jerking

[fixkick]

dang that's ugly (1000 words one photo....)
but id not tempt fate, any engine that runs with empty gas tank, is a dream boat. engine. LOL
i see it s show hot. (shows normal on the gage)
WHY is it racing, the variance, i just chock up to the ISC (servo trying to drop idle to 800 and fails, resets, fails, resets. repeats)
id ignore that part.
so fix the crazy bad idle.
my first guess, is a huge vacuum leak.
Cause: and full symptoms.
that engines, hot. 180F, i presume, my hand instinctively touches top rad hose, ahh its at full temp. or IR gun shows ah,, 175f on stat housing and IAC base, all the IAC is hot took , now that is real good, so it can close, and not stay open i think to sell.
we can see if engine is in closed, loop now, so cant know if AFR, perfect, or way lean and Long term fuel trim is way off showing gross lean.
that is the #1 test for me on all EFI cars. what is AFR doeing. Fuel mix.....????? lean, normal, rich????
we dont know we are blind.
So blind id work that insane high idle.
First off this car runs with MAF sensor that measure air. flow into the engine. The ECU adds fuel bases mostly off this MAF. sensor.
That means there are 2 air leaks. unmetered air and metered.
ummetered air causes lean , metered not, but metered races. (unmetered air , causes slow rpm due to lean, if not in Failsafe mode)
Lets pick illegal metered air.
1: the TV stuck open or throttle cable stuck tight, both cause same effect the butterfly valve is not closing 100%
2: ISC stuck open , or the water line to it , or in it , fully packed in rust /scale, causes no flow , no heat. to it. it closes about 150F.
3: the TB air bleed was unscrewed, or is missing. See top black cap on TB body ? that is the air bleed, idle duty cycle setting device.



26 ways to mess up idle
http://www.fixkick.com/IDLE-AIR/16v-idle.html

what i do is close each metered air device 1 by one. a, b, c,d
to find the leak.
there are only 4 legal air sources, except d. d is closed at all time at idle. IS IT? LOOK at it.



(if the engine is running way rich, I dont know , no scan tool but if it is, all air leaks cause fast idle. ALL. (cracks, gaskets and seals)

for sure the illegal air is behind the TV , throttle valve. or in the TB.

see other posters photos here.
see this nasty mess?



this mess can block any throttle open (EGR clould hits PCV cloud and gunk happens)








see lots of photos here,
http://www.fixkick.com/IDLE-AIR/16v-idle.html


see this? see the rectangular port with red arrow pointing at it. you can block that with clay and prove, IAC good or bad, hot.