Foxbody Terminator X IAC Valve Upgrade - Fiesta Style
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- Опубліковано 4 чер 2022
- In this video I show you step-by-step how I upgraded my foxbody using the Holley Terminator X computer, to use a more modern style idle air control valve. Some refer to it as the GM or LS style but the IAC I used comes from a European Ford Fiesta application and it bolts straight to the throttle body with zero modifications or adapters. The original EEC IV style IAC works well for tens of millions of Ford products since the early 80's, but it is my opinion that Holley has not put any real effort into making it work correctly with its Terminator X hardware/software. I believe there are limitations in the Terminator X's hardware that is not able to properly control the Ford IAC like Ford intended. Holley made it kinda work, but has shortcomings and workarounds leaving all of us foxbody owners salty. Other videos showing the stock foxbody IAC compatibility workarounds, 1D table's on top of other 1D table videos are all afterthoughts in my opinion. The IAC I'm installing has the same functionality as one from the LS series of engines, and Holley knows how to make GM sensors function properly as the foxbody kit already includes GM style ECT and IAT sensors. You can immediately see how well this IAC works after the first turn of the key. If you perform this upgrade on your own car I think you will be very pleased with the results.
The items I used to this conversion are:
Holley Wiring Kit: 558-420
Idle Air Control Valve: 58-ISB-7427 (There are many suitable substitutes. Some cheap, some better)
Idle Air Control Valve connector: AC628 (There are many suitable substitutes)
After performing this modification you will also notice the the P Term and D Term adjustments on the IAC Settings page now actually do something.
The IAC valve I used is so cheap and works so well, it's sad to think that Holley does not include it in their original (but discontinued) Foxbody Terminator X computer kit. Offering it in stand-alone kit form as an upgrade would be a welcome sight. It's so cheap to do that Holley should have simply included the $13 IAC valve I recommended into their foxbody kit and ran two extra wires, instead of trying to trick-fuk the stock ford IAC into doing what they wanted it to do. The way Holley did it also used up one of the four Terminator X outputs, leaving you with only three. All with shoddy and non-descript instructions.
One thing I need to amend is the selection of IAC Control that I used at the 15:38 mark. I learned the acronym for the one I used is for GM Lsx, DBW(Drive By Wire). It certainly does not have Drive By Wire. I have since selected the plain "GM LSx" option and it has not changed anything as far as I know. I just feel better about it not being on the DBW setting in case it tries to do anything funny in the background that I'm not aware of at the moment.
Please throw me a like if it worked for you. - Авто та транспорт
Just did mine best mod for terminator X . Anyone who says it does not work is crazy much better drivability and start up. The idle comes down very smoothly now and no surge.
The stock Ford IAC works great actually. The only advantage to this is to gain an output back
Nice and easy to do, fixed my idle issue instantly. Started right up and man it’s a relief to start it without it dying especially on cold starts. Sweet video👌🔥
I am definitely doing this to my fox. Thanks for the step by step and part numbers and all!!!!!
Mr Fox’s abroad! You have a fan in south Texas! Thank you sir for taking the time to make this video! I have a build supercharged 331. I have been struggling with surging and stalling when I try to return to idle. This cheap fit did it. Idle so much better now.
Same issue with my car as well
Thanks for putting this video together! Will be doing same thing to my car.👍🏻
Nice and easy. thanks for showing us. I had the hanging idle when I first set mine up but a couple tweaks and never had it again. I do like how your rpms drop fast though. Also you have an open output now that you don't have to have it assigned for the ford iac!
I thought about this mod but I have had everything running great for a while now.
Setting up the e85 sensor now.
Great video!
Great looking notch man! Thanks for the vid.
Thanks for the video
I ordered the same parts !!
Followed the guide and my car started up just fine and idled perfectly 😂. The Terminator x would just not play nice with the ford iac valve before. My issue was cold starts and trying to move the car the rpm would just start surging even dying at stop signs until the car was at operating temp. Haven’t gotten to try the car more then just down the street though due to rain :(.
Anyway, thanks! Good vid!
new subscriber...lovin the video..very helpful...just takin notes before i put my holly terminstor x in my mustang..good to know theres alot of love for the foxbody mustangs,..
Great video! Thanks!
Great video - thanks well done
2024 Update for the 550-937 Ford MPFI kit. This kit comes with the 4 wire plug and all GM sensor plugs. Just swap the B1 and B8 wires in the J1B to make it a GM IAC compatible and buy the Ford Fiesta IAC. I should have waited to buy those until after the kit arrived. If you have an older Fox body kit you probably have to wire it and get the plug.
Very cool video
I have run a Terminator X in my supercharged h/c/i foxbody for a couple years now and am really happy with it but have had a couple minor things around startup and idle that have annoyed me (three slight surges every time on startup before idling steady, a couple surges as I would put in the clutch coming to a stop before catching itself and idling rock steady and the occasional hanging throttle in a parking lot where I would have to wait for it to decay down or shut the car off to reset). My research had me suspecting that the change from a ford iac to gm or chrysler style stepper iac may help but never got around to it until now.
I was about to order the Accufab iac adaptor for a foxbody and was researching the additional pinning of one of the connectors and running wires to a four wire plug for a steeper style iac when I came across your video with a stepper iac from a ford application that bolts right on to a foxbody throttle body without an adaptor. I can't believe I had not seen that anywhere before. I only found one other video that came out around the same time and no other mentions on any of the forums or fb groups.
I promptly ordered the necessary pieces and just installed last weekend. Car fired right up and immediately noticed how much more control the stepper iac gave me over the ford style. I did make a throttle blade adjustment and some tune changes to dial it in and find what the car liked but it starts easier, no more surges at startup or when I put the clutch in and low speed drivability, especially when cold is noticeably improved.
Thanks for the great video, much appreciated!
Loved the video. Very clear step by step.(love that). Unfortunately in my case it went the opposite way. I actually ended up having a surging problem after changing to this iac when the engine warms up :(
Why did you perform this modification if you were having success with the original IAC?
@@Mike-FoxsAbroad wanted the better response and it was finicky. (Oh and it made that humming sound like yours did). Was hoping it would fix all the bugs the original iac had.
I'd be inclined to think that you have something else wrong with the tune or the car making the idle surge so severe.
sweet video man i just bought one im glad i came across your video saved me money i almost bought the accufab adapter so i wana thank you for that!....going to start my install this weekend....
One thing I need to amend is the selection of IAC Control that I used at the 15:38 mark. I learned the acronym for the one I've been using is for GM Lsx, DBW(Drive By Wire). It certainly does not have drive by wire. This weekend I'm going to try the plain "GM LSx" option and give that a try and see how it performs. I'm not sure there is any difference but I'm just intrigued if things could be even better than what I initially recommended and have been using.
@@Mike-FoxsAbroad so are you having issues or you just want to see if it can get better ?
@@tinosantiago1790 No issues. I've done about 400 miles since performing this modifications. Simply trying a change since learning what DBW means.
@@Mike-FoxsAbroad good morning was just curious if you tried the plain GM LSX option and if there was any difference compared to the one you recommended the first time??? thanks again bro.
@@tinosantiago1790 Yes, I did it to both my car and Johns car. No perceivable change. I just feel better about it not being on the DBW setting in case it tries to do anything funny in the background that I'm not aware of at the moment.
I ordered the 550-937 non foxbody harness in December, it just showed up today. It's going in a Falcon, so I didn't need the under seat ECM bracket and probably won't run a TFI distributor. All the connections are for GM sensors. So this mod won't be necessary in my case or future purchasers, since the foxbody specific terminator x has been discontinued.
The title of this video is Foxbody Terminator X, so if you have a different version of Terminator X this video was probably not going to work for you.
very nice ..im sick of hanging idle ...ok its just when engine is cold but anyways ...this is pretty cool with the Stepper..this is a Ford Fiesta IAC..I live in Costa Rica so I have to send that stuff down here ..so it will cost me around 110 $ with shipping and tax ... but ill give it a try ..
I've also found that many timing tables that you find online have too much timing in the high vacuum transition between 2500ish rpms and back down to idle. The IAC will be at its idle settings but the high timing will not allow the idle to drop any further causing it to hang. Reducing the timing in that area can help prevent a hanging idle. You may need to have a laptop going while driving and see what the timing is when it hangs up. I've found when that happens, reducing timing in 5deg increments it in those cells, then smoothing the timing table can help immensely.
during driving i dont have any problems its just after cold start ..and not always...y already ordered all the parts ...gona give it a try ..spent more money for other stupid non working stuff .. @@Mike-FoxsAbroad
the humming is just the hz setting its set too. I've seen some run them as high as 800hz and they buzz alittle.
Pretty simple like you said they did a horrible job in this area. They did nothing to address the way ford did there IAC
Hello ..yesterday I got all the parts for the change ..easy job.. its not like in your vid .. but hanging idle is gone ...engine had some backfire in the first time ...let it warm up and went for a drive ..its getting better .. need to adjust a little ..thing is ..its so damm hot here all the time ..there is no real Cold Start because its always like 34 deg Celsius at day time and even hotter in the sun...have to find the right spot ..when car is warm everything works fine .. maybe its a Cam thing too ..? .I run the F cam ..
Idle and low throttle drivability tuning I believe is the most challenging aspect of playing with a cars computer. It's not easy to figure out and each car is different.
made some adjustments today and very happy with it, went down down to 850 idle and all fine ......@@Mike-FoxsAbroad
Great video. I ordered the stuff except the iac. The one you used isn't available but the ac628 one is available but twice as expensive. Would the ac628 one work is it the same just more money?
I only ever tested the one I gave the part number for and there seems to be a dozen or so suitable substitutes. I wouldn't worry. Give it a try and it will probably work just fine.
is that the factory ford throttle body in the video?? did you have to change the TPS also? I'm waiting for my terminator x universal ford kit to come in now and a little confused on what will plug in and work and what won't!! your car and installation look great !! appreciate any advice..
It's a Ford 65mm throttle body. It was on the Cobra intake manifold when I bought it. I modified the Holley harness to accept the stock TPS connector from the old factory harness. That way I could simply replace and plug in a new TPS sensor without modifying it in the future.
Did you set the range to the ford tps between 350-400?
I tried many different settings. The frequency of the PWM settings correlates to the audible sound coming from the stock IAC. It kinda works but I simply believe the Holley ECU does not have the muscle it needs to properly control the stock IAC. That is just my opinion based on experience. I'd love to hear from a Holley engineer on the subject.
Excellent Video... Off to EBay.. Also you did'nt mention the old Ford IAC wiring. Just leave it in place & unplugged I assume?
Yes, I just tucked it under the coolant rails.
Any idea if Holley connector 570-211 would work with this IAC? Looks pretty similar and it's already included with the new foxbody terminator x kits, would just need to be pinned differently.
Yes, it looks like it would work. I have no experience with the newer Ford Terminator X kits brought to market since Holley killed the original one.
I think I will do this but it's there a way to use the existing Holley wires going to the factory iac?
You can but it wouldn't make sense and be more trouble than it is worth. You need to buy the extra wire kit anyways. Also the wires for the current IAC would require an additional removal tool as they will not come out of the big connector without one. Then you would need to cut the current connector off the IAC end and still run two new wires. All the time making sure you are not mixing up the wires when you start repining them.
Have you utilized any additional tables to get a more controllable decay rate so the car doesn't either go into cruise control from too much IAC hold or too little and the RPM's fall like a rock when trying to drive smoothly?
I tried the 1D table video that was put out there. No perceivable difference in my car even after a lot of TPS resetting and adjustments. I'm not going to tell anyone how to manipulate the software in efforts to get something working that should be basic functionality. Workarounds just are not very efficient. Holley Terminator X is all about LS technology. They even included an LS style ECT and IAT sensor with the fox body kit. The foxbody compatibility aspects are all an afterthought in my opinion. Installing the LS style IAC valve just makes all of the standard Terminator X software work as advertised. It's so cheap to do that Holley should have simply included that $20 IAC valve I recommended into their foxbody kit and ran two extra wires, instead of trying to trick-fuk the stock ford IAC into doing what they wanted it to do and using up one of the four outputs.
@@Mike-FoxsAbroad Couldn’t agree more. I’m at 10k miles with mine so far. It’s been awesome except for this one minor thing. I have 3 different advanced tables for my IAC control. Kind of a waste honestly.
@@madevilmustang2824 In the near future I'm going to attempt to utilize the electronic speedometer output of my TKX, to try and build a feature where the idle will be raised a bit when the car is still in motion. Not sure if the input is compatible with the sensor yet but I'm going to do some more searching and testing. It may be a waste of time but I'll probably kill a few days tinkering when I'm stuck inside this winter.
Did your wiring harness come with the fox body iac plug?
If you are referring to the Terminator X harness? If so, yes.
Just wondering. With stock ford pwm did u adjust the hertz settings? I was told in the iac settings for ford 5.0 pwm it should be set at 315 frequency. Did any one try that?
Yes, if you look at around the 15:30 mark you can see the old settings before they were changed.
I have mine set at 315hz and it works flawlessly without any custom tables. a lot of people don’t spend enough time on the timing table which can cause the idle to hang or stall. if you have 30 degrees of timing when it’s trying to idle down there’s only so much the IAC can do. just my .02
I can’t find the pig tail
is there any confirmation this works with the universal MPFI harness?
Sorry. I have no way of knowing as both car's I've done this to used the foxbody specific harness.
Great Video! I'm definitely going to switch mine. Do you have an email? I have a few questions about your startup parameters.
Any feedback on this mod? Has it changed or improved while driving? Thx
I have nothing negative to say about it. It was nicer downshifting as the rpm’s wouldn’t drop as much. I believe the P term and D term values actually do something now vs the stock IAC barely being functional. In my later videos I explain that the MSD dual sync distributor took a shit on me and left me stranded. Took a few weeks to get a replacement from the states. Since it’s been running again I haven’t been able to get many miles on it due to work and weather.
Well I have my parts on order. I am really hoping this helps my cars return to idle better. So this means you have freed up an output. Have you made any plans for what You will do with it?
Just to confirm, you did not use the Holley Terminator X plug, you used the GM plug and just ran the wires to the pin outs. I'm install a 937 Kit and running into issues with the lack of sensors with the kit.
Yes, this frees up the 4th output that Holley dedicated towards Fords IAC.
Of course your engines idling properly you have an idling at 1000 RPMs! Is there any particular reason you chose to idle @1000 RPMs rather than something a little closer to the factory RPMs?
The engine was stone cold man. That’s the way it’s supposed to be. As it warms up the rpm’s drop and it can be whatever you program the Terminator X to be.
I can not find that IAC anywhere. Any suggestions..?
I don't know what to tell you. I put that part number into eBay and there are loads of them available.
@@Mike-FoxsAbroad I found it. Part #SMP-AC628 if you wanted to add to your video. I believe it's made by standard.
I'm sorry, It's a DTS part number 58-AC-628 I purchased through ebay.
Holley Terminator x is badass problem free reliable efi.
I can't find the idle air valve on Amazon. Do you have a direct link?
I ordered mine off eBay as they were the only ones that would ship it to the UK.
AC628 is the IAC. The brand Standard uses part # AC628 but it's rather expensive. I went with the DTS brand, Part # 58-AC-628 A lot of these ship from China and it's about a 19 day process. The one I ordered ships from the US so it will only be a few days.
When you put any of those part numbers into Google at least 10-12 different interchange parts numbers show up. There is no shortage of them but the price has risen a bit since I made this video.
@@Mike-FoxsAbroad anyone that has it for around $16 is sold out. I ened up paying $35 after about an hour of searching. The Standard brand even through my local parts store showed their cost was $114 but they couldn't get one.
It's a voltage thing .. ls runs on 12v Ford runs on 5v.. holly set to 12v
this actually comes up as a Ford Fiesta Ecosport iac? lol
Totally cheap aftermarket iac on it to start
Which IAC are you referring to? The Fiesta style one that we are installing? Or the new Foxbody Motorcraft one that I removed?
@@Mike-FoxsAbroad i didnt see a ford stamp anywhere on the one you took off. Maybe i looked away when you showed it. I know theres a setting or calibration, whichever term you prefer, that lets the stock ford one work perfect. I forget the channel i watched that explained it. And it may be a newer video then when you posted this. Ford iacs have always given me grief on a stock computer car running mods, or just a calibrated maf. So i was happy to see the video that helped me. Im just not a fan of cheap aftermarket parts, or amazon parts. Ive had too many problems with them. So i try and stick to oem or denso or delphi or stuff like that. Latest problem part ive encountered twice in a year on my own car, and two 94 lightnings of my buddies i supercharged, were the new red msd coils. Junk. Both died in under a year. My car running stock itnition, and the two trucks had btm msd units. Put motorcraft ones back on, and good to go. If i missed it im sorry, but that one that came off didnt look factory even the way it looked visually.
@@Mike-FoxsAbroad i will add, you do have to use a laptop to fix the ford iac parameters. All of which coulda led to your valve whining or buzzing with key on car off
@@dondagy9109 Yes, it was a brand new Motorcraft IAC. I used the cars original IAC first with poor results, then paid near $90 for the new Motorcraft one and it was no better. So I went down the alternate road of the Ford Fiesta style IAC. I never got the chance to test, but I wonder if the sound of the factory IAC would have changed if I would have altered the frequency of the 300hz setting in the Holly software. I’m thinking that’s where it was coming from. Hollys weird way of controlling the original Ford foxbody style IAC is dodgy and causes issues. I think it’s just a limitation of the hardware in the Terminator X. But the Term X is designed around LS sensors so using that style of IAC makes all the stars align and the idle control then works as it should.
@@Mike-FoxsAbroad fords iac is linear, most are steppers otherwise. So im not sure if the 300hz pertains to a linear iac. Usually hz is for pulse with modulation, which is steps. Change the hertz, and it changes the size and aggression of the steps. I know once you set the iac to ford 5.0 in the options on the laptop, you still have to change it from stepper to linear. I would also reset the throttle blade before doing the final learn on the iac. Usually on a stock modified 5.0, you have to add a bunch of throttle blad, and less iac input to keep idle wavering down.
Holleys fox terminator product was such a fail. We deserve a class action lawsuit
Why don't you just buy the Holley GM IAT, IAC, and ECT. THEY connect right into the Holley 550-937 harness. No modifications necessary. Plug n play. I have 550-937 kit.
Because when I made this video, those options were not available from Holley. I had one of the first original Foxbody Terminator X kits that hit the market. Things have matured over the past year and a half since I made this video.
Don’t you need to repin the 937 IAC PLUG to make it work correctly when using the fiesta iac valve?