i assume hot engine fast idle an with surge., help.
well it only surges for 2 reasons. (and one can cause other , for 2 times surging.)
1: all lean engines surge. and if the iSC works it will try to correct the illegal RPM and make it go away or make it worse, (the leaner the worse)
2: ISC is out of control, either for above reason or there are air leaks.
3: lets say engine is rich for some reason (error 1 lets call it) and then error2 an illegal vacuum leak, the engine will scream. excess Fuel + air = scream.
no scan tool to connect this ECU?, all scan tools work here, and makes diagnosis 10x more easy.
Is the engine getting hot? 180F or more and holding. if not it will scream due to IAC open all the time.
ok, it's hot, does the IAC closes above 150F. it must or the engine wills scream .
if you pinch the ISC air line (2 are hot water (Felt) and 1 is air, pinch the cold one, 800 rpm hot engine, it drops to 400 and stalls.
if racing , say at 1200 rpm, pin and it hits,800. (1200-400)
is the throttle cable slack, it must never be tight.
the TV is closed 100%
so the only normal air , is ISC + bleed hot. so close the bleed. what is the RPM NOW hot. (turn CW, direction, do not force it in to seat. gently)
here is my new fast page. might work.
these checks put us on track. to true cause.
http://www.fixkick.com/IDLE-AIR/fastfix.html
we can find it. its not too hard with some simple checks.
as long as manifolds are not cracked, or injector cushions leaking or 2 problems.
first lets get hot closed loop working, this is necessary, then set idle.
when moving(swap) engines, and for sure MPI ,this engine uses a MAF sensor,
the MAF sat at the air cleaner box. and the long pipe from there to the induction(intake TB, and plenum) must not have any air leaks at all.
This is how mpi WORKS. It must measure all air sucked into the engine or all bets are off.
if you get leaks it goes lean. (all else working and 02 can not correcting , this massive air leak.)
if not in closed loop, at idle that means the 02 is not correcting for things like air leaks.(vacuum leaks) or is out of control. (both)
if the engine goes lean the rpm drops, then the ISC will open and if it cant get rpm up from lean, say 600, it then hunts. << not your case.
if how ever. there are 2 problems (and closed loop dead) if say the FPR is bad. and fuel pressure too high, it (AFR) goes rich, and any air leaks (problem 2) causes racing.
and the ISC then closes to correct rpm down to 800 (say from 1200), and if it cant,. it hunts. (really THE ISC is just a servo and hunting is its bag) It just tries hard.
under normal conditions the iSC is only correcting timing changes and does it so fast you dont notice it.
ISC is electric. (electric air valve is all it is)
IAC is thermal, it is closed 100% hot, so is not a factor if working.
iac is open cold and idle races 1200 to 1500 rpm and the ecu does not try to set idle to 800 under cold conditions , using the ISC,
when the engine hits over 150 , the ISC wakes up. and runs the show., that is runs idle at 800 or goes nuts.
it's hard coded, 750 to 850 RPM is a hard coded software rule. and the iSC works hard to do that. (isc is software + hardware)
so 180F is important as is the water tube at the IAC, gets hot say near 170 by heat gun measured. for sure way over 150f pointing there. or the line is clogged, missing or bypassed during the swap? or connected wrong.
in an early post you said fast idle ended with IAC port blocked, well that is only caused by 2 things.
it's bad,.
or is not hot.
easy peasy
its only like 5 wires to get scan tool working. if the orig harness is missing this part.
12v(p16)
ground (p4/5)
2 comm lines.
i need both rpm's low and high, hot.
and what parts are missing. (engine, sensors. harness, induction parts, sensors.etc)
well it only surges for 2 reasons. (and one can cause other , for 2 times surging.)
1: all lean engines surge. and if the iSC works it will try to correct the illegal RPM and make it go away or make it worse, (the leaner the worse)
2: ISC is out of control, either for above reason or there are air leaks.
3: lets say engine is rich for some reason (error 1 lets call it) and then error2 an illegal vacuum leak, the engine will scream. excess Fuel + air = scream.
no scan tool to connect this ECU?, all scan tools work here, and makes diagnosis 10x more easy.
Is the engine getting hot? 180F or more and holding. if not it will scream due to IAC open all the time.
ok, it's hot, does the IAC closes above 150F. it must or the engine wills scream .
if you pinch the ISC air line (2 are hot water (Felt) and 1 is air, pinch the cold one, 800 rpm hot engine, it drops to 400 and stalls.
if racing , say at 1200 rpm, pin and it hits,800. (1200-400)
is the throttle cable slack, it must never be tight.
the TV is closed 100%
so the only normal air , is ISC + bleed hot. so close the bleed. what is the RPM NOW hot. (turn CW, direction, do not force it in to seat. gently)
here is my new fast page. might work.
these checks put us on track. to true cause.
http://www.fixkick.com/IDLE-AIR/fastfix.html
we can find it. its not too hard with some simple checks.
as long as manifolds are not cracked, or injector cushions leaking or 2 problems.
first lets get hot closed loop working, this is necessary, then set idle.
when moving(swap) engines, and for sure MPI ,this engine uses a MAF sensor,
the MAF sat at the air cleaner box. and the long pipe from there to the induction(intake TB, and plenum) must not have any air leaks at all.
This is how mpi WORKS. It must measure all air sucked into the engine or all bets are off.
if you get leaks it goes lean. (all else working and 02 can not correcting , this massive air leak.)
if not in closed loop, at idle that means the 02 is not correcting for things like air leaks.(vacuum leaks) or is out of control. (both)
if the engine goes lean the rpm drops, then the ISC will open and if it cant get rpm up from lean, say 600, it then hunts. << not your case.
if how ever. there are 2 problems (and closed loop dead) if say the FPR is bad. and fuel pressure too high, it (AFR) goes rich, and any air leaks (problem 2) causes racing.
and the ISC then closes to correct rpm down to 800 (say from 1200), and if it cant,. it hunts. (really THE ISC is just a servo and hunting is its bag) It just tries hard.
under normal conditions the iSC is only correcting timing changes and does it so fast you dont notice it.
ISC is electric. (electric air valve is all it is)
IAC is thermal, it is closed 100% hot, so is not a factor if working.
iac is open cold and idle races 1200 to 1500 rpm and the ecu does not try to set idle to 800 under cold conditions , using the ISC,
when the engine hits over 150 , the ISC wakes up. and runs the show., that is runs idle at 800 or goes nuts.
it's hard coded, 750 to 850 RPM is a hard coded software rule. and the iSC works hard to do that. (isc is software + hardware)
so 180F is important as is the water tube at the IAC, gets hot say near 170 by heat gun measured. for sure way over 150f pointing there. or the line is clogged, missing or bypassed during the swap? or connected wrong.
in an early post you said fast idle ended with IAC port blocked, well that is only caused by 2 things.
it's bad,.
or is not hot.
easy peasy
its only like 5 wires to get scan tool working. if the orig harness is missing this part.
12v(p16)
ground (p4/5)
2 comm lines.
i need both rpm's low and high, hot.
and what parts are missing. (engine, sensors. harness, induction parts, sensors.etc)
http://www.fixkick.com