Re: Idle Speed Issues (cold start and all the time)

["Ron J" <ron@xxxxxxxxxxxxxxx>]

Sounds like the ICV to me.. Sometimes just carb cleaner doesnt do it, and
you have to get a brush and actually get rid of the deposits inside the
mechanism that you can see.

What you describe is very familiar, and I know that it took a few cleanings
of my ICV before it went away, and sometimes the symptoms return, and I have
to repeat the procedure..

One sure way of checking it is when the car starts to do the behaviour, is
to pop the hood and get a heavy object, like a wrench, and tap on the ICV
while the idle is surging, or sitting high, and if it settles, then you know
its the ICV.

I have to replace mine soon, but this is how i have been getting mine to
settle

Hope that helps

Cheers
Ron J
85 535i
73 911s 2.7
- ----- Original Message -----
From: <AHSprite78@domain.elided>
To: <bmw-digest@domain.elided>
Sent: Thursday, December 05, 2002 1:11 PM
Subject: Idle Speed Issues (cold start and all the time)


> Initial problem: I'd been having some problems with excessive revs at
start up when the temperature starts to drop outside.  The car's probably at
about 20-45 degrees F when started, then revs to about 2500rpm before
gradually dropping slowly.  After about 20 seconds the engine begins to rev
from 1500 to 2500 or so, just like stabbing the throttle.  Then it will drop
down to normal idle (800 or so rpm) after a few revs.
>
> So, I was thinking it was the ICV so I used a can of carb cleaner and
sprayed it down the tube connecting to the throttle body/intake boot to the
ICV.
>
> Results: No luck.  Cold start still revs to about 2500rpm but hasn't reved
up and down after 4 cold starts.
>
> New problem now.  The car doesn't immediatly idle at the prescribed 800rpm
or so.  If the car is removed from gear and left in neutral while under way
it will drop to 1000rpm, rev to 1500 and then settle in at 1000 and stay
there indefinely.  When you come to a stop, same issue except if allowed to
sit for 5 seconds or so it will idle at 800rpm.  Doesn't seem to matter if
it's in gear, clutch in or out, brake pedal pushed.
>
> Anybody have any ideas on this one?
>
> My thought was the ICV is bad so it needs replacing.  Second thought was
that the throttle plate is not sealing properly.
>
> Not sure if this is related but under light acceleration, when shifting
gears no matter how long you've been off the gas before clutching in, then
engine revs once the clutch is depressed.
>
> Thanks to all who read this and even greater thanks to those with ideas.
>
> Matthew C Smith
> '96 BMW 328is
> www.rose-hulman.edu/~smithm3
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