"When motor is warm - pinching the hose or removing the connector doesnt change idle!"
this is wrong, this fact proves the ISC is closed, the if not stuck closed) the ecu has it closed. and means there is no idle speed regulation. (downward)
The tps idle switch must be closed it idle, 50 to about 300ohm (over 500 is trip point and failure,) failure means, idle controls are suspended buy ECU.
the ISC calibration, is best down with a scope on the ISC pins, for 50% duty cycle, adjust the air bleed for 50% on iSC inputs signals. (or use a dutycycle meter on same pins.
i think its a 200 Hz signal. so 50% is symmetrical square wave.
if the bleed is set wrong, say out too much the ISC closes more , and if too much out, the isc closes to 100%, meaning more bleed air , will cause idle to rise above 800rpm hot
as you close the bleed, the ISC starts to open more,and if bleed is 100% closed the ISC opens to max.
THe TPS is the first thing the must be right.
if all other parts are good then only the dutycycle needs to be set if off.
the book shows using a custom tool to set DC, that has its own current source so we dont have that and a scope or DC meter (built in to some DMM's) work best.
sounds complex but is not, all your parts seem to be good. id get the Tps closed.
if the TPS is good. then the bleed is set wrong. only.
high voltage is ISC open, and faster idle, and low voltage ,closed and slow idle. i have the bleed open a tad too much...
scope has ground buster on it.
![[Image: iac-wave1w.jpg]](http://www.fixkick.com/IDLE-AIR/iac-wave1w.jpg)
once correct and in the middle the ECU can control about 400 too much or 400 too little RPM (+-400) so when you put all electric loads on engine it can open wider, then when engine rpm wants to be too high ,say on a day you are have cold dense air and low altitude(more HP), the ISC then closes down.
this is wrong, this fact proves the ISC is closed, the if not stuck closed) the ecu has it closed. and means there is no idle speed regulation. (downward)
The tps idle switch must be closed it idle, 50 to about 300ohm (over 500 is trip point and failure,) failure means, idle controls are suspended buy ECU.
the ISC calibration, is best down with a scope on the ISC pins, for 50% duty cycle, adjust the air bleed for 50% on iSC inputs signals. (or use a dutycycle meter on same pins.
i think its a 200 Hz signal. so 50% is symmetrical square wave.
if the bleed is set wrong, say out too much the ISC closes more , and if too much out, the isc closes to 100%, meaning more bleed air , will cause idle to rise above 800rpm hot
as you close the bleed, the ISC starts to open more,and if bleed is 100% closed the ISC opens to max.
THe TPS is the first thing the must be right.
if all other parts are good then only the dutycycle needs to be set if off.
the book shows using a custom tool to set DC, that has its own current source so we dont have that and a scope or DC meter (built in to some DMM's) work best.
sounds complex but is not, all your parts seem to be good. id get the Tps closed.
if the TPS is good. then the bleed is set wrong. only.
high voltage is ISC open, and faster idle, and low voltage ,closed and slow idle. i have the bleed open a tad too much...
scope has ground buster on it.
once correct and in the middle the ECU can control about 400 too much or 400 too little RPM (+-400) so when you put all electric loads on engine it can open wider, then when engine rpm wants to be too high ,say on a day you are have cold dense air and low altitude(more HP), the ISC then closes down.
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