Hi all

My engine is not idling well when warming up. I know it is related with the
idle valve because it is not humming when the ignition is ON (motor not
running). I did a good reading of the list concerning the Idle Stabilizer
Control Unit (ISCU) and the Idle Valve (ISV). My bad idle is coming at least
from these devices.

SO
I opened up the ISCU enclosure and found the transistor overheated and the
56 ohms resistor overheated as well. I changed both composants:  the
transistor for a ECG185 and the resistor for a 51 ohms 2 watts. After all, I
realized that my old resistor was still good. Anyway!!! I Also try the ISV
with a 12Vdc source and the valve was opening and closing following the
12Vdc power On and Off. SO I could say my valve is working.

I put back the ISCU behind the tail light and connect the ISV to its proper
connector only. When I turned on the ignition key (motor not running),
SURPRISE the ISV was humming. I turned off the ignition key and put back the
ISV with the air hoses. I try it once again (twice) and the ISV was not
humming anymore.

Once again I removed the ISV and the ISCU. I though my transistor was burned
out again. Just in case, I did some quick connection on my bench panel to
get 12Vdc on the terminal 15 and 31 of the ISCU  and I connected the ISV to
the ISCU. The result : the ISV was humming very nicely. I also simulated the
power steering switch and the ISV was humming differently.

Finaly my question is (thank you for reading until here): Is there anything
in the logic of ECU or ISCU wich turn off the ISV. Or is the ISV should hum
forever as long as the ignition key is ON (motor not running)? Otherwise I
could have a loose connection in the ISV cable? Too dark now, I will
investigate it tomorrow.

Thank you

Germain