Re: [SIG@M535i] <E28> 535i Hesitation yet again.. Advice?

["Ron J" <ron@xxxxxxxxxxxxxxx>]

Oh, forgot to also mention that aside from stalling at a light or when
letting off the throttle, the car ran fine, no hesitiation.

- ----- Original Message -----
From: "Ron J" <ron@domain.elided>
To: "M535i SIG" <sig@domain.elided>; "BMW" <bmw-digest@domain.elided>; "E28 Group"
<E28list@domain.elided>; "UUC-BMW" <bmwuucdigest@domain.elided>
Sent: Tuesday, April 08, 2003 6:24 PM
Subject: Re: [SIG@M535i] <E28> 535i Hesitation yet again.. Advice?


> Hi Russ,
>
> Would the throttle position switch being faulty and effecting the ICV
cause
> the problem of the car running that rough?
>
> Another thing I also forgot to mention was yesterday, and the day before
> while driving the car (warm) at a light when I let off the throttle, the
> rpms would fall to an almost stall point and then catch again, and then
> almost stall again, or would stall.  The car would start fine, but as soon
> as you stab the gas, the rpms would come back down and go below normal
idle
> and almost stall or definatley stall.  This happened everytime I got off
the
> gas.  Once the car was cold, and then restarted the problem would go away,
> and reappear as soon as the car was warm again.  I am thinking its
> connected, since this rough idle issue today also seems to be evident only
> when the car reaches operating temp.
>
> My question is still, would a stuck open ICV valve cause this problem? or
is
> it just an indicator of something else that is wrong and cuasing the rough
> idle problem.
>
> Thanks
> Ron J
> 85 535i
> ----- Original Message -----
> From: "russelc" <russelc@domain.elided>
> To: <>
> Sent: Tuesday, April 08, 2003 6:12 PM
> Subject: RE: [SIG@M535i] <E28> 535i Hesitation yet again.. Advice?
>
>
> > Um,
> > The only thing I can see is 2 things, from the history and what you've
> just
> > said.  If the ICV is open when the car is off the idle switch, then
check
> > the operation of the throttle position sensor.  From there, I'd suspect
> the
> > DME.  The ICV should never be open under any condition when the idle
> switch
> > is false.  No sensor that I know of will open the ICV when idle switch
is
> > false.
> >
> > RussC
> >
> >
> > > -----Original Message-----
> > > From: Ron J [mailto:ron@domain.elided]
> > > Sent: Tuesday, April 08, 2003 2:57 PM
> > > To: M535i SIG; BMW; E28 Group; UUC-BMW
> > > Subject: [SIG@M535i] <E28> 535i Hesitation yet again.. Advice?
> > >
> > >
> > > Hello All.,
> > >
> > > Well the saga awakens yet again.. On my way to university to
> > > study at the
> > > library for an exam tommorrow, the car started to hesitate
> > > mildly at first
> > > and then more violently until there was no power at all,
> > > unless you put your
> > > foot all the way to the floor.  Then the tires would spin,
> > > and as soon as
> > > the RPMs settled it would hesitate again, and drop to about
> > > 500 or so.  I
> > > pulled off the road, and looked under the hood, and could
> > > find nothing the
> > > matter.  The engine was idling really rough, and eventually
> > > stalled while I
> > > was looking under the hood.  I kept tinkering and when I
> > > tried to start the
> > > engine again, I had a dead battery.  Luckily I there was a
> > > guy across the
> > > street with a van that gave me a boost.  I got the car
> > > started and limped it
> > > over to a garage.  The owner seemed to know the cars very
> > > well, and started
> > > to look under the hood.  he said it was a vacuum leak by the
> > > sounds of the
> > > hesitation and seemed pretty sure about that.  Anyhow, we
> > > tested the battery
> > > and I ended up getting a new one.
> > >
> > > By this time, the car was cool, and it started ok, and idled
> > > ok, but as soon
> > > as it got warm again, it started the rough idle.  We checked
> > > all the hoses
> > > and didnt seem to find a vacuum leak.  He then pulled off the
> > > (brand new as
> > > of January) ICV valve, and said it wasnt working properly.
> > > He did a test by
> > > looking on the inside of the valve while he had another tech
> > > turn the key
> > > from off position to on, without starting the car.  The
> > > little gate on the
> > > inside stayed open the whole time.  The valve buzzed but the
> > > gate never
> > > closed.  It would budge just a little but stay in the same
> > > position.  Since
> > > the valve was new, he said that it could be the computer, or
> > > one of the
> > > sensors near the front of the engine by the coolant intake.
> > > Apparently they
> > > signal the valve to open/close.
> > >
> > > As a side note, the hose running from the bellows to the
> > > valve cover (1"
> > > diameter) with a smaller 1/4 line running off the bottom was
> > > cracked.  It
> > > has electrical tape on it, and it wasnt leaking, based on
> > > what I could see,
> > > and what the tech said.  I am going to replace it anyway.
> > >
> > > He wanted to keep the car overnight and look at it tommorrow,
> > > but I said I
> > > needed it for exams tommorrow at university, so he said to bring it in
> > > afterwards.  He was going to check the signal to the ICV, and from the
> > > sensors.  I said I would bring the car back.  I left, and
> > > about 5 minutes
> > > away from the shop the car started the same behaviour again,
> > > and the exhaust
> > > got so hot, the rear rubber hanger caught on fire again.. I
> > > guess it was all
> > > that unspent feul in the tubes.  I put the hanger out, and
> > > now the car is
> > > parked.  I cant get to my exams tommorrow, and I dont want to
> > > try driving it
> > > to the shop again.  I guess it will have to be towed in.
> > >
> > > Any suggestions as to what might be causing this?  New ICV,
> > > new FPR (2nd
> > > one. purchased from the dealer this time)  New Cap and Rotor, new feul
> > > filter, new plugs, valve adjustment, and no visible vacuum
> > > leaks.  Could the
> > > ICV be causing this bad running condition?
> > >
> > > Please help
> > >
> > > Thanks
> > > Ron J
> > > 85 535i

------------------------------