trans and drivetrain isn't ideal.
On my VW that sits out all winter, the cold starts are the same, no jolt as I put the car in gear to drive away. I mention the garage only because it might make a difference on some cars or older one's with carburetors. A garage temp of 40 f and an outside overnight temp in the mid 20's could make a difference in how high the revs are at the time you cold start it.
My Infinity was a 6MT and as others mentioned, with a manual transmission, you can engage the drivetrain without the slam of an automatic because you are manually searching the grab threshold and won't cause an abrupt friction point. The G35 I had would cold start outside in winter and rest at 1100 - 1200 rpms for a minute or so, drop to about 850 then drop to 650 or 700 or the normal rpms when warmed up. Carbureted motors had a mechanical means of dropping to normal from the 'fast idle' and these newer designs are electronic monitored and controlled.
With the older set up, I believe the fast idle speed was a means to warm up the car a bit faster and the fuel/air mix was a bit more finicky with mechanical controls and adjustments.
With newer cars an regulations, it's all done by computer and emission regulations (apparently) have proven faster warm-up is better for meeting standards.
Last edited:
Originally Posted by bachman
Originally Posted by TXCarGeek
I'm unsure what prompted me to do this, but do any of y'all wait for the RPMs to settle after a cold start before shifting into gear?
What's the precise reason for the higher revs to begin with? And is it at all beneficial to allow the engine to settle down like I have a tendency of doing?
You can decide which is best by your situation as I have done. Outside air temps? or in the garage as cold start ? Auto or manual trans etc....
The high idle lasts longer when it's colder, but today I started my 550i after it was sitting for two days and it high idled for about 15 seconds with ambient temps in the low 90s. Took me about that long to get settled in anyway.
Originally Posted by TXCarGeek
I'm unsure what prompted me to do this, but do any of y'all wait for the RPMs to settle after a cold start before shifting into gear?
What's the precise reason for the higher revs to begin with? And is it at all beneficial to allow the engine to settle down like I have a tendency of doing?
You can decide which is best by your situation as I have done. Outside air temps? or in the garage as cold start ? Auto or manual trans etc....
The high idle lasts longer when it's colder, but today I started my 550i after it was sitting for two days and it high idled for about 15 seconds with ambient temps in the low 90s. Took me about that long to get settled in anyway.
Originally Posted by TXCarGeek
Doesn't seem like there's a consensus as to why modern vehicles cold start with a high idle for a few seconds.
I think it's worth noting that I'm not talking about letting your car idle for an extended period of time to bring it up to temp. Doing that has been thoroughly debunked as being useless and a waste of fuel with modern vehicles. I'm talking specifically about the few seconds after starting where the idle is higher than normal and eventually settles down to normal...
Modern cars use the higher idle and a rich fuel setting when cold to get the catalytic converters warmed up quicker.
Today's high idle is nothing compared to the old carburetor days when engines would scream on a cold start.
Doesn't seem like there's a consensus as to why modern vehicles cold start with a high idle for a few seconds.
I think it's worth noting that I'm not talking about letting your car idle for an extended period of time to bring it up to temp. Doing that has been thoroughly debunked as being useless and a waste of fuel with modern vehicles. I'm talking specifically about the few seconds after starting where the idle is higher than normal and eventually settles down to normal...
Modern cars use the higher idle and a rich fuel setting when cold to get the catalytic converters warmed up quicker.
Today's high idle is nothing compared to the old carburetor days when engines would scream on a cold start.
I wait until they get to about 1,000 rpm before taking off. I'd rather not slip a clutch with a high revving engine, or slam an automatic transmission into gear.
Originally Posted by demarpaint
I wait until they get to about 1,000 rpm before taking off. I'd rather not slip a clutch with a high revving engine, or slam an automatic transmission into gear.
I do this as well.
I wait until they get to about 1,000 rpm before taking off. I'd rather not slip a clutch with a high revving engine, or slam an automatic transmission into gear.
I do this as well.
I'm a <1000RPM guy and have been since I have been for over 30 years for the same reason demarpaint gave. Of the people I know who have had to replace engagement clutches, those are the ones that put their car into gear right away not giving any thought to RPM.
My Buick jumps up to around 1500rpm when it first starts but immediately drops to 1100ish and them over the next couple minutes slowly drops, at that time I engage the tranny usually around 900ish. There have been a few times I've been in a hurry and take off right away but it doesn't seem to have any adverse affect, no jerking or banging.
I wonder if he high rpm on start up has to do with getting oil going, I can imagine in my mind the pump spinning faster and pumping more oil in that small time frame but of course that's just a guess.
I wonder if he high rpm on start up has to do with getting oil going, I can imagine in my mind the pump spinning faster and pumping more oil in that small time frame but of course that's just a guess.
Originally Posted by Duffyjr
My Buick jumps up to around 1500rpm when it first starts but immediately drops to 1100ish and them over the next couple minutes slowly drops, at that time I engage the tranny usually around 900ish. There have been a few times I've been in a hurry and take off right away but it doesn't seem to have any adverse affect, no jerking or banging.
I wonder if he high rpm on start up has to do with getting oil going, I can imagine in my mind the pump spinning faster and pumping more oil in that small time frame but of course that's just a guess.
The high rpm on cold start is for emissions and getting the cat up to temp and into closed loop faster.
My Buick jumps up to around 1500rpm when it first starts but immediately drops to 1100ish and them over the next couple minutes slowly drops, at that time I engage the tranny usually around 900ish. There have been a few times I've been in a hurry and take off right away but it doesn't seem to have any adverse affect, no jerking or banging.
I wonder if he high rpm on start up has to do with getting oil going, I can imagine in my mind the pump spinning faster and pumping more oil in that small time frame but of course that's just a guess.
The high rpm on cold start is for emissions and getting the cat up to temp and into closed loop faster.
I have always waited on a COLD engine for the thing to go closed loop, run on lambda control and do its system checks.
Seems to take about 20 sec when really cold on the vw.
it also starts with a high idle w/ a HOT engine , but I don't wait for the idle to drop on a hot, warmed up start.
Like others have said the engine seems to run better the rest of the commute if i treat it gingerly during warmup.
Seems to take about 20 sec when really cold on the vw.
it also starts with a high idle w/ a HOT engine , but I don't wait for the idle to drop on a hot, warmed up start.
Like others have said the engine seems to run better the rest of the commute if i treat it gingerly during warmup.
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