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Alternative IACs?

  • Thread starter Thread starter Ethereal_Zer0
  • Start date Start date May 23, 2025
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Ethereal_Zer0

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#1
  • May 23, 2025
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I did a search but couldn't find anything so I am hoping you guys can help me out. I have a bit of a strange question regarding IACs and which ones can be used on a 1990 5.0L. I have a modified 306 with a Terminator X system. Usually it runs well but I have had intermittent IAC issues since I bought the car, but was able to smooth it out by tuning the car. Recently I started having issues again (just a slightly high idle and occasional RPM bounce). I have tried switching out for another stock one and didn't see any difference.

The guy who I purchased the car from said it has an IAC from a Ford Focus installed, but couldn't remember which year it had come off of. I have looked online and seen IACs for both the Ford Ranger and Ford Bronco that look similar as far as mounting and where the inlets are located, but I am curious what the actual difference if any (other than the layout/form) is between each of these units? Does the IAC from a Focus, a Ranger, or Bronco flow any better than a stock unit?

I have everything to simply swap the IAC to a 4-pin GM style which I have been told runs better than the Ford units due to having a stronger IAC motor, but it would be nice to stick with the 2-pin since that is literally plug and play. I am also considering getting one of the IAC adjusters from LMR also to see if that helps at all. Does anyone have any experience with mix and matching IAC valves or using one of these adjusters? Are there any 2-pin IAC motors that would fit but breath a bit better?
 

Noobz347

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I have heard of folks going to GM style IAC for aftermarket fuel injection ECUs but I don't think I've seen anybody try to adapt one to a Ford ECU.
 
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Ethereal_Zer0

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Noobz347 said:
I have heard of folks going to GM style IAC for aftermarket fuel injection ECUs but I don't think I've seen anybody try to adapt one to a Ford ECU.
Click to expand...
It's got a Terminator X system so I can run the wires back to there and add it as inputs if necessary. Just trying to avoid running more wire if possible.
 
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Noobz347

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Ethereal_Zer0 said:
It's got a Terminator X system so I can run the wires back to there and add it as inputs if necessary. Just trying to avoid running more wire if possible.
Click to expand...

Don't the Temi-X guys have specific IACs that they recommend with their systems?
 
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Ethereal_Zer0

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That's something else I was wondering. I tried searching for one on Holley's site, but didn't find anything there either. I may have just been looking in the wrong spot, but I searched their store and nothing came up.
 

Noobz347

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https://grok.com/share/bGVnYWN5_574abee6-6947-47fc-a701-9ed333e05a63
 

Kid wita 5oh

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08 ish Ford fiesta....bolts to fox tb and has a gm style stepper motor.... Plugs right in to the existing iac plug on the term x harness(unless you have a foxbody specific harness with the ford plug).. But then just run the overlay and a new pig tail
 
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Ethereal_Zer0

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Ooooh good call guys! I didn't even think about asking AI this question! Finally AI comes in handy beside weird videos of Will Smith eating spaghetti lol. Thanks @Kid wita 5oh I think that's exactly what I am looking for. I'll give this Fiesta IAC a shot next week and report back!
 

Noobz347

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Ethereal_Zer0 said:
Ooooh good call guys! I didn't even think about asking AI this question! Finally AI comes in handy beside weird videos of Will Smith eating spaghetti lol. Thanks @Kid wita 5oh I think that's exactly what I am looking for. I'll give this Fiesta IAC a shot next week and report back!
Click to expand...

Yeah, the AIs are [not] really good at creating stuff but they are awesome "search monkeys".
 
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Ethereal_Zer0

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So I ended up giving up on this quest. Motorcraft IACs are nigh impossible to find it seems. I ended up pulling my IAC off and hosed the out of it with brake cleaner. I'm almost more confused now that I had it off and looked at the part number that is on it. It isn't anything I recognized but it appears that the previous owner pulled the motor and the valve apart, switched out the valve and body with a different part (potentially from a Focus or Fiesta, gonna keep looking to try and figure it out exactly) but re-attached the original fox body IAC motor. So far so good with it just being cleaned though, hopefully that will fix me. If not, I'm just going to swap to the 4-pin and run the new wiring back to the Terminator X ECU.
 

CAMTWO1070

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Dec 17, 2021
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Jun 7, 2025
#11
  • Jun 7, 2025
  • #11
Ethereal_Zer0 said:
I did a search but couldn't find anything so I am hoping you guys can help me out. I have a bit of a strange question regarding IACs and which ones can be used on a 1990 5.0L. I have a modified 306 with a Terminator X system. Usually it runs well but I have had intermittent IAC issues since I bought the car, but was able to smooth it out by tuning the car. Recently I started having issues again (just a slightly high idle and occasional RPM bounce). I have tried switching out for another stock one and didn't see any difference.

The guy who I purchased the car from said it has an IAC from a Ford Focus installed, but couldn't remember which year it had come off of. I have looked online and seen IACs for both the Ford Ranger and Ford Bronco that look similar as far as mounting and where the inlets are located, but I am curious what the actual difference if any (other than the layout/form) is between each of these units? Does the IAC from a Focus, a Ranger, or Bronco flow any better than a stock unit?

I have everything to simply swap the IAC to a 4-pin GM style which I have been told runs better than the Ford units due to having a stronger IAC motor, but it would be nice to stick with the 2-pin since that is literally plug and play. I am also considering getting one of the IAC adjusters from LMR also to see if that helps at all. Does anyone have any experience with mix and matching IAC valves or using one of these adjusters? Are there any 2-pin IAC motors that would fit but breath a bit better?
Click to expand...
You need this IAC adapter to use a 4 wire GM style IAC....Its sold by ACCUFAB..............



Good Luck
 
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