Rough Idle when cold, Fine when warm

[Wem0221]

Got a 1995 525i and whgen i start it in cool mornings it idles rough till warms up then idles and runs perfect, If it is a 90 degree day out it starts and runs fine and does idle rough at all...Anyone had this problem and may suggest a fix, I am a newbie to the beemer world....

[DonJ]

There is an air intake temperature sensor. on M50 and M60 engines. It senses the air temp in the intake manifold. The signal is used for adjusting fuel injection and ignition timing. I'm just guessing if it could be the problem but it might be a good place to start.

You can Google air intake sensor 1995 525i and see if there's any technical info about it.

The Bentley manual has info on how to test it. Doesn't look like an expensive part to change if thats the case.

[BimmerE39]

I had this problem with my 528i (2000/M52TU) before. It was my crank case vent valve. On cold days the valve would open all the way and cause a massive vaccuum leak. I even had the car stall on a few occasions because of it. It is a common problem with these cars and I would also get your ICV cleaned while you're at it.

[Wem0221]

Thanks I am out of town and will let that be my start to see if that may be my problem