1989 screamer

[fixkick]

Hey Jerry first time caller long time listener love your programs  haha. 

I have a assortment of rigs 20 or so 1998 and older. 

1989 8V automatic gold ecu
Motors 1989 with the integrated throttle body IAC no waterline. The motor was removed and reinstalled 
I started it up ran huge rpms 3500 and pushed for 4000rpm with cut outs occuring. 
Stopped it whenever it started hunting due to it being way above average for a kick. 
Seemed like it was runaway lean. 
Assuming vacuum leaks
Got a party smoke machine fogged intake WOT found a seeping pcv valve.
Nipple had broken off gross leak at the intake. 
Replaced pcv same scream. 
Duct taped the air snorkel closed 0 oxygen basically purrs like a kitten 1500rpm.
Must be breathing somewhere. (yes)

Tried using a propane torch unlit around the engine bay with no rpm changes 
All cables are slack with butterfly closed. 
Hard lined the dash pot to the intake to cause it to release full time 500 rpm shaved
Could the isc be pulling that kind of air?

Any tips or tricks to isolate this vac leak. 

Really appreciate any and all advice to make this purr like a kitten. 
I got tons of parts to swap in if required but id rather invest time confirming good parts technician style vs wasting time changing bits and never knowing if their viable in another rig. 

Thanks for your wealth of knowledge and website.

lost my post here,  not sure how.

for sure huge vacuum leak.

all vacuum hoses pinched to make sure  non leak air?

vacuum booster , hose removed and cork up close to prove its diaphragm is not cracked.

TV closed, fully , then later when car is runs right ,do idle duty cycle calibration,  800RPM  50% duty, or 7v across ISC wires.

see my slide show? TB slides,  page 37 to 47 , see 89/90 all ways to leak.

ISC valves not stuck open or connect wrong. or unplugged electrics to them. some default open so.....

ECU idle up pin at the false logic, statE (Voltage) NO IDLE UP (AND ITS DIODE PACK OK) idle is only about 950 rpm. hot.

vacuum leaks are full power never lean, the MAP assures that.

dash post closed, and gap at end (of its plunger engine running

a bad IAC, in the base of TB or wrong gasket on TB and the  5 holes here must be blocked with gasket, or will fail.

https://fixkick.com/IDLE-AIR/Slide_Show/...ottom1.jpg

IAC must be tested to be closed at 150degrees, at this point closes an for sure 180f, hot engine,\
this is page 37 in my TB slide show. shows all ways to leak. (so many there are) even EGR valve cracked or gasket misssing.


as you can see blocking the air horn like you did kills dead  IAC and ISC both and bleed on 91+ to 98 usa.

lots of tests there are,  TV is TSP parked above. throttle valve butterfly valve.
like:
intake man is for A/T  tranny, is yours? A/t Modulator (3sp) hose or fitting on manifold bad. cracked. end to end if 3SP can leak.

you have a leak below the TV  after your air horn test.

anything in the blue arrow path below TV and all gaskets too below TV.

I guess the last one possible is cracked manifold.
Yes you can test the ISC for bad, by making  its gasket solid, not with air holes make it dead closed. (and help solve riddles like this)

more photos, this one page 39
you have all but the X  marked parts.


more
the TB 3 screw ISC gasket must not leak.
then all these.