Thurs. 2-14-13...I just installed a brand new ICS.
And dagnabit , it made no differnce.
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I wonder if my spare ECU and/or Mass air I tried have the same defect?
Man I'm chacing my tail and getting nowhere <img src="/forums/images/graemlins/angry.gif" alt="" />
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Guess I'll figure on looking for a 89 T.B,,Mass Air and an ECU and starting back at square one.
I really want to disect a T.B. and see what's inside it fer sur.

I have the same problem in my new 89. Do you also get a check engine light that comes on during constant driving, that will go off if you let up on the throttle?

Dave, try plugging that hole in the floor of the TB throttle bore that the book tells you not to get TB cleaner into. It feeds the isc passage and I think it also feeds the thermostatic fidle valve, so blocking it should kill the fast idle, and thus diagnose the bad fidle or isc. Then you could remove the isc and put a cork in the hole that the pintle fits into and see if it's the tstat fidle or the isc.

...I'm getting no engine check light and I get no codes.
I tried using rubber plugs in that hole and the hole the pintle goes in a couple senile weeks ago. Plugging the hole in the bottom of the throat killed the engine . I unscrewed the "needle valve" to get enough air to keep it running , and then played around putting the rubber corks in varius holes.
I gave up that day more confused than ever.
That is why I want to buy a "new" used T.B. so I can destroy the one I have getting the bottom off it , photo it's gut, and see fer sur it the wax pellet valve also effect air passage. It's obvious from the outside that the air flows from the throat hole down thru the bottom piece and over to the ICS passage,,,I'd just like to get a look inside there.
One thing I noticed is one of the hoses on the T.B. gets hotter than hell, making me think the valve inside is closing.
Thanks for all these sugestions,,I'm reqally pulling my hair out over this. <img src="/forums/images/graemlins/cheers.gif" alt="" />

I'm living in denial...that ICS doesn't do it all...that a non replacable wax pellet failure can make you need to buy a Whole T.B.
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I'm gonna start a thread to get help to search for a part number for the "Fast air control valve"...
And an add for a T.B. <img src="/forums/images/graemlins/frown.gif" alt="" />

Before I start a 89 TB rant ....Mr Krzy ... May I ask ... In all your work and testing has it been done with the TB on the motor ...OR ..........

Have you had the TB a part and looked at it that way ..?????

And ..Or ..Is your monty "sort of" hard to start ...? (just a little ...)

Captain Gear Box

Hazardous Toys inc

The vehicle runs quite well,,,at 1,800 to 2,000 rpm idle,,,real fun zipping around grocery store parking lot...
It has newish TPS and brand new ICS. I drive around town without putting my foot on the gas pedal.
It starts good.
I have swapped in (and out) a spare Mass Air and ECU which made no difference in idle.
I can't get the tiny screws loose that hold the bottom part off ,so I can look inside at that valve.
I'm no longer employed so have alot of time on my hands,,,my engine /TB is spotless inside and out ,,I stay quite board and polish things alot <img src="/forums/images/graemlins/lol.gif" alt="" />.

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haztoys,,,I should have never doubted you....
This afternoon I got onto to doing fasteddy's test and cleaning water passages.
After messing around awhile I started engine with the Big air duct hose removed,,,with mass air still plugged in.
It runs kinda rough BUT basicly idles around 700.
I disconnected battery each time I plugged or unplugged ICS and Mass Air.
So I install the main duct hose and run it . Remove and run it,,and repeated this a couple times.
With hose conected it's running 1,800 rpm.
Again, with hose out, 700 rpm.
My test of the mass air only test one part of it. The ultrasonic Karmen vortex part is tested with a ocillascope according to alldata. I can't do that.
I think you only get a mass sensor code on this primative MPI sys. if the mass is unplugged or totally burntout. You get no indication if it's innaccurate.
So now my thick skull is kinda starting to understand the Mass air sensor...and I'm pretty sure both my mass airs are bad.

haz, you out there????

took in in for a sniff test---it's burning as it should.
Shop had a spare Mitsu Massair sensor. We put it on and no improvement.
He did check of T.B. by blocking holes in varius combinations...
I his opinion---it's the water heated Air vavle.
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Now I'm thinking of making a mod. of a water valve off a jumk 89-94 . Drilling out and plugging holes. This will get me by till cold weather.
Anybody out there got a junk 89-94 3.0 TB there lookin to get shed of for my experiment????
It can be trashed,,I just need an uncracked bottom part.

<img src="/forums/images/graemlins/smile.gif" alt="" /> <img src="/forums/images/graemlins/smile.gif" alt="" /> <img src="/forums/images/graemlins/smile.gif" alt="" /> <img src="/forums/images/graemlins/smile.gif" alt="" /> <img src="/forums/images/graemlins/smile.gif" alt="" />
It's Fixed,,,for now. Eliminated it and it's water supply.
I took the Idle Air Control Valve off and cut a gasket that blocks the IACV passage into the upper T.B.
The ICS still has air passage and functions.
Truck runs good and has never idles so smooth.For years it has really never idled quite right as I had to keep idle screw cranked closed. THe IACV was partially working all that time, but I guess when I hit that bump on The Carrizo Plains in Oct. it must have knocked the last of the wax out of the valve.
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I took alot of pictures of the guts and passages of all the T.B. and IACV, and ICS.
I'd like to post those picture into it's owe thread to help others with what seems to be a common problem with these aging rigs.
(I gotta yet figure out how to post them here, petiful).
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Getting those phillips screws out was a real PITA , I had to end up propane heating them, p-blaster, and micro impacting.
I put the IACV in the freezer and then boiled it to see if anything moved. Nope , it's outta wax.
As soon as I can find a junk IACV I'll do a complete disassemble(with pics) of it and make a more permanant version of this "eliminator kit". Other than the freeze out plug , the interior parts are threaded into the aluminum body. Maybe the is a way to rebuild.