Higher idle speed when engine is cold: normal?

[Pajamarama]

Hello --

In the morning, when I start my car I notice that it idles around 1200 - 1500 RPM. On the drive to work, if I stop at a long stop light it idles around 1000 RPM. By the time I get to work (30 min drive) and pull into the parking lot, it will idle at around 750 - 800 RPM.

Is this normal or is something wrong with my idle speed(s)? Thanks.

 

[Dakota1820]

pretty normal. shouldn't take that long to warm up though.

 

[Trav]

Quote:
1200 - 1500 RPM

Thats normal but not this long. Maybe a vacuum leak or sticky IAC motor.

 

[stephen9666]

It's fine. The computer causes the car to idle higher when it's cold. I believe this is to cause the car to warm up faster, so it will be at operating temp quicker.


Originally Posted By: Trav
Quote:
1200 - 1500 RPM

Thats normal but not this long. Maybe a vacuum leak or sticky IAC motor.


The OP didn't say it took 30 minutes for the idle to fall, just that it is at normal idle when gets to work after 30 minutes.

 

[Eddie]

My Mazda starts at ~ 2,000 and within 10-15 seconds drops to 1,000 or so and within 1-2 minutes drops to a normal 650 rpm. In my opinion, anything over one minute is too long.

 

[Pajamarama]

Originally Posted By: Trav
Quote:
1200 - 1500 RPM

Thats normal but not this long. Maybe a vacuum leak or sticky IAC motor.


OK. I will do more timing/testing of the idle speed to learn more.

How long should it take for the engine to "settle down" to a 750 - 800 RPM idle? 5 minutes? longer?

Also wanted to add: this is on a 97 Accord wagon with 165k miles.

 

[Bgallagher]

I wouldn't be concerned at all. pretty normal. Just lay off burning rubber for the first 5 minutes when you start it cold.

 

[Dakota1820]

how long does it take to get to operating temp . my saturn doesnt idle at it lowest point until its almost warmed up. if it takes 5-7 mins its fine if it takes 30 you have an issue

 

[Pajamarama]

Originally Posted By: chevyboy14
how long does it take to get to operating temp . my saturn doesnt idle at it lowest point until its almost warmed up. if it takes 5-7 mins its fine if it takes 30 you have an issue


I have noticed that this car does run rather cool. First 5 minutes of driving from a cold start the temp needle doesn't usually budge. It think it moves to the 1/3 mark by 10-15 minutes and then stays there -- never gets to 1/2.

I have suspected during some other investigation on another issue that maybe my thermostat is stuck open. Could this be a symptom?

 

[mechanicx]

It does sound like your thermostat is going bad.

 

[Lead Shoes]

Originally Posted By: Pajamarama
Originally Posted By: chevyboy14
how long does it take to get to operating temp . my saturn doesnt idle at it lowest point until its almost warmed up. if it takes 5-7 mins its fine if it takes 30 you have an issue


I have noticed that this car does run rather cool. First 5 minutes of driving from a cold start the temp needle doesn't usually budge. It think it moves to the 1/3 mark by 10-15 minutes and then stays there -- never gets to 1/2.

I have suspected during some other investigation on another issue that maybe my thermostat is stuck open. Could this be a symptom?


I would change out the stat with an OEM one, its about a 30min job on a f22 accord, then while you are there take apart the Idle air control valve and clean it with carb cleaner, my Honda did the same until I cleaned mine.

 

[zzyzzx]

A high cold idle is normal, for about a minute.

 

[Trav]

Quote:
I have suspected during some other investigation on another issue that maybe my thermostat is stuck open. Could this be a symptom?

Yes it sure could. 30 min in Atlanta in the summer is way too long. 5-7 min i would guess is about it in cold weather.

 

[Quattro Pete]

Originally Posted By: zzyzzx
A high cold idle is normal, for about a minute.

+1

 

[JHZR2]

You need to put an OBD II Scanner on it. Ill bet the heating element is geting lazy on the O2 sensor, so it is taking longer, though still in spec to go to closed loop.

My cars, all of various makes, all drop idle speed as they switch to closed loop. They slow right down at that point. The newest cars get there so fast that there is hardly any wait during normal warm ambient temperature startup.

 

[mechtech2]

Modern engines have a pretty fast cold idle [to get oil flowing and prevent stalls], but then settle down quickly to normal.
For your problem, vacuum leak is #1, and dirty TB and IAC valves are next.