View Full Version : Low idle - help plz

10-01-2005, 10:13 AM
For the last couple of days, my car's been idling real low <500 rpm's, and today, as I was driving in a parking lot, my car died at low speeds. I started her back up, with no problem, and she died again, and again, and again. It's friggin' embarrassing when you're sitting in a BMW and the bitch is giving you problems.
Anyways, i tapped the outside of the mass-air sensor, as well as other idle-related-looking-bullshit-things, with a screwdriver handle, and now seems to be ok (knock on wood.
Any ideas what might be causing this?
I think my system is a Motronic OR Motronic 1.1...it's a 1990 325iS.
Help please,

10-01-2005, 10:39 AM
vac leak :confused: spray some carb cleaner around your vac lines and intake manifold, if the idle drops more then you've found the leak

10-01-2005, 11:01 AM
Spray some intake cleaner in your idle control vavle.

Our cars use an AFM not Mass-air flow sensors. But ya, it could be that also.
But i'd try cleaning ur idle control vavle first.

Is it idl'ing very rough? like its not firing on all cylinders? or is it smooth but low?

Also was it raining or damp when this was happening? If your wires are bad, they will short when it gets moist out causing the car to not fire on all cylinders, and die.

10-01-2005, 02:41 PM
I don't think I have an idle control valve that's readily adjustable, like on an M10.

The idling is back to normal which is minorly rough, but fine otherwise.

I was thinking along the same lines as dampness etc..but it's been pretty dry the last two days so i don't think it's that.

I checked all the hoses for visibl leaks, and nothing.

Thanks for the help guys *th-up*

Hey Trevor, are you going to the e30 meet tomorrow?

Actually, here's a pic of my air intake system. The idle control screw is located under the round blue plug on the AFM. But I think some computer actually controls the idle instead...not sure.

10-02-2005, 01:02 AM
I don't think I have an idle control valve that's readily adjustable, like on an M10.

Hey Trevor, are you going to the e30 meet tomorrow?

Yes I'll be there, i will be late thou, I get off work at 5pm.

The Idle control vavle(ICV) Doesn't have adjustments.......but when it gets dirty inside, it doesn't work too well.

See pic.

10-02-2005, 08:35 AM
wicked, thanks. maybe when I tapped it, I loosened some dirt/debris on the inside, hopefully it's still working ok today.

10-14-2005, 07:52 PM
OK...the problem went away for a day, then the car just wouldn't turnover. i had the fuel pump replaced and a throttle position sensor :confused: replaced . NOW...when i cold-start the car (overnight @ ~ 10 deg) the idle is low...500 rpms, but when the engine warms up, the problem goes away...wtf?