Ken,

Thanks for the idea.  Tried a new ECU; no change.  Still idles high.

tabe

--- Ken Wilford <kenwilfy@comcast.net> wrote:

> I had a customers van here not too long ago with idling issues.  Of
> course you need to check your grounds and the throttle position switch
> first to see if these could be bad or out of adjustment.  If they are
> fine then I usually swap over the idle computer from a good running
> van.  If that doesn't work I swap over the valve on top of the engine.
> Still bad?  I was scratching my head on this one, then I just tried
> swapping over the engine ECU.  Idle went back to normal.  Apparently
> something in the Engine Control Unit itself (under the back seat) was
> causing the idle problem.  Just an idea.  I have all of these parts to
> swap around so it makes it easier for me to test for these problems.
> You could try swapping in an ECU from a good running van from 86-91
> (they will all work) and see what happens.  I have rebuilt units with a
> one year warranty for $250 if you find you need one.
>
> Just FYI:  The factory 2.1l ECUs had problems with three things.  They
> decided to integrate the ignition module into the ECU so it got hotter
> than the older ones with the separate ICM.  Then they stuck it under the
> rear seat where it gets no air flow.  Then who ever was building the
> boards decided to do a crappy solder job on several of the connections
> (cold solder joints).  Murphy's law was in full effect that day!
>
> Hope this helps,
> Ken Wilford
> John 3:16
> www.vanagain.com
>
> Tabe Johnson wrote:
>
> >To recap:  Both my engine and that of Larry Himli (both 2.1s)
> >idle around 2400-3000 rpm.  In my case, it used to be that it
> >would just do that till it got warm, then it would idle properly,
> >and sometimes pop up to idle at 2400-3000 rpm.  Now it does
> >it all the time.  I swapped out the idle computer.  No change.
> >My temporary  fix: Unplug the idle air bypass solenoid.  Engine
> >runs great otherwise.
> >
> >
> >Larry's AC thing is interesting -- it says that the idle computer
> >is at least trying...  I'm still wondering about the
> >computer.  There was a post a few years back about fixing damaged
> >computers by replacing a one transistor that always blew.
> >
> >The inputs and outputs are pretty simple.  I went through this
> >too, and heres what I came up with:
> >
> >IDLE COMPUTER INPUTS:
> >Idle Switch
> >PS Switch
> >AC Switch
> >Hall Generator
> >Temp sensor 2
> >Power from relay
> >
> >IDLE COMPUTER OUTPUTS:
> >Idle air bypass
> >
> >Ideas?  Anyone?  Beuller?
> >
> >
> >
> >tabe johnson / 87 westy
> >
> >--- Larry Himli <lhimli@msn.com> wrote:
> >
> >
> >
> >>Bummer, I was so sure the relay would fix it....but no luck.  It still revs
> >>up to about 2K and at least it oscillates back and forth.  I turned on the
> >>air conditioning and it really revved up.  So now we have to try something
> >>else.  Have you studied the wiring diagram?  I will try to look it over and
> >>see what might feed the relay, etc.  At least it isn't raining
> >>
> >>
> >
> >
> >
>