[Shotimes] Re: Idle Speed Controller Question

[Leigh Smith]

Carl;
Just got your e-mail tonite????
If EATC was off, it can't be the A/C.
Yes, run both the KOEO and KOER tests.
One of them specifically checks the IAB for shorts, the other for rpm
results.
There is a code and it should throw it if it is bad enough.
I do believe others have found IABs that stick, and they may not throw a
code.
I would definately try cleaning out the engine side with carb cleaner.
The electrical side you could check with an ohmeter.
Only other possibilities I can imagine for sporadic idle would be vacuum
leaks, (gaskets  hoses or tanks), dirty MAF, loose connector, bad TPS, etc.
Anyone else got any more ideas?
Lee
PS:
Pobst book tests ISC / IAB this way:
10.5 V at connector, Eng off.
varying from 3 to 11.5 volts as you vary engine rpm.
7 to 13 ohms eng off.
unplug & eng stalls.

Good luck!

----- Original Message ----- 
From: "Carl Prochilo" <GR8SHO@adelphia.net>
To: <leighsm@comcast.net>
Cc: <shotimes@autox.team.net>; <TechSHO@topica.com>
Sent: Monday, January 17, 2005 5:33 PM
Subject: Re: [Shotimes] Re: Idle Speed Controller Question


> The EATC was in the OFF position during this time.
>
> You are saying I should run the KOER test for the ISC, right?  I probably
just need to rip the intake off again and clean up that area better.  The
problem is that I already stripped a stud for one of the intake braces, so I
need to make sure I'm more careful and rested next time.
> ====
> Cheers,
> Carl Prochilo
> 1992 Ultra Red Crimson
>
> ---- Leigh Smith <leighsm@comcast.net> wrote:
> > Carl;
> > Also check to see if the AC compressor may be failing / binding up.
> > My 89 had an idle problem for 2 years that even a new ISC wouldn't help.
> > Sporadic unstable idle / even to the point of stalling.
> > Until the compressor blew and a new one fixed the idle problem.
> > Just turn the climate control head to OFF and see if the problem goes
away.
> > An ECM self-test should identify a sticking ISC, but not a compressor.
> > Lee
> > ----- Original Message ----- 
> > From: "Carl Prochilo" <gr8sho@prochilo.myserver.org>
> > To: <shotimes@autox.team.net>; <TechSHO@topica.com>
> > Sent: Monday, January 17, 2005 12:42 PM
> > Subject: Re: [Shotimes] Re: Idle Speed Controller Question
> >
> >
> > > Yes, IAB.  I was looking at Autozone website at the time.  Seems to
have a
> > > lot of different names.
> > >
> > > My car seems to struggle now to hold a steady idle.  It has been
> > > developing slowly over that past few months but not to the point of
> > > stalling (yet).  At this point the idle will drop down to 600
momentarily
> > > before it bops up, and the low oil pressure light will come on.  Part
of
> > > the problem was masked by the LPM since it bumps the idle up slightly,
and
> > > now I've removed the LPM from the PCM.
> > >
> > > I was hoping cleaning the intake would cure the problem, but in fact I
> > > neglected to clean the IAB while I had it off.  Is it just a matter of
> > > pulling the part and spraying Berryman's in there?  I already know
that
> > > the lower screw is going to be a problem, so I may just pull the
intake
> > > off again to do it.
> > > -- 
> > > Cheers,
> > > Carl Prochilo
> > > 92 Ultra Red Crimson
> > >
> > > On Mon, January 17, 2005 10:21 am, Donald Mallinson said:
> > > > Carl,
> > > >
> > > > You mean the Idle Air Bypass valve (IAB)?  I think that is
> > > > what it usually is called.
> > > >
> > > > Symptoms are the car dies when you come to a stop and put in
> > > > the clutch, especially after a highway run, like an exit
> > > > ramp with a stop sign.
> > > >
> > > > ATX cars can develope a nasty rattling sound although the
> > > > car will still idle, but not well.  Open the air cleaner and
> > > > the rattle will be LOUD and that is usually the IAB.
> > > >
> > > > It can be cleaned with good results, certainly Performance
> > > > Plus has been cleaning them on MTX cars since 1992 or so
> > > > with good results.  Takes a few minutes, and if it doesn't
> > > > work, then they replace it.
> > > >
> > > > I think the one on the ATX cars is different and usually it
> > > > gets replaced.
> > > >
> > > > Don Mallinson
> > > >
> > > > Carl Prochilo wrote:
> > > >> What are the symptoms of a failing ISC?
> > > >>
> > > >> Also, cleaning of the ISC is usually not considered to be
effective,
> > but
> > > >> the part is cheap enough to just replace.  True?
> > > >>
> > > >> The ISC in question is from said 92 and is original (214K miles).
> > > >> ====
> > > >> Cheers,
> > > >> Carl Prochilo
> > > >> 1992 Ultra Red Crimson
> > > _______________________________________________
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> > > Shotimes@autox.team.net
> > > http://www.team.net/mailman/listinfo/shotimes