ISC solenoid repair?

[fixkick]

Welcome ! NIKE.

Hello everyone on the forum. (My english is bad, I use google translate :/) OK

I recently bought a Sidekick 1989 years, EFI 8V. Of course, I immediately met with the problem of high idlle. (1200-1500RPM)
Since I'm an electrician by trade, and I will deal with reparation electronic assemblies European cars, I easily found the problem it caused high idlle - ICS solenoid. The problem arose in the gasket between the ISC solenoid and throttle body. Gasket is burned between the inlet and outlet sections. Considering that in my country almost impossible to find a new gasket, I handedly created a new one. After a visual inspection of the ISC solenoid I noticed that the solenoid valve (inside) do not seal it completely. (Does not close completely airflow inside) Also, in my country is almost impossible to find a new ISC solenoid so I am compelled to fix existing ones.
I am interested in the following:

- Does the ISC solenoid valve has to seal completely when no voltage, or a factory left a small gap for partial air flow when the valve is not active?
it is ok to leak a bit , most do.
the trick is to close the 89 rear throttle body idle stop screw so the ECU can gain back control of idle. (less air.)

- Did someone tried to dismantle existing ones for reparations?
just clean it and get it 99% closed. no power.
when it was newl, the idle would be like 500 rpm unpugged. so if it leaks to 600 rpm the ecu can still control idle. no problem.
what is bad is if you closed the ISC and the idle is 1500 hot, you have a huge air leak to the plenum (induction)

- Also, when the valve is in operation mode (the bright, cold starts, etc.) solenoid has a very strong sound work (strong klicking), while the expected increase in engine RPM does not happen, or happens very little. This now creates a reverse situation when the engine is cold, low RPM drop 300-400 RPM. When the engine warms up the normal RPM (800 RPM), but I have the impression that the ISC works no need to increase the RPM.

- Is it possible (by input wire) solenoid open for reparations? I noticed that for some trying, because underneath the rubber cover notices silicone sealant.

By the way, thanks to the author fixkick.com, because it helped me with a lot of useful information. I'm an electrician and I hope you'll help others on the forum in some situations.

Best regards from Bosnia and Herzegovina.
Nike

PS: watch out for the other center Throttle body gasket that cranks and sucks in, very bad.
PS2: yes, old ISC rattle badly. (it modulates at 200times a second)

91+ iSC has preload adjustments unlike the 89/90
http://www.fixkick.com/sensors/tests/IAC-exploded2w.jpg

89 idle controls
The vacuum dash pot device operates for 10 to 30 seconds at cold start. and retracts the rod 100%
then the IAC leaks air cold for fast idle until about 150F coolant temp point.
after that only 2 leaks of air, the ISC and the throttle plate.

i try blooking off the ISC holes, hot engine, to see what RPM I get. must be way below 800, id say 600 about.

if idle RPM is real high hot.
make sure throttle cables are slack never tight
unscrew stop screw for throttle , this lowers idle speed, so ISC can take over.
seen here,but is ok to adjust on 89/90 (ignore bleed ports here you dont have that)
http://www.fixkick.com/fresh-air/Slide_S...ge_11.html

if Dash pot device retracked.
IAC in base CLOSED.
http://www.fixkick.com/fresh-air/Slide_S...age_9.html
vacuum leaks. (anywhere cause this engine to race) and there are lots of leak points.

One more IAC test
http://www.fixkick.com/fresh-air/Slide_S...age_8.html


What i do is make sure i can stall the engine hot, buy blocking the ISC. if it races still, you do have leak.
if i can get the ISC to close and the ECU can use it ok, i then set the duty cycle of the iSC to 50%
using a scope or duty meter.
then 800 is no problem hot the ecu tries hard to hold 800 hot.