Gaskets for ISC?

[Azplinker]

I'm having problems with my idle speed. It races to 2.5 K at cold, then drops to 600 - 700 rpms at hot. If I find out the Idle Speed Control (ISC) needs to be cleaned, where do I find replacement gaskets?

[fixkick]

welcome
16v
2500 is tad high, but not in Alaska, i've tested the IAC in a cold refrigerator. and ice box,

down to -10F (minus) and it goes wider colder. so idle speed is not limited at -10f at all ,
my point is 2500 is possible, easy if real cold and id need to know how cold your's was? at 2500, (my guess, night time temps,. and at 6am first start?)

ok 700 is illegal hot RPM if it really is hot , 180F or more? 750 to 850rpm is spec. hot rpm and is regulated.
is 700 in park or drive
this engine will hold hot RPM to 800 even shifting from Park to drive.
does it?

that is the best dynamic hot rpm check with in 3 or 4speed.

also
check engine light on key on
the out running?

cheers !

I'm having problems with my idle speed. It races to 2.5 K at cold, then drops to 600 - 700 rpms at hot. If I find out the Idle Speed Control (ISC) needs to be cleaned, where do I find replacement gaskets?

[fixkick]

i cut my own
from raw stock and and exacto knife
napa stores sells flat gasket stock.

precut, not sure...

felpro sales others.

[Azplinker]

Update: I had fixed an air leak in the air intake hose at an earlier time. I believe that caused a host of issues from no power during acceleration to limp mode after several miles of driving. Also had a cracked exhaust manifold which kept vehicle from running for several months. During removal of exhaust manifold, I found the intake hose leak in the folds of the bellows.
Now that I think the air leaks are mostly fixed, the ISC when hot will not hold idle. In fact, when the engine is hot and switched off , it won't start or run unless given some throttle.
I've been advised to run seaf**m into the intake to clean stuff out but hesitate in case even more problems are caused by this treatment. I am going to try your trouble shooting methods of testing the resistance of the coil and maybe removing and trying to clean the ISC.

Should I put RTV on the gasket when I put it back together since it has to seal coolant as well as air?
What is the torque for the ISC bolts?

[fixkick]

yes the air hoses are old and most have cracked , and messes up MAF readings big time.

well the IAC needs to work cold. but your having hot start problems. IAC is closed hot.
seafoam is no cure, but the gunk under the throttle valve , will not stop starts, its closed 100% ,until you step on the throttle.
what works is clean parts by hand, no magic to that. and is hard work,.
the iSC must be free to work, or hot starts will be very difficult, lacking fresh metered air.
sure id use sealant, there are many kinds, most work. ok
6mm bolts are all about 89 inch/lbs torque, (inch not feet) divide by 12 to get feet.

get ISC freed up set duty cycle hot, and it now idles all day at 800rpm
the TPS idle switch must be closed, and 0v or the ISC is born dead.

the isc is open at 12v and closed at 0v.
the video you can hear the snappy clunks. (it can leak a tiny bit closed, no problems, most do this old)

http://www.fixkick.com/videos/FLV-all/showtime.html#ISC

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isc is easy to work with
IAC a big pain, so if its closed hot, and open cold, its ok, just leave it be...

[Azplinker]

yes the air hoses are old and most have cracked , and messes up MAF readings big time.

well the IAC needs to work cold. but your having hot start problems. IAC is closed hot.
seafoam is no cure, but the gunk under the throttle valve , will not stop starts, its closed 100% ,until you step on the throttle.
what works is clean parts by hand, no magic to that. and is hard work,.
the iSC must be free to work, or hot starts will be very difficult, lacking fresh metered air.
sure id use sealant, there are many kinds, most work. ok
6mm bolts are all about 89 inch/lbs torque, (inch not feet) divide by 12 to get feet.

get ISC freed up set duty cycle hot, and it now idles all day at 800rpm
the TPS idle switch must be closed, and 0v or the ISC is born dead.

the isc is open at 12v and closed at 0v.

(it can leak a tiny bit closed, no problems, most do this old)

http://www.fixkick.com/videos/FLV-all/showtime.html#ISC

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isc is easy to work with
the video you can hear the snappy clunks.
IAC a big pain, so if its closed hot, and open cold, its ok, just leave it be...

Did not remove ISC due to on car testing. Activated the ISC solenoid with 12V. Blocked blown air in until 12V applied then opened with a "Click". Tried several times without the ISC sticking or anything. Did not seem to leak air when first blowing on hose to 0V on ISC. Guess I need to back probe electrical connections to see if ECU is turning on the ISC during running engine time.

Update:
Back probed ISC and checked to make sure it had voltage present. Ran up to hot temp and watched voltage on DC meter vary from 2.6V to 5.4V depending on bleed screw setting and RPMs. Higher RPMs = lower voltage. Don't have scope or duty cycle meter.

[fixkick]

the IAC closes at 150F water temp
and IAC flows zero air now and up to 180f+, (if it leaks hot RPM screams hot)
at this moment the engine idles off the bleed and ISC flows hot, (there are no other air supplies... on working system)

rpm of 650 means the ISC is not working, (or list below) (could be it cant handle, gross rich misfiring or lean bogging )
the ECU sets idle at 800 +-50rpm (coded) 650 is wrong , means engine is misfiring or ISC out of control.
and regulates there, hot, (p/s not overloaded or a/c not on, if on? then hot idle is 1000 rpm.

so the duty can be checked with some meters, on DC volts.
and 7v is 50% if that meter works right, most cheap meters don't, but fast meters do , if it can average a 200 hz square wave, and average 0v and 14v to 7v. (50% point) (set to 20vdc scale)
the bleeds screws purpose is not to set rpm, but to put he ISC in its center of authority, once there, idle servo code, wakes up and regulates to 800.
eg; The ISC might raise RPM 400 or lower it, by same,
for example putting the auto stick in drive from park the ecu opens the ISC real wide, to handle that load.

low rpm 650 is caused by
1: egr leaking
2: engine misfire, egr leaks is misfire too. i can hear your engine, so cant hear misfire, and would if it was present.
3: isc dead.
4: throttle tps idle switch stuck open, no 0vdc


if engine runs good on hills its not a CAT melted so, scratch that off list.

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16v can also lower RPM out of control for
lean AFR
if the maf is dirty at idle, and say 02 sensor dead.
the AFR goes lean and idle can drop, (ECU tries to prevent it with ISC actions)
or
if you have any air leaks at all from the MAF to the throttle body, same deal or any vacuum leaks at all , it goes lean.
keep in mind the 02 servo (closed loop) works hard to cure lean.
but may not, for 2 reasons
02 dead
or the leak is extreme.
all vacuum lines on engine are suspect.

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my 97 had a metal intake top huge pipe.
the mount at the rear was missing a bolt.
and it beat the pipe mount to death cause the alum, mount to break off and huge hole in the pipe, sucking air like mad. or those silly plastic induction pipes crack at the accordion sections.
all induction paths and hoses must be leak free on all MAF engines. MPI.
all leaks are called un-metered air, and are all bad news.

[fixkick]

getting the G16b air tight is no picnic.
lots of places to leak air,(vac, leaks)
and can add up. to huge leaks.

in fact the PCM tries to hide the leaks until, they just add to , too much.