ISV-voltage

[Ero Rademer]

Jukka Majanen wrote:
>> 
Can somebody please tell me the ISV-servo (´87 2.0)
voltage working area. Just found only 1.6V, seems
to open, but the logic is wrong, opens when warm?
<<

Hi!

I had a'87 2.0 engine (KP) and have been into the ISV quiet
deeply. It is not controlled by voltage rather than by 12V
pulse-width. If you measure 1.6V with a normal DC volt-meter,
this might mean about 1/8 open. The ISV is supposed to be
(a little) open when the engine is warm to stabilize idle.
If you turn on the AC, or switch on a big electrical load
the idle is adjusted accordingly. When the engine is cold, 
the ISV has to open more to hold idle. If it's *very* cold
it increases idle significantly. Additionally the ISV
behaves different if you step on the pedal or not.

Checking with a 9V battery is fine, the ISV must open fully.
Putting 12V DC to it for longer periods might fry the ISV.

Don't forget: The control module does not drive the ISV after
you pull the plug to the ISV or the temp sensor (or the ISV is
toast) until you switch off iginition. So the question is:
how did you measure the 1.6volts? While connected or while off?

HTH!
Ero.
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