A couple very noob questions

[Blue88Comanche]

as the title states i have a couple of noobish questions.

 

First: How does the IAC work?  More precisely how can it be overridden?  Is it controlled via varying voltage or ohms?

 

Second: is the sensor on the 97+ 4.0 thermostat housings a temperature sender, switch, or both?  

 

thanks,

[Eagle]

I would need to do some research to try to answer the first question.

 

As to the second question, it's a sensor, not a switch. The sensor feeds input to the PCM, and the PCM then controls whatever needs controlling.

[Blue88Comanche]

I would need to do some research to try to answer the first question.

 

As to the second question, it's a sensor, not a switch. The sensor feeds input to the PCM, and the PCM then controls whatever needs controlling.

 

So because it is a sensor, can it be hooked up to an aftermarket gauge or would i need an aftermarket sensor as well?  currently for temperature i am using the factory renix sensors.  I have a 97+ thermostat housing with a sensor acting as a plug.  I was wanting to use it now as aux temperature sensor, or if available find a temperature switch that will work with the housing for the aux fan.

[Blue88Comanche]

bump

[yxmj]

Well you are asking 2 questions?

 

But I will try......You would be best to use the sensor that comes with the aftermarket gauge. The Factory one would be calibrated to be used by your PCM....I would think it would be a long shot that it would send the required signal to an aftermarket gauge.

 

Look Up the Thread By Hornbrod.....I followed His advice and it works perfectly.......it is better to mount the sensor for the fan (if you have to choose a spot to mount it) in the lower return line of the rad.....you would get your best heat info there.

[Zebvance]

Why would you want to override the IAC...... I don't under stand.

[Blue88Comanche]

Suppose you wanted "extended idle" or "Up Idle" or "High Idle" or whatever you would like to call it. there has been a basic workaround for renix units (located here).  But I thought of a potentially better alternative or several ideas at least.  I'm just not sure how the ECU controls the IAC.  Does it control it by varying the voltage or resistance (ohms) and that is the operating range (from max open to max closed)?  

 

I'm thinking about possibly making a separate circuit that is toggle-able via a relay. (off = stock circuit, on = custom circuit)

[Zebvance]

Suppose you wanted "extended idle" or "Up Idle" or "High Idle" or whatever you would like to call it. there has been a basic workaround for renix units (located here).  But I thought of a potentially better alternative or several ideas at least.  I'm just not sure how the ECU controls the IAC.  Does it control it by varying the voltage or resistance (ohms) and that is the operating range (from max open to max closed)?  

 

I'm thinking about possibly making a separate circuit that is toggle-able via a relay. (off = stock circuit, on = custom circuit)

 

Oh I got ya. We theoretically you should be able to wire a on off switch with a bypass of course followed by a potentiometer. That should work.....

[Stacks]

Why get so complicated?  Use a bike shifter or brake cable actuator or use a relay controlled solenoid and just open the throttle with it to the rpm you want. I used the solenoid set up on my TJ for using the on board welder and the bike cable set up to bump the idle up when using the on board air on the MJ. Simple s good.

[Blue88Comanche]

Why get so complicated?  Use a bike shifter or brake cable actuator or use a relay controlled solenoid and just open the throttle with it to the rpm you want. I used the solenoid set up on my TJ for using the on board welder and the bike cable set up to bump the idle up when using the on board air on the MJ. Simple s good.

... well i tend to over think things and over look the simple options...

[Stacks]

Welcome to the club!  :laughin: