Cold weather idle ????

Yes I have searched...

I have a 2004 325i. I noticed that when the temperature drops below about 35 that my car idles at about 900 rpms. Completely steady... doesn't drop or surge... just a steady 900 rpm. As soon as the temperature warms up it will drop back down to the 600 range which is where it normally idles at. Doesn't matter how long I drive it or let it warm up... seems to be completely dependent on outside teperature. Is this normal? Or should I be concerned?

When it is cold, the car is supposed to idle a little high, but it should drop down to normal idle once the car starts to warm up. It sounds like your car is stuck in cold start mode when it gets near freezing.

So is there any solution for this? oesn't really bother me much except it uses a tad bit more gas and it's louder than normal.

Heh, my idle in drive and reverse is 500-550 for the past 3 months or so

My service engine soon light came on and it started doing what the OP described once the cold weather started... However, I only took it on short trips for about two weeks which I think was a factor because I took it today for a two hour drive and it seems to not be stuck in cold weather start mode. Once I check the codes I'll follow up and let you know if it had anything to do with it.

Originally Posted by devin_name

Yes I have searched...

I have a 2004 325i. I noticed that when the temperature drops below about 35 that my car idles at about 900 rpms. Completely steady... doesn't drop or surge... just a steady 900 rpm. As soon as the temperature warms up it will drop back down to the 600 range which is where it normally idles at. Doesn't matter how long I drive it or let it warm up... seems to be completely dependent on outside teperature. Is this normal? Or should I be concerned?

It's funny. I noticed that tonight as well. Car running @ 900RPM in the cold weather. However I did notice couple times that when you turn the heater off manually the RPM drops. No idea why?
You may want to see if yours does the same.

M


It definitely has to do with the cold weather. I have noticed the rpm aound 800-900 when cold. After the engines warmed up it drops to 600rpm.

Thanks for the input guys, only thing I noticed is like what davewiig said... longer drives like 30 minutes or more and it seems to drop back down to normal.

I just want to make a suggestion ... Last year I used to have idling issues, either it would randomly surge or dip a bit while sitting at a light in neutral (manual car), or when I start it cold, it would hesitate or generally not run great until it warmed a little more.

In performing some other maintenance (CCV), I was right by the DISA, throttle, and ICV. I ended up taking out and cleaning all three of those (i was just curious as to their condition.

THE idle control valve ......... it was so sooty I could not believe it. I could not even tell how it worked!!

Took half a can of throttle cleaner to get all the black carbon out .. I was amazed it was now a clean chrome silver color, and even rotated under its own weight!!!

After cleaning that (damn, did it need it) all my idle issues completely disappeared.

SO moral of the story ... next time you are replacing an intake boot, the DISA valve, etc... take out the ICV and clean it .I you never have before, and you have 70k or more on the car (Like I did) it will NEED the cleaning. no new parts required, just some tim. Whenever I hear idling issues this is what i suggest.

I have not done my VANOS yet but purchased the seals thinking it was the cause for my idling issues. Now they are sitting on a shelf because I am lazy

^ I have a new DISA and cleaned my ICV. New plugs, new spark plug boots, new fuel filter, nothing is working at all. I will unplug my MAF and see if not I'm getting a reflash

BTW, here is my ICV vid

Originally Posted by Solidjake

^ I have a new DISA and cleaned my ICV. New plugs, new spark plug boots, new fuel filter, nothing is working at all. I will unplug my MAF and see if not I'm getting a reflash

BTW, here is my ICV vid

great vid! I agree with your last statements.. 60k and above, CLEAN IT!! Yours was as filthy as mine. I drive the same year/model as you.

Anyway, so yeah if you have cleaned that valve , did a tune up lately (plugs?). If yes i would guess it has to be a vanos or sensor issue .... got any codes?

To the OP, have you cleaned the ICV yet?

Originally Posted by easyIsle

great vid! I agree with your last statements.. 60k and above, CLEAN IT!! Yours was as filthy as mine. I drive the same year/model as you.

Anyway, so yeah if you have cleaned that valve , did a tune up lately (plugs?). If yes i would guess it has to be a vanos or sensor issue .... got any codes?

To the OP, have you cleaned the ICV yet?

Thanks. My last code was about 2 months ago. Pre-cat O2 sensor, came up about 4 times and hasn't come back. New intake cam sensor as well.

I have not cleaned my ICV... but it's not throwing any codes. I really think it's temp related. It warmed up her ein Southern Oregon... about 37 during the day instead of 30. Just that little change and the car idles fine. Maybe I'm wrong... but once it warms up I'll tear things apart and start cleaning.

Originally Posted by Solidjake

Thanks. My last code was about 2 months ago. Pre-cat O2 sensor, came up about 4 times and hasn't come back. New intake cam sensor as well.

Did you happen to reprogram your ecu after you changed those camshaft sensors?

I just wanted to add, that I am having a similar problem. I have a 2004 325xi and when it's really cold out (lower than -5 C) it idles at around 900 while the heat is on. If I turn the heat off or lower the temperature to the lowest setting, the car idles at 550-600 again. I also just had an Inspection II done recently and after replacing a worn serpentine belt was given a clean bill of health. I would love to know what could be causing this. Thanks

Originally Posted by silverarrow330

Did you happen to reprogram your ecu after you changed those camshaft sensors?

Reprogram no. I just changed the sensor and the ecu adapted to the new one. New programming required.

Hey so OP is back with a similar question (idle issues) but on a different car... just picked up a second E46, an '01 325xi with about 155k miles on it from a friend. Thinking back to this post I pulled the ICV, DISA and throttle body to clean them out and make sure they were operating correctly and no leaks. Also checked entire car for any vacum leaks and replaced a couple hoses for the oil seperator. Also checked the plugs and replaced the VCG as well as installed a new battery. Now what is happening is that car starts fine (although cranks maybe a milisecond longer than my other car) and idles fairly normally... high at first then settles after about a minute at about 700-800 RPM. But, I'd say half the time when I tap the gas the RPMs drop and the car dies.

Original owner is a buddy of mine and never had this issue but the car sat for almost a year due to a broken drive shaft that he was too lazy to replace. Could this simply be a case of bad gas in the tank from sitting so long? I can hear the fuel pump prime when turning the ignition so doubt that's the issue and I also put in a quarter tank of Chevron 92 just in case. Any thoughts?

BTW, he was pretty obsesive about maintenance up until the drive shaft. Oil changes every 5000 miles using mobile one, all the services have been done, coolant system replaced. Not sure if fuel filter was ever done though. Which brings up a second question... is there any reason to pay the dealer for their fuel filter versus one from an auto parts store for a third the price?

WEll wish me luck guys... after researching on here decided to bite the bullet and order the fuel pump. Also will replace fuel filter.

Read the first 2 links below in my signature.,

If the fuel is over 1 year old, you will need to get this out of the fuel tank before it start to run as best it can.

Fuel filter from a sponsor here or possibly a local parts store should be fine.

Many parts store parts are OE type parts repackaged anyway. Mayle & Mann are typical suppliers as I recall?

Jfoj... some of your posts were what encouraged me to purchase the fuel pump and filter. Also read something about a bad engine wiring harness... wondering if this could be my issue. Guess if pump and filter don't work then harness or maybe cam position sensors.