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Here's how IAC's have worked on the Fords I'm familiar with. The throttle is typically very close to closed and set so the IAC's "plunger" is running at the midpoint of its travel enabling it to maximize its ability to control the idle speed via bleeding air around the throttles.

 

If I understood what you said in your post you are using the throttle cable to control the idle speed. I believe this may be your issue. You need a positive stop, the cable won't provide that. If there's nothing sticking I'm thinking that your butterflies are not coordinated with your IAC and you're bleeding too much air leading to high idle. If the butterflies stop is inconsistent you're going to have a hell of a time getting things dialed in.

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On 5/12/2021 at 9:47 PM, coffee break said:

Just an off the wall thought, any thoughts on lubricating the moving parts, shafts and hiem joints?

 

I could address that 

On 5/12/2021 at 11:43 PM, ashyers said:

Here's how IAC's have worked on the Fords I'm familiar with. The throttle is typically very close to closed and set so the IAC's "plunger" is running at the midpoint of its travel enabling it to maximize its ability to control the idle speed via bleeding air around the throttles.

 

If I understood what you said in your post you are using the throttle cable to control the idle speed. I believe this may be your issue. You need a positive stop, the cable won't provide that. If there's nothing sticking I'm thinking that your butterflies are not coordinated with your IAC and you're bleeding too much air leading to high idle. If the butterflies stop is inconsistent you're going to have a hell of a time getting things dialed in.

 

That's a peculiar point. Yes I was zeroing the throttle tension and setting idle with it. The idle screw on ITB's seems un-needed to me as butterflies should be fully closed if I'm using the IAC. So I've never adjusted it once I saw that they "close". This however makes me wonder, my car should idle fine without any throttle cable connected at all and I'm not sure if it does that. Fairly certain it either stalls or comes close to stalling while it's struggling. 

 

If I can't achieve idle without a cable at all then I either need to troubleshoot the IAC system or eliminate it entirely by setting the ITB's to be slighly open? Do I understand the two possible resolutions correct? Will that mess with ECU or will it throw the same amount of fuel regardless when it sees TPS at 0 and it doesn't care whether it gets air from ITB's or the IAC? I assume I can just leave it alone. 

 

I'll be further troubleshooting/waking up the neighbors this weekend. 

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V.

I'm an amateur at balancing ITB [but have done mine several times]

- I have AT power ITBs and a heltech ECU.  my ITB's have a communal connection to the fuel pressure regulator & internal MAP sensor of the ECU.

- There are individual bleed screws on the itb's and individual/joint butterfly stop adjusters. At idle/zero throttle there is a slight slack in my throttle cable to ensure butterfly's are fully closed. IIRC: butterfly's are adjusted to be fully closed and bleed screws were adjusted & balanced to maintain equal flow(suction) and the specified air flow through each horn.  I don't have an IAC but would expect this should supply the desired airflow bypassing the butterfly's.  I'm no physicist or engineer but assume that variability in plumbing/tube length/fittings/branch pattern, etc could also affect equal flow to each cylinder.  Have you tried disabling the IAC and just balance the ITB's & bleed screws with a manometer or synchrometer? 

 

good luck

p.

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1 hour ago, wemtd said:

V.

I'm an amateur at balancing ITB [but have done mine several times]

- I have AT power ITBs and a heltech ECU.  my ITB's have a communal connection to the fuel pressure regulator & internal MAP sensor of the ECU.

- There are individual bleed screws on the itb's and individual/joint butterfly stop adjusters. At idle/zero throttle there is a slight slack in my throttle cable to ensure butterfly's are fully closed. IIRC: butterfly's are adjusted to be fully closed and bleed screws were adjusted & balanced to maintain equal flow(suction) and the specified air flow through each horn.  I don't have an IAC but would expect this should supply the desired airflow bypassing the butterfly's.  I'm no physicist or engineer but assume that variability in plumbing/tube length/fittings/branch pattern, etc could also affect equal flow to each cylinder.  Have you tried disabling the IAC and just balance the ITB's & bleed screws with a manometer or synchrometer? 

 

good luck

p.

 

Hi. Thanks for the info.

 

I have not tried to balance anything yet. I've only bought a pressure measuring unit before the rebuild to get a baseline and to see whether they are balanced.

 

I'll be honest ECU and anything related to mapping and if/then command orders of the systems are a "black box" mystery to me. I understand how components work but I have no idea how they interact/have a handshake with the ECU and what it does in return. Never needed to question it. Now that I'm looking into my problem I'm learning a better understanding of the system which will allow me to come to a resolution.

 

It appears that me tensioning the throttle cable at idle is a problem. As I'm understanding now the car should idle without any throttle tension, whether by having air go past the butterflies directly or having the butterflies closed and having IAC/Bleed screws or similar provide the air.

 

When I will go back out I will test to see how/if the car starts without throttle cable. I will also make sure all the butterflies are shut completely by moving the idle screw out more. 

1) If it struggles to maintain idle with AIC on, I will unplug the line and give it more air only balanced by my finger on the intake port on air distribution rail.

2) Alternatively I will plug the AIC rail entirely and adjust the idle screw on the throttle bodies to keep them open, essentially eliminating IAC entirely

 

 

It's entirely possible that my tensioned cable at idle is the core problem. 

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Alright. Updates of the day.

 

I recorded the problem in situ. Cable connected and the rev hang. Forcing joints back in would bring it back down. I also unclipped the IAC hose and controlled the air by hand for a test of concept

 

 

 

This is where playing with the throttle cable set my idle and you can see by me releasing the pressure would cause it to stall. IAC was not picking up the idle with no throttle in put/cable tension

 

 

 

Here I measured the vacuum with the butterflies closed, due to the amount of hissing I heard earlier when messing with throttle cable. Not sure if they are supposed to be 0 when closed but they sure werent. 

 

 

Then I connected to the ECU and saw that I was having 10% throttle even with them closed. Again not sure if it's supposed to be 0 but thats where we were

 

 

So I did the last part of the plan. I plugged the IAC line entirely and bumped up the idle screw on the throttle bodies. 

 

I believe I achieved the expected success. Without the IAC involved at all, the throttle cable was free/lose at idle and the car maintained idle. Seemed a little harder to start and I have to give it a blip of gas to start but everything seems normal and no hanging. Drove it around today and will continue testing.

 

So in summary appears my IAC wasn't/isn't working or working well and I had to have had throttle cable tension in order to maintain idle which caused the sticking problems. 

 

As a means of at least temporary solutions I'm plugging the IAC line and running on ITB's idle air screw adjustment only. 

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Posted (edited)

Not sure why one butterfly still reads much lower vacuum vs others (7 vs 10) but I can troubleshoot that later. 

 

(sorry about iPhone rotating pictures for some reason)

 

Car parameters to start

76325E8A-FA26-4672-A444-C8AD8B8183E5.jpeg

 

TPS shows 10.8 at idle

 

EB09A167-256C-4ABF-877D-13FE000CAE71.jpeg

 

Idle settings (not sure what any of them do)

 

B9301218-8AD0-4B44-ABE1-FD0DCCF5F67E.jpeg

Edited by Vovchandr
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I suspect you need to re- zero the tps on ECU.  I wonder if the IAC isn’t doing anything ecause at 10% i doesn’t think it’s closed?

 

when I adjusted my ITB’s it affected the TPS reading (marginally) so I re-zeroed it to declare what 0 & 100% throttle are.

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Posted (edited)

From what I follow in the thread, you have a couple of issues. Here's what I'd do to get some kind of baseline where the car will idle:

* pick a base idle w/o IAC control that's a bit on the slow side

* set that idle with the engine hot using the idle screw

* balance the throttles and readjust the base idle (it's going to change when you balance the throttles, go for the smoothest slow idle with balanced air flow numbers)

* make sure the idle is stable and there's no interference due to the throttle cable

* now look at your TPS setting, if you don't know what the original setting was when the map was made you may have to do some digging in the fuel/spark/IAC maps to see what the mapper used. If you just want to cut and try dial the TPS to 0.

* the idle should not change (there's no IAC)

* now hook up the IAC and if things are close you should witness some form of idle control

 

I don't think ditching the IAC at this point makes sense, you may as well get it working. Worst case scenario you ditch the IAC and tune the idle with fuel/spark/coolant/air temp. It won't be as consistent as using the IAC, but it will work.

 

The trick here is I don't know what the mapper intended with the base TPS and IAC settings, but it looks like you have access to the Pectel unit so that's just time and patience reading over how the idle mapping was done.

 

Andy

Edited by ashyers
ps. Look at the IAC and see what the closed throttle window is, that will be useful when setting the TPS
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If you get totally bogged down PM me and I'll try and help out via Zoom. It's been a while since I've played with Pectel units, but I may be able to help out.

 

Andy

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@wemtd and @ashyers thank you both for the help 

 

looks like I'm not getting out of this without learning more about Pectel and what all the categories do in order to understand it better and find where exactly to zero out the idle TPS as well as looking at maps? Might have to message you for that one or take you up on the zoom offer @ashyers

 

 

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I think you're pretty close to getting this sorted out. It's just a matter of some adjustments, I don't think you have any issues with your parts or the mapping. If you poke around in the Idle Speed Control settings you'll likely find the info you need (TPS @ Idle and Idle Speed).

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On 5/16/2021 at 11:52 AM, ashyers said:

I think you're pretty close to getting this sorted out. It's just a matter of some adjustments, I don't think you have any issues with your parts or the mapping. If you poke around in the Idle Speed Control settings you'll likely find the info you need (TPS @ Idle and Idle Speed).

 

I'll look into it in the near future.

 

So far, the testing as is continues and so far no obvious issues. At least as a means to an end I'm happy with the 7 being operational so I can enjoy it when weather is good. I can tinker on down days and concentrate on other projects. 

 

Thoughts:

- The hang used to also happen when the car got hot/started to go above operating temp. So far neither happened. I've stayed at temp and haven't had any hang when hot. *longer testing needed*

- I've also considered that my WOT my not actually be WOT according to ECU. My zero throttle was off, worth checking if my full throttle is accurate

- Rebuild ITBs don't seem like night and day difference. If anything I actually feel like I might be down on power and I've had some strange noises/flat spots in the few times I've got on it recently. Requires more investigation and setup of the wideband to monitor A/F. 

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1 hour ago, Vovchandr said:

- The hang used to also happen when the car got hot/started to go above operating temp. So far neither happened. I've stayed at temp and haven't had any hang when hot. *longer testing needed*

 

 

If you were previously using the throttle cable to set idle rather than have it a little loose as you do now, that would make sense.  See my earlier comment about the shroud and cable expanding at different rates when hot.  If it does happen again when things are truly hot, check if the slack you put in the cable is still there.

 

-John

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17 minutes ago, JohnCh said:

 

 

If you were previously using the throttle cable to set idle rather than have it a little loose as you do now, that would make sense.  See my earlier comment about the shroud and cable expanding at different rates when hot.  If it does happen again when things are truly hot, check if the slack you put in the cable is still there.

 

-John

 

I agree this also makes sense. I think the combination of issues was a interesting case of compounding problems. Whatever was causing the car to run hotter (air bubble? etc), was also causing the cable to run hotter than normal, which was in turn causing binding while hot due to incorrect tensioning of idle by cable to begin with. 

 

As of right now there is ample slack at idle that is held by ITB idle control screw slightly propping up throttle bodies. I idle at about 1400 and still about 10% of TPS position at that point. I know it's not ideal and my idle should be 0 TPS but it works while im still figuring things out. 

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Another FWIW... I don't recall if this issue has been addressed and that is that possibility of vacuum leaks.

You can use carb cleaner to hunt with. A spray on an area like intake gaskets etc. and listen for a change in RPM.

Happy hunting.

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Posted (edited)
1 hour ago, coffee break said:

Another FWIW... I don't recall if this issue has been addressed and that is that possibility of vacuum leaks.

You can use carb cleaner to hunt with. A spray on an area like intake gaskets etc. and listen for a change in RPM.

Happy hunting.

 

Good idea as well. The runners from the vacuum "box" are still original 20 year old hoses. I did basic pressure test on them with blowing into the vacuum box but I'm sure that's not very thorough.

 

Updates:

 

Decided to get more serious about the tuning software and will share with the class.

 

*FULL DISCLAIMER* there is a chance that this monkey poking around on the typewriter at certain point in time over-wrote my original maps with one of the ones I found on the internet. It's highly unlikely (5%?) but stranger things have happened. I'm not sure how I would verify. I think you have to load a profile to start and I may have pressed the flash button years ago. More on that below. 

 

As I suspected, my WOT is not really WOT. At pedal to the metal I'm only at about 60%. Going to the ITB's and maxing out the linkages I'm at about 75%. I have to figure out how to change that. Not sure how drastically this effected my performance but I'm sure it was at least marginal. If WOT condition had it's own maps, that means I never hit them. 

 

Pretty pictures time

 

 

 

This is the welcome window that describes this loaded map. Time stamp 2002 of last update. Could be OEM?

 

1.jpg

 

This is a a closed throttle menu on top left. Not sure what it implies

 

closed throttle window.jpg

 

This is the open menu for the TPS sensor

 

errors.jpg

 

This is the IDLE SPEED CONTROL menu 

 

idle settings.jpg

 

Welcome window. Loads from ECU

 

main window.jpg

 

This is with what the car looks like on at IDLE - settings on the right. 10.6% TPS

 

Also shows the menu where I think I may have over flashed my ECU? "Load maps from ECU flash"? I'm sure I clicked it at some point a year or two ago (as well as today)

 

menu.jpg

 

All menus expanded

 

most open.jpg

 

Car running at idle

 

running.jpg

 

second main window.jpg

Edited by Vovchandr
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So now that I'm in over my head I'm going to have lots of questions.

 

If my ITB's were physically wide open but my TPS was only reading them at ~65% does that mean that I was running lean this whole time?

 

If so I'm going to have to escalate my time table for wideband sensor install.

 

Could this have been setup like this on purpose originally?

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If it was mapped with ~90deg throttle opening being ~100% throttle and you're getting ~90deg throttle opening at 65% throttle you'd be a bit lean and the timing would be wonky too!

 

Take a look at your base fuel map and see what it looks like. You could map a car so actual WOT is at 65%, but the only reason I could see doing that would be you're too lazy to sort out the throttle linkage travel. You'd loose a bit of resolution, but you could make it work.

 

If you disconnect the throttle cable are the throttles capable of sweeping the TPS from ~0%-100%?

 

Andy

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7 minutes ago, ashyers said:

If it was mapped with ~90deg throttle opening being ~100% throttle and you're getting ~90deg throttle opening at 65% throttle you'd be a bit lean and the timing would be wonky too!

 

Take a look at your base fuel map and see what it looks like. You could map a car so actual WOT is at 65%, but the only reason I could see doing that would be you're too lazy to sort out the throttle linkage travel. You'd loose a bit of resolution, but you could make it work.

 

If you disconnect the throttle cable are the throttles capable of sweeping the TPS from ~0%-100%?

 

Andy

 

I'll look at the base map over the next couple of days and see if I can make sense of it. If I share it here would that mean anything to you? I've never looked at a map in my life so until I understand it, it's just foreign language.

 

With cable or no cable my current full range of ITB linkages is from ~10 to ~75. I'm know sure if I need to change/adjust the TPS or reteach the ECU somewhere as to where the min/max setpoints are. My cable doesn't interfere with return to zero nor does it prevent full 90 degree. I believe I max out on a hard WOT screw stop on my TB at 90, but I'll double check. 

 

After more testing I'm also noticing a bit of a flat spot low in the RPMs in some gears when I get on it hard but thats likely another issue entirely. 

 

 

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