Did you adjust the idle speed screw on the AFM?

You seem to have covered everything else. I didn't see it mentioned on
your list.

Warm the engine - run it around the block.
When back home - disconnect the idle stabilizer valve wire on the end of
the valve.
Start the engine.
Turn the very large slotted screw on the AFM. Turn right or left and
watch the tach. Remember your start point when doing the adjustment. I
count the screw flats - 5 right, or 10 left or whatever.
When idle speed settles at 900 rpm you are good enough. Reconnect the
ISV wiring and you are good to go.
Allow the engine to get cold, Restart. The cold start should give you
about 1200 rpm, and after it warms up it should drop back to 900-1000
rpm for idle.

Regards,

John Rodgers
88 GL Driver

Tim Marciniak wrote:
> Has anyone had an idle stablization control valve that hummed as
> Bentley describes it should, but found that after replacing it their
> idle problems were solved?
>
> My van idles at 1200.  Runs fine, starts fine.  But I cannot get it
> to idle below 1200 rpm.   I have spent hours trying to figure this
> thing out.  Here's run down of what I've done.
>
> -complete ignition tuneup, plugs, plug wires, new distributor cap,
> checked timing
> -cleaned all ground connections and replaced all ground connectors
> -replaced temp sensor x2
> -found open circuit from temp 2 to terminal 10 of ECU.  I replaced
> this wire.  I thought I had all my problems solved when I found this
> and in fact it did fix a lot of my idle issues because prior to this
> fix I had even more driveability issues.
> -adjusted and checked throttle position switch
> -cleaned idle stabilzation control valve with carb cleaner and
> verified that its humming away.
> -cleaned throttle valve
> -new O2 sensor
> -checked fuel pressure--ok
> -no vacuum leaks
> -checked air intake system, verified that I had no false air issues
> -replaced idle stabilization control unit (this is the last thing I did)
> -passed state emission test two weeks ago
>
> Van runs smooth, no lumpy idle, no hesitation or surging issues, just
> idles high at 1200.  Only thing I can think that is left to do is
> replace the idle stabilization control valve on top of the engine.
>
> Tim
> 90 Multivan
>
>