Where is my IAC? Rough Idle [2.8]

[natertot]

I thought carbed engines weren't supposed to have an IAC but I guess this one does? Weird 80s stuff. My idle is rough, I have a code for running lean, and I'm getting code 13 KOER, but KOEO is all clear. I suspect IAC.

Rockauto claims that this pic is the IAC, but I thought this was the throttle position sensor? Does anyone have intel?

"Idle speed control motor or air bypass not controlling idle properly" according to this site. Is this a reference to the thermactor air bypass valve?

 

[alwaysFlOoReD]

There are some people much more knowledgeable than me, but I'll take a stab. Some carbs had something that looked like your pic. And under the right conditions a rod came out and prevented the throttle from closing all the way. I don't know exactly how it worked, sorry.

 

[natertot]

There are some people much more knowledgeable than me, but I'll take a stab. Some carbs had something that looked like your pic. And under the right conditions a rod came out and prevented the throttle from closing all the way. I don't know exactly how it worked, sorry.

Thanks, the plunger on that hits the plate that controls the throttle. Not sure how to adjust it or if there’s a separate motor somewhere else, so hopefully someone else will have some advice there

 

[rusty ol ranger]

There are some people much more knowledgeable than me, but I'll take a stab. Some carbs had something that looked like your pic. And under the right conditions a rod came out and prevented the throttle from closing all the way. I don't know exactly how it worked, sorry.

Those were usually used to bump up idle during AC useage.

I dont know about the feedbacks like on your 2.8 but usually you adjust the mix screws then set the idle off the speed screw by the throttle lever.

 

[tw205]

IAC is not controlling your fuel mix (lean or rich). It simply controls idle speed.
The TPS is mounted on the carb, passenger side where the rod for throttle plates ends. It simply monitors the position of the throttle plates.
Your issue is either a dirty carb or a bad o2 sensor.

 

[19Walt93]

2.8's didn't have IAC's, the picture is a throttle stepper motor that would control the idle speed. A throttle solnoid ahd 2 positions- extended or retracted- and a stepper motor could have multiple positions. There is a solenoid on the carb that the processor uses to control the fuel mixture. They failed in big numbers when Rangers were introduced until Ford revised the part.

 

[natertot]

IAC is not controlling your fuel mix (lean or rich). It simply controls idle speed.
The TPS is mounted on the carb, passenger side where the rod for throttle plates ends. It simply monitors the position of the throttle plates.
Your issue is either a dirty carb or a bad o2 sensor.

You're right and since I've posted this, I learned that the photo is of the ISC (idle speed control). It has a plunger that holds the throttle from closing all the way so it can idle without dying. I did have to re align it to get the right rpm, and I also adjusted my fast idle which was way out of wack. Still no solution but I at least learned something and beat the carb into shape a little. The code says the ISC is still not controlling idle speed correctly though even though my curb idle is like 730 so I'm not sure.