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'99 & up Upgrades and Aftermarket - 7.3L Engine Upgrading or adding OEM or aftermarket equipment to your 1999-Up Super Duty or Excursion with 7.3L Power Stroke diesel engine. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.

Thread: Maybe if I ask about AIC in another way... Reply to Thread
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  Topic Review (Newest First)
09-28-2016 09:51 AM
blue99stroker The same place that lists the guide sells a idle controller for only 70 dollars.

Dfuser Ford 7 3L Powerstroke Auxiliary Idle Controller Elevated Idle Control | eBay
09-28-2016 09:18 AM
StockKnocker Tom, you could post a duplicate question in the pre-97 PSD forum as well. Or if there's ever an ambulance at your local scrap yard, grab the AIC module and mess with it. Your air intake heater only turns on below a certain temp with parking brake engaged, so maybe linking to that would work, but not sure, I removed mine for more air flow. It's controlled by the 2nd relay next to GPR. Stay warm, Buddy!
09-28-2016 04:15 AM
dieseldogtom Thanks again StockKnocker:

I sure do "hear ya" about the old days in the winter cold and a Chiltons book!
Hell, I didn't even have a tarp & a Kerosene (bullet heater) back then to help
warm things up a bit. You will probably appreciate what I am about to write....
Some people (99.9% of all woman) and I don't know how many guys, Will never
know all those rotten feelings you can get when you are out there at midnight
with some major portion of your vehicle ripped apart (usually seeing stuff you
never knew was even in there), laying all about you on the frozen ground,
Damn wind picking up in speed, Drop light casting as much shadow as light,
And you knowing you are only just beginning this job and cannot stop till it's
done because it's your only transportation, except for the motorcycle you will
be riding to the auto parts store first thing in the morning to get everything you
found that needs to be replaced. Just hoping it warms up a little bit that day and
that you can figure out how to get it all back together! .... Sound Familiar? LOL, NOT!
Anyway, After all this posting of photos & text of this (not really complicated) relay design AIC,
I have read some other posts (mostly on the 6.0L IIRC of being able to find just this one
wire in some bundle under the dash that's capped off (forget the color right now), And
tapping it into some other 12 volt source (watched a guy do it in a youtube) where he
used the parking lights as the source voltage. Just tapped this one wire and it idled right up
when he turned on the Parking lights! Oh, had to press the E-brake too. Wonder if that's
an option in these Vans? As in maybe they do have some of the Ambulance wire harness's
built into them as they come down the line. Maybe they don't know till later what Van
will be pulled off to go to be an ambulance package but that part (wires) is standard in
the wiring harness.
Another question that will probably never be answered.
Yeah, I read & responded to that "dropped the live wire" story and fried the PCM on his neighbors truck.
It came off as sounding Negative to me but I guess he was just trying to (send out the warning).
Since YOU linked me to it, You might have read my post (over there). I was kind of (flip) about it all.
HE dropped the relay.
HE messed up...
The design his neighbor gave him "worked great".
Why doesn't he give out some of the detailed answers to the questions I have asked?
He seems like he must be a pretty bright guy to have done all that electrical work, (Well,
up until the bonehead move dropping a live circuit). But he must know all about how this
part of the system (throttle TPS & IVS & PCM...) works. Why not answer some of the specific
questions asked? No, All I get is *WARNING* And telling me not to do something I think
most people working with an electrical wiring/relay system already know... To be real careful
not to short live wires to ground or you might FRY Something like the PCM. No S%@# Shirlock.
Guess I am still just frustrated not to have received any useful information on this thing so far.
So I just keep adding to this thread to bump it back up and see if someone (New) has anything
of relative importance to add besides, Just buy it from ..... DDT
09-23-2016 09:23 PM
StockKnocker Tom, I really want you to succeed with a better high idle, that's why I posted the other link. I can't really help you more than that because I don't have any experience altering the 5 volt system. I've only done diagnostics on it when needed. The vans are a weird combination of OBS pre-97 trucks, 99-03's, and tight space engineering! I'm sure you'll get it done.

The only reason I mentioned the spare computer is that's exactly what happened years ago to another intelligent guy who was putting one together. He was doing some kind of testing and his daughter came in hollering, "Supper time!" and it scared him. That caused him to jump and when he did, he cross-contacted some wires. After some more testing, he realized he fried the computer! Funny now, but probably not that day!

The lack of replies from other guys who have done this is probably because most of them have moved on to newer trucks and later forums. Good news is that there's still quite a few guys on here that are like PSD encyclopedias and willing to pass that knowledge along first hand, for free!

I'm grateful for that every time I think about an under dash wire fire that melted the harness in one of my first trucks! I spent 2 cold winter weeks alone with a greasy Chilton's book in the driveway! Boy, did I need the internet that time! I'm glad you're posting your progress for the next guy who wants to build his own high idle! Cheers!
09-22-2016 01:05 AM
dieseldogtom Here is the chart for a 2008 superduty if that helps anything
09-21-2016 11:05 PM
dieseldogtom Thanks StockKnocker.
The more I study the charts that have been posted about the 5 volt supply to the TPS
and the various resistance values (and accompanying LOWER voltages) , I just really don't
see what or why the system I have posted should cause a PCM burn out. For all the guys
that seem to have done this (in their own way) and seem to know a lot about this, I don't
get why none of them choose to comment on my schematics. I know they are not drawn
in "official" electrical diagram fashion but (if you ask me) they are a hell of a lot more detailed
than ANY OTHER DIY , AIC instructions I have read!
As I understand it the IVS is nothing more than a 12 volt on/off switch. That's the EASY one.
The TPS is described as a basic potentiometer. Charts supplied for 2008 year vehicles show that it's
a 5 volt PCM supplied voltage and resistance values between (OPEN CIRCUIT to 510 Ohms) create an
OUTPUT voltage to the PCM of between 0 & 4.4875 volts).
Does NO ONE here have information as to if this is the same (volt numbers) that other (older)(2003) vans work?
I'm still really at a loss here. I have seen guys go into GREAT DETAILS about various electrical components
and (pulse wave returns...) of various parts of the PCM and what signals it needs to get and at what pin number...
But MY AIC alternative DIY project seems to escape anyone's examination for input or errors in design?
Has anyone ever really read the other two or three DIY options and REALLY understood just what they were describing?
I have, And I don't understand them AT ALL!
MY design (and schematics) give you a very clear (picture) of how this can be done.
All I have asked for on this forum is for answers to some basic questions. Because I do NOT want to go
to the local wrecking yard to find a spare PCM when I attempt this project. That's not the way I do things.
I get ALL the information UP FRONT! I will be 99.9% certain my design is correct and will function without causing
any major harm. I'm not going to throw 12 volts through the 5 volt TPS circuit! But it would be nice to
have conversation back & forth about how the system works. There are a few basic questions I would like answered.
One would be a confirmation of the TPS on a 2003 van still using a 5 volt PCM supply?(Color codes would be nice).
Another would be....At IDLE, Is it an OPEN CIRCUIT (IE: No voltage to PCM return side pin)?
I ask that question because it (looks) as if the 2008 example chart has an alignment problem in the rows of
voltage/RPM/Ohms. But at the TOP is says (OPEN CIRCUIT) It leads me to believe that (much like the IVS) when the pedal is in the relaxed IDLE position it sends NEITHER a 12 volt (from IVS) or a .06875 volt (from TPS). Can't understand any other reason "OPEN CIRCUIT" would be printed on that chart at the top (IDLE) area.
So as you can see there are some pretty BASIC questions that need clarification.
There are a few others but since there seems to be no response to these I won't bother posting any more.
It's really to bad because I think this is a GOOD DESIGN and I think it would be easy for others to duplicate with not more than $20 worth of materials. And I KNOW the schematics are more self explanatory and detailed than ANY of the others I have seen out there. Maybe I just need to join some OTHER forums. I had thought this one to be the best and have the most knowledgeable people on it. I hate to think I was wrong? DDT
09-21-2016 04:41 PM
StockKnocker Tom, if I were you, I would check the local wrecking yard for a backup computer should something go haywire! With that said, let's commence feeding the bears! Here's another thread that might help out since it is a van: Homebrew High Idle -
Homemade High Idle Control - Ford Truck Enthusiasts Forums
Good luck!
09-16-2016 10:33 PM
dieseldogtom Here is the unit I made up but never installed. Sorry for the photo size. Have not figured out (or taken the time) to figure how or why some photos load a thumbnails & some do this. DDT
09-16-2016 10:17 PM
dieseldogtom Thought I would bring up this old thread of mine just to see if I would get any new information. I was looking at my schematic drawings for (my) DIY AIC. After having looked at and read what some others had written out or the electrical schematics (they) had provided for their DIY AIC's I have to admit I think I did a pretty good job of explaining & showing EXACTLY how it could be done. Even if your an idiot like me! Unfortunately I never got around to actually installing the thing. I did put it all together in a work box and attached all the wires to the relays leaving pigtails with identifying labels. (Then, Life happened & other priorities took precedent). Anyway, I started looking at my schematics again for the IVS & TPS modifications to be made with a couple of relays, a toggle switch & a couple of pots. (Not more than about $20 worth of parts). I also started looking back over this thread and one or two others I was posting/asking with people questions about if they saw anything fundamentally (wrong) with my set up... Also a few questions of deeper electronic details about what the PCM (expects) to see for voltages to make this project work correctly... It was/is interesting to look back and see how many advised me to just buy a OEM Ford AIC ($300 range) or the one offered by Dfuser (currently $79.00).
Even though I already did all the work putting together MY DIY DEVICE, at the time I was really interested in seeing my project through. Though quite a bit reluctant to cut into & redirect the wires on my throttle pedal and risk either it just not working or worst case, Burning up my PCM somehow. Without any further positive comments or encouragement and a few lingering questions that needed answers from someone more electronically sophisticated than myself, The project is left incomplete. With my renewed interest of installing an AIC in my vehicle I decided to take a look at the (close) to plug & play Dfuser option for $79.00.
Then I saw I could look at the instructions to install it. I downloaded the 2 page document. The first page is the instructions. Seems pretty straight forward. The color codes for the OEM wires (as I expected) didn't match what my vehicle has. That's probably not to big a deal. I am hopeful that I could get answers to that.
And that you do not have to cut any wires (just crimp/tap) into them is nice to. Then I decided to start to read the second page. You know, the legal stuff. I wonder how many people that buy these things really ever took the time to read that second page and understand just what it really says/means. Aside from the (typical) warnings that it's an aftermarket product and (they) can't be responsible for how (you) might install it or use it, And therefore cannot be held responsible for any liability/damage... I get that part. Most of the stuff we buy have warnings like that. But read closer and see that the (device) is also NOT warranted for as one line says... "respect to fitness, merchantability and consequential damages". That's kind of an important LEGAL definition. "fitness for a particular purpose" and "fitness for merchantibility" are legal terms and (usually) a product being sold IS REQUIRED to meet those legal definitions. If you are selling a hammer (for instance). It should be designed to meet it's expected use of being able to drive nails. It's "fit for the purpose" as well as "fit for merchantibility" (meaning, fit to be sold in the marketplace....
Sure I get that if you smash your finger with the hammer or use it in a way it was NOT designed for, that's not the manufactures fault and they should not be liable for damages in such situations.
Now, I am NOT saying Dfusers product does not work. I am NOT saying it does not work very good. I am wondering though why I would be better off spending $79.00 on a (ready made device) that the maker feels the need to include legal language (that if you read carefully), essentially means even if you wire it up correctly, It could still do any number of (damaging things) and (they) would not have any liability for!
The question becomes....Is their product really any better than mine? Is there design really better than mine. While I freely admit I DO like that it hooks up without cutting wires (only tapping into them) and that it very (possibly) IS a better design. I see there are also some things that make me wonder....It says...Here...I will just cut & paste it....
"Note: You must click the knob to the off position to be able to drive the vehicle. Also in most cases you also need to shut the engine off after using it and restart when the module is off for the ECM to unlock the pedal. On some vehicles with the engine running it requires that you press the accelerator pedal and then turn it on. This method should increases the idle as it should."
This all sounds a bit inconvenient. I'm pretty sure the FORD AIC don't require shutdowns. But then the FORD units are $300! Not $79.00
This all brings me back to MY DIY, AIC design. I would like once again to post up my schematics here and ask what hopefully some of you guys, that are way smatter than me, think as to if there is something (wrong) with a system like this and how you think it might interact with the PCM when operated (powered up).
Some of my SPECIFIC concerns are..... If you happened to roll one of the potentiometers all the way to one side of it's limits for either resistance or open circuit, Would it just likely make the engine stall out and maybe set a fault code OR is it possible or more likely to damage the PCM? I would think the advantage of having the two adjustable pots. is that you COULD fool around with them to get it so the one mounted through the dash will operate in the PROPER (RPM/Voltage) ranges between it's full deflections from counterclockwise (IDLE) to Clockwise (Slowly rolling up the RPM's). I choose those two pot. values (50K and 5K) based on research I have read from other DIY instructions for AIC's. There is also information (Charts) posted for resistance values applied against the 5 volt supply the PCM sends to the TPS and what RPM levels those various resistance's will result in. It seems the (system) works between .0875 & 4.4875 (feed back volts to the PCM) to produce an RPM range between IDLE of 680 rpm & a Maximum of 2400 rpm, using resistance values of between 43K ohms & 510 Ohms. So I guess another question would be if those potentiometers seem like they would (if wired correctly) result in output voltages in the range mentioned above? I'm pretty sure there is a fairly simple formula that can be applied to determine if a 5 volts supply and lets say 1.6K Ohms , would result in a voltage drop to 3.6875 (or should I say a voltage drop of 1.3125 volts)? This according to the "CHART" for a 2008 7.3 (things might be different for a 2003. But I believe they are all still working in those same basic ranges. Color codes of wires are likely different. And it might be a reversal of high RPM = low volts or Low RPM for High volts. Not sure if or why they would change it but there seems to be no end to changes made as the years pass. Anyone have any constructive criticism or productive information to add? DDT

EDIT: One thing I should change in the schematic.....I have the (wiper) as it's called, wire & internal to the TPS contact , making contact with what I would assume is the HIGHER voltage side of the coil in the TPS. (it's towards the LEFT close to the side the 5 volt FEED line enters the device). This would NOT be the IDLE position as the higher voltage going out to the PCM would be the signal for HIGHER RPM's. So that's just something I noticed and really is not all that significant. Just thought I would mention the mistake before anyone else did...LOL
05-03-2014 10:47 PM
Maryland dieselnick Ok,Clint Eastwood had a Smith and Wesson Model 29.It is a .44 Magnun.Clint preferred shooting the milder .44 specials through it.or his character did per script.
My statement".you won't unwind that mission" meant that you are wound up and n a mission that is all and would wager that honestly you would agree.
As stated earlier you you know my feelings about safety.Maybe you will get the answers you desire and more surprises after it's running in gear.You seem to have a pretty strong grasp for the electronic thing and I respect that,I really do.I don't know how strong you are on the diesel/Pwr.train,the PCM and it's strategies that you are tapping into.Something in there can be your surprise .
Now I dropped back in for one clarication,two response to your question and three commenting on your surprise you foun and how I believe there are more surprises.
Again I respect the knowledge you do have and I hope your project turns out the way you want.
05-03-2014 06:31 PM
dieseldogtom I have found one thing I should point out that differs from what I have written. Regarding the grounding of the relay coils to the emergency brake. I see there are 2 wires that run to the e-brake switch (which makes scenes and they do still appear to be ground wires.) BUT what I have discovered is that BOTH wires create a ground when the ignition is OFF. When the ignition is on, you need to locate the wire that only grounds when you apply the e-brake. This is also a good reason to wire the power supply to the toggle switch to an (ignition ON ONLY power supply) as is suggested in all the other AIC write ups. MY wire colors to the emergency brake switch are BLACK and GREEN/RED trace. It's the Green/Red trace that is an OPEN circuit when the ignition is on. Thereby creating the (safety) of not engaging the relays UNLESS you apply the emergency brake (at which time the ground circuit is (MADE) and allows the relays to work. SO...Connect your relay ground wire to the GREEN/RED trace from the emergency wire switch.
05-01-2014 11:48 PM
dieseldogtom Well Cobra, that just seems like all the more reason not to spend the big bucks on a factory unit.(even they don't quite work right from what you are saying). But no I have not looked for a wrecking yard Factory unit. I bet they still want plenty more than I have invested in this one AND I am sure a wrecking yard unit will NOT come with any paper work. But it's an idea at that should this project fail.

I'm still looking at the Official Ford chart showing the Ohms values and associated RPM's and voltages that cause those RPM,s (but that chart is dealing with a 2006 and I believe voltage through Factory AIC units). I hope others will continue to possible look at this thread and make constructive comments about what they see in the schematic and maybe even download to their computer and make adjustments to it if the feel it needs to be done in a different way. Maybe a better explination of the reasoning for the two pots. and how one is used to set the (base line RPM's) and which value pot. (the 50K or the 5K) should be R1 and R2 and weather the set up for each should start at the highest resistance output (lowest voltage output) and then enter the second pot. and in what resistance / voltage values should leave that one and travel back to the PCM for this thing to yeild the best results the first time. (instead of guessing and hooking it up all backwards and having to screw around with it). I bet one of the bright fellows on this site knows what I mean and could answer that or fix my schematic to be the best possible starting point.
Mostly I hope if some bright fellow see's this as a very wrong way to do it he will point it out so no one will duplicate it thinking it's a good plan. DDT
05-01-2014 08:34 PM
Maryland dieselnick You will not unwind that mission.
05-01-2014 08:15 PM
96Cobra I have the factory AIC on mine, and if you use it on a 2002 (my truck) & up, there's a glitch where the RPMs will sometimes jump to 2,800 RPMs, or something like that. You can get rid of that problem by adding a POT to the AIC. The paperwork that comes with the unit tells you what wires to use. Have you tried junkyards for a factory unit? It's just plug - n - play with it.
05-01-2014 08:10 PM
dieseldogtom One thing I believe I have wrong and didn't bother to change yet is on the TPS circuit, I would change the 2K resistor to a 5K adjustable with a knob just like the 50K. Seems the idea is to be able to fine tune that one to your specific vehicles quirks for the base line IDLE and then lock it into position. If for some reason you need to adjust it again in the future at least you don't have to go sorting through and re soldering different value resistors till you find one that gets it right. Just roll the knob a little and re lock it (tape or put some sort of sticky stuff that will hold it in position).
Here is what I have built up based on my schematic so far. That's two relays and the adjustable 5K pot. in the plastic work box. The second pot. can be seen with the (temporary) wire terminal attachments. (to be soldered on later IF it works out). Because I already had the relays, wire, terminals, solder... The only thing it has cost me so far is the two pots. (about $7.oo and the work box $5.oo) So I'm in this for about $12.00 plus my time.
Plus the satisfaction to know that if anyone looking at my schematic and explanation of how to do this might be helped and find it easier to figure out because of my (very unprofessional photos) that would also be a benefit.
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