If you change out the ISV or the ISCU, be sure you set the idle speed
before hooking it all back up. Just warm the engine, disconnect the idle
stabilizer valve (ISV) and adjust the big slotted screw near the contol
on the air intake system until the rpm reads 850-900 rpm. Then shut it
off, and reconnect the ISV. Let the engine get cold, then restart. The
ISV should hum(vibrate) and the rpm should read just slightly above 1000
rpm until the eninge warms up. At that point the ISV is cut out of the
circuit.  Once the engine is warm, turn on the AC. The engine rpm should
increase when the ISV kicks in to keep the engine from stalling under
the AC load. Turn off the AC, and then turn the steering to the stops
each way. The power steering switch should kick the Idle Satbilizer
system on and boost the RPM to prevent the PS pump from overloading the
engine and stalling it out.

Good Luck.

John Rodgers
88 GL driver

Richard Golen wrote:

> Hi,
>
> Just when I think I've solved the bad idle problem in my 87, it
> developed a
> new behavior. I swapped out the idle stabilizer with my wife's 90
> cabriolet. The rough idle/rich mixture problem at start up seemed to go
> away. But then after a day or so, it would idle at 2000 and stay there. I
> shut off the key and quickly turn it back on and the idle would drop to
> normal, but eventually get back to 2000.
>
> So I out the original idle stabilizer back in the 87...but before doing
> that I cleaned it with carb cleaner as suggested by someone on the list.
> The 87 ran ok for a few minutes then after I drove it around the block a
> couple of times, the idle went back to 2000.
>
> I've noticed that the stabilizer constantly "hums". Is it supposed to
> shut
> off after a while?? I disconnected the stabilizer and opened up the air
> bleed screw on the throttle body, and it seems to idle ok now.
>
> This is getting frustrating!!
>
> I also cleaned the ground connections for the oxy sensor in hopes that
> would help....
>
>
> TIA
>
>
> Ric
>