Cold Start RPM Spike?
01-19-10, 07:08 PM
#16
Pole Position
All of these numbers and times are going to be different depending on how cold the engine/outside temperature is, whether or not you sit there letting it idle or start driving, and how you drive.
It's going to idle higher longer the colder it is. I wouldn't worry about it unless your fully warmed up idle is far off from 600 or jumps around a lot after that point.
That guy in Siberia has his idle at 4800 rpm for half an hour.
Remember this is the car trying to prepare itself for operation, when the fluids are cold in your car they are like thick sludges. They say that with modern cars "warming" up the engine isn't necessary, blah blah blah, but I still like to at least let it get it's first little fit out of the way and settle in around 1000 before driving off.
It's going to idle higher longer the colder it is. I wouldn't worry about it unless your fully warmed up idle is far off from 600 or jumps around a lot after that point.
That guy in Siberia has his idle at 4800 rpm for half an hour.
Remember this is the car trying to prepare itself for operation, when the fluids are cold in your car they are like thick sludges. They say that with modern cars "warming" up the engine isn't necessary, blah blah blah, but I still like to at least let it get it's first little fit out of the way and settle in around 1000 before driving off.
01-19-10, 07:22 PM
#18
All of these numbers and times are going to be different depending on how cold the engine/outside temperature is, whether or not you sit there letting it idle or start driving, and how you drive.
It's going to idle higher longer the colder it is. I wouldn't worry about it unless your fully warmed up idle is far off from 600 or jumps around a lot after that point.
That guy in Siberia has his idle at 4800 rpm for half an hour.
Remember this is the car trying to prepare itself for operation, when the fluids are cold in your car they are like thick sludges. They say that with modern cars "warming" up the engine isn't necessary, blah blah blah, but I still like to at least let it get it's first little fit out of the way and settle in around 1000 before driving off.
It's going to idle higher longer the colder it is. I wouldn't worry about it unless your fully warmed up idle is far off from 600 or jumps around a lot after that point.
That guy in Siberia has his idle at 4800 rpm for half an hour.
Remember this is the car trying to prepare itself for operation, when the fluids are cold in your car they are like thick sludges. They say that with modern cars "warming" up the engine isn't necessary, blah blah blah, but I still like to at least let it get it's first little fit out of the way and settle in around 1000 before driving off.
01-19-10, 07:32 PM
#19
Pole Position
I can only guess at what the car is "thinking" when this happens, but perhaps it takes a little while to judge just how cold things are taking into account the air temperature as well. We need a toyota/lexus master tech on this forum to satisfy our curiosities.
In my case, it doesn't only just spike up, but it seems to reciprocate between the higher and lower rpms on the high range until it settles in sometimes.
01-19-10, 07:45 PM
#20
Funny that you say that. I used to be a Toyota Master about 8 years ago and switched professions since. I still know a ton of them but don't know any lexus guys. I'll hit up one if my old co-workers who still wrenches and see what he says.
These cars have changed so much since I wrenched. Typically air temp really has no affect on idle speed. It's mostly done by coolant temp. Well, at least it used to.
These cars have changed so much since I wrenched. Typically air temp really has no affect on idle speed. It's mostly done by coolant temp. Well, at least it used to.
01-19-10, 08:04 PM
#21
Pole Position
Funny that you say that. I used to be a Toyota Master about 8 years ago and switched professions since. I still know a ton of them but don't know any lexus guys. I'll hit up one if my old co-workers who still wrenches and see what he says.
These cars have changed so much since I wrenched. Typically air temp really has no affect on idle speed. It's mostly done by coolant temp. Well, at least it used to.
These cars have changed so much since I wrenched. Typically air temp really has no affect on idle speed. It's mostly done by coolant temp. Well, at least it used to.
I guess it's a mystery for now.
01-19-10, 10:07 PM
#23
You're probably right, it was just a shot in the dark. I've never wrenched for a living (I'm a software developer, not typically what people think of when they hear about somebody using hand tools) but I've done a lot of my own work on past crappy cars, and pretty much disassembled and reassembled my motorcycle on a couple of occasions (that thing has made me a lot less mod hungry, I think I got it all out of my system and realized just how much money I wasted!).
I guess it's a mystery for now.
I guess it's a mystery for now.
01-20-10, 05:15 AM
#25
Send some of that cold my way and I will send you some Chicago Style Cold
My car does this when its cold but doesnt do any kind of 2nd jump. I would say its maybe 1500 at most and it drops as it warms up like any newer car. When fully warm my car has always idled around 600.
01-20-10, 06:09 AM
#28
Pole Position
47 Degrees is like a nice spring morning.
01-20-10, 09:19 AM
#29
Did you say cold Send some of that cold my way and I will send you some Chicago Style Cold
My car does this when its cold but doesnt do any kind of 2nd jump. I would say its maybe 1500 at most and it drops as it warms up like any newer car. When fully warm my car has always idled around 600.
Send some of that cold my way and I will send you some Chicago Style Cold My car does this when its cold but doesnt do any kind of 2nd jump. I would say its maybe 1500 at most and it drops as it warms up like any newer car. When fully warm my car has always idled around 600.
01-20-10, 09:28 AM
#30
Pole Position
I love my city, but I do envy your winters sometimes. Our summers can get nearly as hot as yours, though.
The positive thing is that we have lots of fresh water, and don't get any earthquakes, hurricanes or really any other natural disasters apart from a good dumping of snow a few times a year. =)
The positive thing is that we have lots of fresh water, and don't get any earthquakes, hurricanes or really any other natural disasters apart from a good dumping of snow a few times a year. =)