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85' 318i has too FAST an Idle. 2500-3000 RPMS!!

8312 Views 4 Replies 4 Participants Last post by  hem1944
:mad: :cry: Hello, I got this 85' 318i that now has too FAST an Idle. 2500-3000 RPMS, a high, steady idle. It just started doing it last week.

It starts fine, idles OK, but once the car warms up the idle jumps way up!

I checked the linkage, & it has no intake leaks . . . . . just a high, steady idle.

I tried changing the Air Stabilizer off another BMW I have sitting around and still the same. Exactly! Now after I messed with it awhile, it seems it's high no matter what!

The Air Conditioner is turned off

Anyhow, does anyone have any ideas? I seen a post on idles that surge, but nothing on if its a high, steady idle.

Any ideas would be appreciated!!

[email protected]
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air/fuel mixture.

Fuel pressure?

oxygen sensor?
Think inside the box!!! The Glove Box!!!

My second and most beloved Bmw was a 1984 318i (Mach Turtle):angel: . Mach Turtle was hurting some time ago just as yours is now. I remember coming home with the engine revving and people looking at me wondering if I was trying to race them. I did some tracing and found that the bosch system has the air idler in the engine bay, but it is controlled by a little green (sometimes black-approx. 4"x3") box next to your ECU on the glove box ceiling. You can limp home by putting a rag in the air line from the MAF sensor to the idler and adjusting the throttle cable to bring the rpm's to some decent range. I didn't develop a good method for testing this but unplugging the stabilizer usually ended the revving so I went from there. I think you can find a replacement at bavarianauto or BMP for around $90. I hope this helps and good luck to you.

Samantha :thumbup:

:thumbup: RE: it is controlled by a little green (sometimes black-approx. 4"x3") box next to your ECU on the glove box ceiling.

Yep that fixed the problem!! Thank You Very Much!!!!! It's called the Idle Control Unit I think. . .

WoW! :thumbup: It Worked!
Little Green Box, just like you said!

I got the car a few years back, first BMW I ever had and now I'm a BMW fan. Somehow I like the way it handles.

I'm fixing it up for my son who just got over a Kidney Transplant at Stanford! He just turned 16 and he's a great kid and seems to like to work on cars. (When he's not playing games)

Best Wishes,
[email protected]

Thanx for all the help to everyone!
temporary high idle fix 85 318

get a piece of dowel rod size of inside diameter of idle air valve outlet hose. drill a 3/16 hole through it and insert it into hose and reattach to the idle air valve. you may have to try smaller or larger holes to get idle to 800 rpm.
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