High idle, probably broken IAC, questions

[fixkick]

Car works fine enough without it as I don't have AT creating extra drag trough torque converter so its very minor nuisance. what?
your  first post shows 1991 Vitara MT, 2 door, G16a, 4wd.

MT is not AT./ no mt has any kind of torque  converter,  I am so confused now.  and you are correct A/T box shifted Park to drive and NO ISC working will love to stall.


With luck I might find analog voltmeter from there.. everybody has stored all kinds of shit from 1920's to nowadays so might even find one.
the cheapest meter sold on earth is that, seen on all stores, even walmart here.  for $9 USD.


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.

Thanks again for that info package. I think I now understand how to correct the ISC issue.

Mine did hunt before when semi warm until I hacked the IAC. It did not affect driving much. So yeah that confirms with A/T the hunting is really bad, probably due to the very aggressive ISC profile. And I dont pull from full stop with MT without pressing throttle pedal, so that also eliminates the ISC.


Sorry for being bit confusing there. I mean to say that ISC not working is very minor minor problem as I have manual box. Also meant to tell that I know it would be huge problem with A/T as the engine would stall when switching to Drive.


My country has only 5.5M population and spread across quite a lot of land. So we have limited selection of tools and stuff on shops. For example I have not seen analog voltmeter in 20+ years. Have to look up internet, someone on EU area must be selling those.


I took a pick of my TB, sorry could not get to better angle with my camera. I marked one spot with red arrow that looks like it could have a screw, but there is only short cavity without screw.





I know sports car tuners and race car guys have all kinds of exotic systems. I was helping my friend as a bolt/wrench boy role when he built his Mk4 Supra.

From stock 330hp twin turbo to 1000+ hp single turbo ethanol monster... new ecu, new injectors, whole engine rebuild with stronger parts, 3 plate clutch, hardening gearbox, brakes, springs, shocks... so basically chassis and seats stayed as they were.. Self made ecu map and the works. Can just say that wow it was expensive and wow you really need the seat's backrest with that one. And maybe some driving skills.

just be sure the TPS idle switch is closed at hot idle and driving will be so  much better. (ok, still M/T) great.


one other way (food for though)
using and old VSV valve,  vacuum solenoid valve, like what is used for the dash pot?

use these with 12v( ign, on) power wire to and added   VSV (vac, solenoid valve) and a toggle switch.
then with the VSV  and a tuned 1 orifice  ,  . you have binary controlled bleed valve.  for cold operation.
or 3 way VSV for hot/cold and 2 orifices..
then tune the orifices one for hot and one for cold.  

set (tuned  before) one way for cold and 1500 rpm
as engine warms the 1500 goes way to high(too much air) "screams RPM at bout 150f water temp"
then throw the toggle switch and 800  ISC regulated RPM happens.

then latter you could add  thermal switch  device to water hose (a sensor) that closes (using a relay) to the above. toggle switch now removed.
using sensor you choose as best,  150F or what ever you want ovoid the screaming RPM that you wish to avoid.

note how this way is progressive from very simple to more complex but still easy to over time. (improvements)

3way  (output to way 1 and way2 path)
https://www.summitracing.com/parts/rnb-911-404


2way (open/ closed) (fo cold engine only)

https://www.summitracing.com/parts/rnb-911-601



cheers had happy summer !