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High idle, probably broken IAC, questions
#24
E17 market is Sweden ,sorry I forgot that. best is have signature in posts.
1991 Vitara MT, 2 door, G16a, 4wd. (market E17 Sweden, regardless of location this car is E17 no guessing)

with the wrong meter, digital
and diode and a cap. say 1UF 20Vdc.

the diode converts AC to DC called rectification.
the cap charges to peak. input voltage.
unless it is huge uF and has a resistor added.(IDK), and then the voltage is less. to do laws called RTC time constants. T=RxC. (R = 0 = wire)
so there is no answer. lacking cap value. but...
a small cap used will charge to 14vc fast (alternator voltage) charging voltage. 13.3. volts is battery float voltage, not charging nor discharging (lead acid car battery)

this is all useless, as we want to know actual duty, 50% high then 50% low on the square wave that is 2.5mS high , 2.5mS low. Period is 5mS. 0.005 seconds.
it is so hard to do that suzuki sold there own meter to do that just for this car, the FSM factory manual even names it.

the ISC has a 2amp driver , (6ohm coil ISC) this is very powerful signal
and in to any meter , the meter is not going to load down that 2 pin wire set
adding a diode to that pin is not any kind of resistance (T = RxC) R = 0.
that means the cap (added to end of diode) adds no resistance and charges to peak.
the DIODE then reverse bias (off) and the cap can not discharge to the low state driver or to the coil ISC, so sits at 14vdc all day long.


do your really have Automatic trans-missing?????? or the MT 5 speed.

the ECU for A/T box is unique.
that A/T ECU actually sees you shift out of park and (park pin goes to false logic) the ECU changes to a very aggressive new idle controls to heat up (joking 1/2) the torque converter clutch.
The magic ISC then holds 800rpm hot doing that,using totaly more aggressive ISC tables of modulation.
if the iSC is dead the engine stalls or on very good engines runs a 200 rpm and does not.
when you move the throttle with the right foot 1mm the ISC goes off line, dead ISC by design or the driver will crash (ask Toyota how billion $$$ law suit is to lose on that)

My 91 has the ISC hunt error, a true man killer , in A/T (teens etc not wise) it hunts like mad if he DP fails. and no lawsuits yet.
in drive it is a man killer (no me) for sure, in DRIVE, as car lurches madly ahead
so do you have A/T tranny??????
http://www.fixkick.com
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RE: High idle, probably broken IAC, questions - by fixkick - 07-08-2021, 03:42 AM

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