1989 screamer

[Flamecat68]

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 vaccum 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. 

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.

[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.

[fixkick]

tricks of the trade more,
an illegal TB base gasket. made by you.
seen here,
steps

TV 109% closed (99.99% or set it just under 0.001" inche gap, I have feeler with 0.0005" and use that. until later all runs perfectly too slow.
1: tb pulled if 3speed car, it has 2 gaskets, one is below the intake heater and one on top.
make a gasket and for sure 5 holes blocked per normal.
2: but now block IAC hole



I made a good one by hand here, so make one like it but IAC hole blocked. doing so makes engine starts impossible with 0 air.  so use 5% right foot throttle to start engine.
as you can see with TV closed there is ONLY 1 path for air, and tha tis IAC bleed air port , below and the vacuum port ARC seen below, you can block both, do that then cut the arc, , see what happens on both. there and not there.


SMP maker kit.

[fixkick]

on good engine, all.
hot. 180f hot. no bad thermostats or missing allowed.
the IAC is closed, hot.
and blocking this #8 gasket will stall engine. or run at 200rpm and shake hard with only TV gap air supply.





here is disection of ISC I forgot we had,  make a sold gasket to replace correct one with no holes. air holes.

https://fixkick.com/IDLE-AIR/1989-90/ISC...index.html

[Flamecat68]

Thanks for the support i will continue to keep the air horn blocked and start sealing it off. Ill use the ol hit and twist impact driver on them lovely phillips heads and plate off the isc air loop to eliminate a air path and see if it still wants to run choked out. 

IAC has clay in it electrician duct seal totally making that loop moot already. 

3 speed auto. Has the 2nd nipple for the th180 suck shift awesomeness. The rubber line is crap fits like shit will replace for a solid seal. And i have not confirmed the line down to modulator  so ill make sure i can pull vac pressure after replacing prior to connecting to intake to confirm. 

Will block egr for testing purposes after that.

Ill tear down the throttle body if it wants to run and address all leak points. Can i use a thin coat of permatex motoseal a gasoline suitable to dress the gaskets to ensure a mint seal? I know overdoing it will squeeze out and disassembly will be a little more tacky down line but i have seen so many tb gaskets with a blown out paper chunk a bit of glue should not hurt anything? 

Cracked intake/shot gasket at block could be confirmed by fully deleting all airpaths booster. Iac, isc, trans mod, egr port but leave the MAP for ecu to reference if the leak there? Prior to removal.

Removal of intake filling of water or build a block plate and pressurizing to 5 psi and see if it stands like a head pressure to truly confirm crack? 

Just to confirm 1989 and 1990 have no aldl or SDL capability? I threw down on rhino power to help with the 91 to 95s just awaiting for the interfaces to arrive should be anyday now. 

I have a seperate truck 5 speed with a 20 to 16 hg vac. 4 hg vac flutter idle with 160 psi comp all 4 cold WOT dome fuse removed. Awaiting a leak down kit to check for valves another vac style issue before pulling hair out or setting fire to it. Going to throw a hail mary and check valve clearences while waiting.

Would love to be able to backprobe the circuitry through a simple port vs metering all sensors using that port .

Will make a new thread if i hit a wall and i do have a diesel AAZ vw with acme kit to solve it worst case. Ecu ignition delete kit haha. Would be rad if theres a way to talk to a gold box. 

Thanks for your support got some work to do to get the hard data on whats up or down.

Cheers

[Flamecat68]

Also the plenum heater black plate two wires can i delete that? To prevent the extra gaskets required and simplify the design? My 89 5 speeds seem to not need it and i warm my truck up 5 minutes prior to running no smog requirements so i dont see the harm i know its for atomization etc but the fuel savings vs a vac leak ill pay to play haha. Thanks boss

[fixkick]

Also the plenum heater black plate two wires can i delete that? To prevent the extra gaskets required and simplify the design? My 89 5 speeds seem to not need it and i warm my truck up 5 minutes prior to running no smog requirements so i dont see the harm i know its for atomization etc but the fuel savings vs a vac leak ill pay to play haha. Thanks boss

ok this is  a 5speed stick box. (told now)
not 3speed
so make real sure the  3speed intake manifold has no VACUUM MODULATOR port , there and if is there is not leaking air. it for sure is not used this port on any 5speed. nor 4speed A/T
the heater is only for the 3speed,
so is useless.
yes get rid of that and only use the 5speed gaskets.

you have this huge leak some where, intake plenum induction leak is the brake booster tested for no leaks?  (I use cork on the hose leanding to it) to prove that. so easy

btw the fast idle pins are A13 not at zero volts, ground is fast idle for steering overloaded (PS)
A2 pin is fast idle to from DIODE "OR" logic gate device,  A/C on,  headlamps on, Blower on, or rear defrost heater option on.   must be

page 9 here shows idle up pin A2 and A3... A2 is A/C active, and A3 idle up all others.
a2 =12vdc = idle up command
A3= 12vdc = idle up.  
https://fixkick.com/ECU/89/1990-scan-ECU/allpages.pdf

I will assume all things related on this  32 year old car,  all idle up's bad,  and air leaks, and TPS idle switch failing making ISC dead. and ISC and IAC leaking air.
i check them all, and be sure they are not wrong,  the air leaks all added up; add up more RPM.!
but once all air leaks are gone the engine stalls and needs right foot pressed a bit to start car, hot. cold the IAC adds lots of air below 150F


pin a14, must be zero volts at idle,  or the TPS is bad or never calibrated,  (5v here means ISC is offline, means unregulated RPM but not screaming)
below is crude lacking most pins.


vacuum leaks are not easy
as the master said, Archimedes, (before space craft) nature (on earth) abhors a vacuum. ( nature and time and aging love to  find a way to fill the vacuum with 14.7PSI sea level air.)

that in turn means  the gaskets crack and air sucks in like mad. (entropy) yours had 32 years to fail. not small that.

[fixkick]

how do you like my horse up (cribbed) PDF? above... 89/90 full car schematics.

[jwunsch]

@FlameCat68

If after finding your current leak(s) you find the IAC also leaking and not repairable as I did (only 28+ year old parts available, so soon same problem).

You can create manual cold start PRM boost with rogue vacuum hose and a moped's gas valve. A needle valve would be better, but I could not find one at the time and used moped gas valve.

This idea I got from fixkick. Just pointing it out in case you run in same problem after sorting out all of the other problems,

Pictures in last post of

https://fixkick.com/forum/thread-high-id...ons?page=2

I have moved the hose on driver's side and replaced golf-tee with the moped's gas valve.

ps. @ Fixkick At least I like those schematics. Thanks for those.

[Flamecat68]

What a journey. IAC was defeated using clay duct seal but it would move out of the way suck a bit into the TB and fail to stand up to the vacuum. Two attempts of this fail.

Jerry it is a 3 speed sorry for the confusion the vac modulator had a open circuit on the trans side aka screamer.

Did your line the bore with tape prior to clay seemingly sealed. Hopefully stays blocked forever haha

ISC i made a paper gasket from oil filter top just two holes and some rtv and inserted it to block the 3 holes.

300 rpm on the tach runs smooth. Winning

Unblocked ISC warmed up 150f ecu held 800 to 900.

Somewhat in control now. I have the egr vac line disconnected and my vac gauge on it reading 20hg steady
Evap line is disconnected from the manifold as well.

Cold start Dash pot i have hardlined onto the manifold bypassing the VSV valve for a non ecu controlled start

Just restarted it semi cold 1200 rpm in park
800 to 900 in drive steady vacuum.

Its seemingly happy with this configuration but i want to hook up the egr for the inert gas. My only thing is the top of the vacuum switcher on top of the bark tube. Does that not pull fresh air through the sponge down the P back to vsv and mani?

Cracked the outer thread of the iac housing using a hammer to hit and and twist the Philips out. Epoxy the crack got lucky. You can turn that funny plate with a 17mm if the threads good using a 17mm on the 6 round knubs. Will make a tool drilled washer welded on a 3/8 extension to be able thread up leaky ones onto the IAC needle.

By moped fuel valve to do you mean a fuel tap or petcock on off to control the vacuum on the cold start dash pot? It appears you T'ed in on the vsv supply from manifold to cause the dash pot to bump 500rpm until the ISC takes over?

Misery loves company will keep putting it together and test the headlights rpm idle up etc. Wicked diagrams and labeled air paths love your notations added to make things extremely friendly to read condensed.

Tomorrows a big push to road test on the street underload will keep posted.