i forgot one, dizzy timing set all wrong can wreck idle speed.
and is a this odd chicken and egg deal, the freeze jumper is dead of idle is way too high......on some ECU's.
the timing needs to be near spec, 5btdc or as hood shows.
on a good system. if you advance the dizzy , rpm rises. the ECU uses this magic to trim idle speed fast , then corrects it with the slow ISC, as it catches up, most ECU do this trick on all cars.
so if timing is in ball park.
and bleed screwed in CW. and idle screams (oops got leaks i do)
and i thin pinch the not hot ISC hose ,(air) the idle on a good car drops to like 400 rpm or stalls.
it does that because you kill every drop of air.. its all gone.
the beauty of the 16v, (many) of the TB above, there are only 3 paths for air, and one is 99.9% closed (the TV Throttle Valve butter fly )
the 0.1% is to prevent jam or bore wear.
one guy here, had a racing motor with no air...... (a Kodak moment...... shocking to see)
a very sick , mangled 8v throttle body, your TB cant do that trick thank gosh.
the IAC leaks below TB (missing in photo above)
the TV is not closing
Bleed screw, (now closed)
The EGR port top of TB, will not do this. (it's very tiny)
The ISC on the front of plenum is stuck open. (pinch the hose see what it does)
16v is very easy to find, compared to any 8v or any speed density engine they are all lil horrors... on all cars. with them.
The MAF mass air density system is the best system, it adjusts for any thing. (its only fails with air leaks and goes lean and slower RPM)
there are always exceptions. in any complex system.
here is one , example'
say the system is rich full time, very rich, (failure 1) (pretend fuel pressure is say 66 psi, bad) (top symptom; is no CLosed loop at idle. fix that first)
then you get and air leak,, and it races. air + fuel = race, and it will.
its not supposed to, but does. (physics wins, ECU loses)
but you can starve all air to any 16v engine here easy and prove who works and who don't.
so if EFI is horrid rich
and the intake manifold leaks air it will race , and nothing can stop it. but our test proves that out.... easy.
my guiding light is Greg Banish
bless you man.
btw, my gut feel is your fine video sounds like EFI (ECU) caused surge.
if it was lean bog surge it be funny sounding. like it was chocking to death. (hot)
it sounds happy, and full of pep. to me. best i cant tell with cheap speakers...
it's ISC out of control and the ECU madly trying to gain it back...
this is a servo loop and they all can do that. given all ways to fail.
imagine farmers wind mill, water pump (i'ts not a mill but we call it that) it pumps water to the water cistern. for farm house or cows troth.
and the fan blades all point in to the wind and makes max power for the pump.
one day a drunk albatross hits the tail section and breaks off the tail and is now GONE.
the fan just hunts back and forth (surge) never to find the correct wind direction again.
this is servo, too. (100% mechanical and easy to see)
the ISC is the slave of the ECU, and has +-400 rpm authority (shooting from hip spec), if the ISC is not dirty.
if anything exceeds that authority, it will fail and may hunt. (others stick high or low, depending in failure mode)
I used to work on RADAR (huge) servos, they too hunted, sometimes.
Its also bad programming.... (some will say)
on a new Toyota (lawsuits) the new cars go to limphome (slug) at the first hint of idle issues.. rendering car near useless. 15mph car?
The beauty of this car the parts can be all adjusted, and each part can be bought , unlike new cars.$$$$$$$$
and is a this odd chicken and egg deal, the freeze jumper is dead of idle is way too high......on some ECU's.
the timing needs to be near spec, 5btdc or as hood shows.
on a good system. if you advance the dizzy , rpm rises. the ECU uses this magic to trim idle speed fast , then corrects it with the slow ISC, as it catches up, most ECU do this trick on all cars.
so if timing is in ball park.
and bleed screwed in CW. and idle screams (oops got leaks i do)
and i thin pinch the not hot ISC hose ,(air) the idle on a good car drops to like 400 rpm or stalls.
it does that because you kill every drop of air.. its all gone.
the beauty of the 16v, (many) of the TB above, there are only 3 paths for air, and one is 99.9% closed (the TV Throttle Valve butter fly )
the 0.1% is to prevent jam or bore wear.
one guy here, had a racing motor with no air...... (a Kodak moment...... shocking to see)
a very sick , mangled 8v throttle body, your TB cant do that trick thank gosh.
the IAC leaks below TB (missing in photo above)
the TV is not closing
Bleed screw, (now closed)
The EGR port top of TB, will not do this. (it's very tiny)
The ISC on the front of plenum is stuck open. (pinch the hose see what it does)
16v is very easy to find, compared to any 8v or any speed density engine they are all lil horrors... on all cars. with them.
The MAF mass air density system is the best system, it adjusts for any thing. (its only fails with air leaks and goes lean and slower RPM)
there are always exceptions. in any complex system.
here is one , example'
say the system is rich full time, very rich, (failure 1) (pretend fuel pressure is say 66 psi, bad) (top symptom; is no CLosed loop at idle. fix that first)
then you get and air leak,, and it races. air + fuel = race, and it will.
its not supposed to, but does. (physics wins, ECU loses)
but you can starve all air to any 16v engine here easy and prove who works and who don't.
so if EFI is horrid rich
and the intake manifold leaks air it will race , and nothing can stop it. but our test proves that out.... easy.
my guiding light is Greg Banish
bless you man.
btw, my gut feel is your fine video sounds like EFI (ECU) caused surge.
if it was lean bog surge it be funny sounding. like it was chocking to death. (hot)
it sounds happy, and full of pep. to me. best i cant tell with cheap speakers...
it's ISC out of control and the ECU madly trying to gain it back...
this is a servo loop and they all can do that. given all ways to fail.
imagine farmers wind mill, water pump (i'ts not a mill but we call it that) it pumps water to the water cistern. for farm house or cows troth.
and the fan blades all point in to the wind and makes max power for the pump.
one day a drunk albatross hits the tail section and breaks off the tail and is now GONE.
the fan just hunts back and forth (surge) never to find the correct wind direction again.
this is servo, too. (100% mechanical and easy to see)
the ISC is the slave of the ECU, and has +-400 rpm authority (shooting from hip spec), if the ISC is not dirty.
if anything exceeds that authority, it will fail and may hunt. (others stick high or low, depending in failure mode)
I used to work on RADAR (huge) servos, they too hunted, sometimes.
Its also bad programming.... (some will say)
on a new Toyota (lawsuits) the new cars go to limphome (slug) at the first hint of idle issues.. rendering car near useless. 15mph car?
The beauty of this car the parts can be all adjusted, and each part can be bought , unlike new cars.$$$$$$$$
http://www.fixkick.com