1G Is this IAC

[hoonigane]

Hello is it idle air control valve or what? 1g gs. Connector on top broke and im having idle problems and if so can you diassemble it? I tried screwing that white part on top where connector is, it is spinning but doesnt go anywhere. Or welding old connector on is the only option?

 

[pauleyman]

No. It's the idle stop switch. Buy a new one.
https://www.dsmtuners.com/threads/r...-merged-5-8-idle-position-switch-stop.332448/

If you have a 90 the isc is different than the pic in this thread.

 

[hoonigane]

@pauleyman thanks man and it can cause the car to die in neutral right?

 

[pauleyman]

@pauleyman thanks man and it can cause the car to die in neutral right?

There is no way for me to answer that. It will tell your computer whether or not the throttle is closed and yes that is part of the idle circuit. Is it your only problem? I don't know but you do need to fix it before making further doagnosis.

 

[steve]

I call them the Idle Position Switch (because the FSM does) but it also acts as the throttle stop screw.

As the stop screw it sets the lower limit on how far the throttle butterfly can close and therefor the base idle speed. It for this function that the FSM says not to touch it because the adjustment is critical to proper idle.

As the idle position switch it tells the EU that the throttle is closed so it can perform it's idle control and if the throttle position was open before allow the ECU to emulate a dash pot with the ISC/IAC.

A defective IPS can cause the car to die/stall when the throttle is closed.

FYI these are ISC/IAC's.
1990 version

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1991+

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1991+ Plastic revision

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[hoonigane]

@steve thank you, very helpful. I tried to solder broken IPS, but did a poor job, so now when I connect it, car does not rev over 2,5k rpm and on idle it jumps from 1-1,5k constantly, no matter if ISC is connected or not. I think its shorting. So I will get new IPS and report back.

 

[steve]

The reving up and down over and over is what's called idle surging. It's the ECU cutting fuel when the RPMs exceed what the coasting idle is programmed to and then turning the fuel back on when the RPM's hits the lower bound to avoid stalling. Without an IPS the ECU never knows the throttle is closed and doesn't run this code.

 

[hoonigane]

@steve thanks for being helpful and understanding and not just saying to google stuff changed IPS today. RPM's are stable but on neutral it sounds like engine is misfiring. There are no error codes. Thinking of changing spark plugs or fixing up generator bc its charging 16 volts right now.

 

[steve]

Thinking of changing spark plugs or fixing up generator bc its charging 16 volts right now.

Regulator in the alternator is shot and battery is soon to follow. Lost a Optima red top to the alternator cooking the water out of it. If I remember right I lost both headlights too.