[stangage]

Here is a code snippet from the A9L. I checked against the cbaze (t4m0), and it is basically the same (slight difference in how the filtered TP value is done)...

The first part ensure that the TP is in range. Failure management is used if not.

The second part updates the relative close throttle TP value based on the filtered TP value.

I suspect this .99999999999999 volt myth will continue though.
Anyone read this group???

Code: Select all

3932  A372A230            ld    REG_30,$A2[REG_72]      ; 0x0122 = ITP                          Read TP input A/D value
3936  8BF27030            cmp   REG_30,$70[REG_F2]      ; 0x8eca = throttle_position_min        Compare to min value
393A  D306                jnc   L3942                                                           If less that min, jump
393C  8BF26E30            cmp   REG_30,$6E[REG_F2]      ; 0x8ec8 = throttle_position_max        Compare to max value
3940  D123                jnh   L3965                                                           
3942  A372A630      L3942 ld    REG_30,$A6[REG_72]      ; 0x30 = TMP1L; 0x0126 = RATCH          If TP out of range, set to RATCH
3946  3FA11C              jbs   REG_A1,BIT_07,L3965     ; 0xa1_7 = CRANKING,CRKFLG              Jump if cranking
3949  8BF78400A2          cmp   REG_A2,$0084[REG_F6]    ; 0xa2 = AM; 0x942c = IDLMAF            
394E  D315                jnc   L3965                                                           Jump if MAF > max idle air
3950  34C515              jbc   REG_C5,BIT_04,L3968     ; 0xc5_4 = TFMFLG                       Jump unless TP failure set
3953  A3F00230            ld    REG_30,$02[REG_F0]      ; 0x8c02 = ATIV                         Load initial ratch value
3957  C372A630            st    REG_30,$A6[REG_72]      ; 0x0126 = RATCH                        Store ratch value
395B  67F7820030          add   REG_30,$0082[REG_F6]    ; 0x942a = FMCTTP                       Add inferred TP from AM 
3960  D303                jnc   L3965
3962  BDC030              ldbse REG_30,#$C0             ; 0x30 = TMP1L
3965  A030AA        L3965 ld    REG_AA,REG_30           ; 0xaa = SEED3,TP; 0x30 = TMP1L

412C  C372803E            st    REG_3E,$80[REG_72]      ; store filtered TP to reg 3E
4130  890807AE            cmp   REG_AE,#$0708           ; 0xae = N                              Compare RPM to 450 rpm
4134  D10A                jnh   L4140                                                           If too RPM too low, jump to end
4136  8B72A63E            cmp   REG_3E,$A6[REG_72]      ; 0x3e = TMP8L; 0x0126 = RATCH          Compare filtered TP to RATCH
413A  DB04                jc    L4140                                                           If greater than, jump to end
413C  C372A63E            st    REG_3E,$A6[REG_72]      ; 0x3e = TMP8L; 0x0126 = RATCH          Update ratch with filtered TP value
4140  F0            L4140 ret

[cgrey8]

This is for sailorbob

[TripleBlackVert]

sure looks to me like it it taking the current value and storing it in RATCH.

that begs the question ... does it then normalize the TP relative to REG_3E in other places where it deals with the TP?

if they have that code there, my guess is they do normalize it later. but it is possible that they ran out of time and had to ship it before being able to implement that part. there is only one way to tell ... keep digging

[BobCat]

The .999V is not a myth......yes it will "adapt" for some functions but for others it will not.

[stang&2Birds]

The .999V is not a myth......yes it will "adapt" for some functions but for others it will not.

Pray tell. Please show either where in the code or spec you base that on.

Sorry, NO hardware or software engineer would have the EEC-IV architecture do something stupid like that. For one thing, other than the RATCH valued used to do WOT, it's the rate of change that is important!

The EEC-III had an adjustable TPS, a pure POS architecture, almost no code space, and was clearly one of the worse and most stupid architectures ever done for an EFI setup. Like the early Teves ABS systems, I point to that as "proof" of corruption in the NHTSA, . Both are dangerous to the owner and to the general public.

The vref, temp co, mechanical changes, and so on would make using the absolute value of something like the TPS would be massively stupid from an engineering point of view. Say what you want about the EEC-IV code and architecture, but it sure as heck was not done by fools. Yes, There are a ton of compromises in the algorithm, architecture, and so on! But, they are there because of code space, code execution reasons, and the Ford mandated cost considerations.

BTW: _Read_ the spec, and then just do a search on the raw TPS input. It's really that simple.

And, yes, the 0.999999v it is a ricer myth!

____________
Joe
Been doing this junk professional for what seems like forever.
My current project is for a high volume and cost sensitive product (yea, it's been a while - ~7 years). I had to fight tooth and nail and do a lot of justification to get a $1.50 part added to our design. Now, that will be one of the main advantages of our architecture.

[vristang]

The .999V is not a myth......yes it will "adapt" for some functions but for others it will not.

I too would like to see what you are basing this on...

From what I have found in the GUFB, the .9999v junk is myth.... probably carried over from eec-iii???

I am curious what you mean though,
jason

[Cougar5.0]

The .999V is not a myth......yes it will "adapt" for some functions but for others it will not.

Could you be just a tad more specific? What "other" functions are you referring to?

[stang&2Birds]

The .999V is not a myth......yes it will "adapt" for some functions but for others it will not.

I too would like to see what you are basing this on...

From what I have found in the GUFB, the .9999v junk is myth.... probably carried over from eec-iii???

I am curious what you mean though,
jason

Correct! The EEC-III is a JOKE. Although I don't know the internal political circumstances, I can say without a DOUBT that the the people/person responsible for the software algorithms was clueless and totally incompetent in that role! To be "fair", maybe that person was thrown into that position against their will. Regardless, the system/software architecture for the EEC-III was at a level that would've resulted in a failing grade for even a 3rd year engineering project.

Also, the EEC-III had an adjustable TPS because the EEC-III software was too slow, too small, and too simple, to do a "self calibration". IMHO, that is fine! I accept and understand about limitations (code, cost, performance, etc). *My* compliant with the EEC-III is the moronic fault detection and the possible EEC-III actions with a faulty sensor.


However, as I've said numerous times, *I* see the EEC-IV and later Ford PCMs as being fine when the limitations of cost and the knowledge at that time are considered. Yea, compared to the GM PCMs, the Ford stuff is pathetic. But, GM has also had "a few" (yea, right!) code problems over the years because of their complex algorithms. Considering the number of SD Stangs running today with mods and the age of the engine, sensors, and so on, even the initial EEC-IV code bases and overall system architecture is damn impressive for the ability of the time, the cheap cost of the system, and the desire to keep the software development costs low(er).

I'm in a similar situation today as the EEC-IV system. I have to decide on cost, features, algorithm risk, feature risk, development time, etc. I'm the sole digital person on this project (for both the hardware and software). There are a ton of real-life issues to consider. If I pull this off, I look great and I'll have an awesome bullet on my resume. If I do a moronic design like the EEC-III or early TEVES ABS systems, I end up never ever getting another consulting gig ever again since I'd get a "this guy mega sucks" type of referance from my current job.

So, again, from an engineering point of view, there is a huge difference between feature trade offs, and blatant clueless incompetent design when it comes to controlling real-life systems with real-life tolerances, wear, safety issue, reliability issues, costs, and so on.

____________
Joe

[stang&2Birds]

The .999V is not a myth

BTW: For future referance, when people say set the TPS to 0.99.. volts, those of us with EE degrees fall down laughing! Uhm, don't people realize that the sensor voltage is the EEC VREF voltage. And, that is only accurate to approx +/-2% (I forget the exact spec). And, VREF varies with engine load, alternator load, battery load/condition, temperature, sensor/EEC/actuator load, and so on.

The TPS is nothing more than a variable resistor (linear potentiometer). So, all it will do is divide the input voltage (in this case, the POS VREF) down by some amount. And, since the TPS is a simple wiper design, it has noise, wear, accuracy, contamination, and so on issues. So, at a 0.9v "setting", even if the TPS was welded into that position, the variance on VREF alone would result in a possible output variance of ~0.04v. Just 8-bits of sampling a 0-5V signal yields a resolution of ~0.02v (5V/256). All ADCs of that time (and even most today) have sampling bit/count noise. From what I remember, it's ?3? counts of noise on the EEC's ADC (actually, that's pretty good for that time and cost). So, even with a precision voltage referance that's good to 0.001v or better, the EEC will be reading approx 0.06v of noise on any input.

BTW: On ebay, you can get precision voltage referance/supplies that have resolutions of 0.001v or better for ~$200. Did I mention how I love ebay for "old" test equipment! Yea, I personally own 2 HPs precision voltage referance/supplies. FWIW: By far, the best deal for a precision voltage referance/supplies is the "old and out dated" HP 6112A. But, it's "only" accurate to 0.001v. :) (0.1% output voltage accuracy, +100 µV.)


Yea, the Ford use of VREF is another great example of a design trade-off to get a low-cost design. GM has long had (always had?) multiple isolated voltage sources for their EFI systems.

Fords use and spec of VREF has a lot of real-life implications. For one, it limits the max voltage that the EEC can reliably measure over all operating temperatures and conditions. So, that limits the max MAF voltage that a system can reliably measure over all operating temperatures and conditions.


Also, the physical changes in the mechanics over real-life operating temperatures (commonly ~ -10F to ~250F), make setting the TPS for that type of accuracy impossible. For "fun", consider the mechanical considerations in things like fighters or satellites. Earth orbiting satellites have temps that go from near 0K (~273 C, ~460F) to roasting in the direct heat of the sun (no atmosphere to protect them). I still say that space alien technology is used to allow our satellites to maintain the precision of some of their sensors and actuators! ;-)

______
Joe

[Frit]

The .999V is not a myth

BTW: For future referance, when people say set the TPS to 0.99.. volts, those of us with EE degrees fall down laughing! Uhm, don't people realize that the sensor voltage is the EEC VREF voltage. And, that is only accurate to approx +/-2% (I forget the exact spec). And, VREF varies with engine load, alternator load, battery load/condition, temperature, sensor/EEC/actuator load, and so on.

The TPS is nothing more than a variable resistor (linear potentiometer). So, all it will do is divide the input voltage (in this case, the POS VREF) down by some amount. And, since the TPS is a simple wiper design, it has noise, wear, accuracy, contamination, and so on issues. So, at a 0.9v "setting", even if the TPS was welded into that position, the variance on VREF alone would result in a possible output variance of ~0.04v. Just 8-bits of sampling a 0-5V signal yields a resolution of ~0.02v (5V/256). All ADCs of that time (and even most today) have sampling bit/count noise. From what I remember, it's ?3? counts of noise on the EEC's ADC (actually, that's pretty good for that time and cost). So, even with a precision voltage referance that's good to 0.001v or better, the EEC will be reading approx 0.06v of noise on any input.

BTW: On ebay, you can get precision voltage referance/supplies that have resolutions of 0.001v or better for ~$200. Did I mention how I love ebay for "old" test equipment! Yea, I personally own 2 HPs precision voltage referance/supplies. FWIW: By far, the best deal for a precision voltage referance/supplies is the "old and out dated" HP 6112A. But, it's "only" accurate to 0.001v. :) (0.1% output voltage accuracy, +100 µV.)


Yea, the Ford use of VREF is another great example of a design trade-off to get a low-cost design. GM has long had (always had?) multiple isolated voltage sources for their EFI systems.

Fords use and spec of VREF has a lot of real-life implications. For one, it limits the max voltage that the EEC can reliably measure over all operating temperatures and conditions. So, that limits the max MAF voltage that a system can reliably measure over all operating temperatures and conditions.


Also, the physical changes in the mechanics over real-life operating temperatures (commonly ~ -10F to ~250F), make setting the TPS for that type of accuracy impossible. For "fun", consider the mechanical considerations in things like fighters or satellites. Earth orbiting satellites have temps that go from near 0K (~273 C, ~460F) to roasting in the direct heat of the sun (no atmosphere to protect them). I still say that space alien technology is used to allow our satellites to maintain the precision of some of their sensors and actuators! ;-)

______
Joe

Wulp... since you obviously know everything and are so perfect at everything that you can laugh at everyone out there and that everyone but you is stupid as you are clearly indicating.... why don't you just rewrite all the code in the EEC IV for us, and tell us exactly what needs to be done and the perfect sensors to get ....

And of course, you should be able to tell everyone here exactly how to tune their cars perfectly first time as well... after all, we're not engineers so we're just stupid.

For your information, I tested an EEC IV by applying 13.67 volts to the MAF signal input pin and the EEC indicated that many volts. Just thought you should know, but of course I'm not an engineer, so I guess I'm in the stupid category as well LOL!

[stang&2Birds]

For your information, I tested an EEC IV by applying 13.67 volts to the MAF signal input pin and the EEC indicated that many volts. Just thought you should know, but of course I'm not an engineer, so I guess I'm in the stupid category as well LOL!

To be blunt, you're 110% full of it. For one thing, the EEC ADC just reads counts/value. And, that value tops out at ~5V. Also, any input over ~5.7v gets clamped by the chip - PERIOD. Have you even seen the chip spec? Clearly NOT!

I'm stating FACTS. I'm stating BASIC EE/CS FACTS. I'm not arguing about algorithms, what's the best way to do things, and so on.

If you don't want to talk FACTS, that's fine. But, don't think for a second that you can spew pure and total BS like the EEC CPU being able to read over 5V and people aren't going to know.

I stated WHY setting the TPS to 0.999v is a STUPID RICER MYTH THAT MAKES NO ENGINEERING SENSE AT ALL. I also stated WHY there are real-life trade-offs in designs. That's all, nothing more, nothing less. If you see that a personal attack on any ricer beliefs that you may have, I'm sorry. But, it's *not* my place to hold your hand and to comfort you because someone else LIED or mislead you.

If you do NOT want to know the TRUTH that people ARE LAUGHING AT YOU when you makes mistakes, or repeat RICER BS, I'm sorry. But, most people *I* know do what to know when they were LIED to, or made a fool off. Clearly, you seem to prefer to remain in the dark. That's fine, that is *your* choice. But, for *most* people, I'm sure that they do care.

_________
Joe

[stang&2Birds]

And of course, you should be able to tell everyone here exactly how to tune their cars perfectly first time as well... after all, we're not engineers so we're just stupid.

I don't get involved in tuning discussions. There are many factors.

Not being an engineer does not make someone stupid. But, arguing about a specific well-defined topic that a person doesn't have any knowledge, education, or background on is stupid.

Unless you flip burgers for a living, does that mean that I can kick you out of your job and from day one do exactly what you do, as well as you did it? If you think that some professions don't need degrees, that's you view. So, would let some person without any medical education do surgery on you? Well, when you depend on your EFI system to power your car, control RPMs, control the transmission, and so on. And, your ABS system NOT to activate for no reason at all and just slam on the brakes when you're on the highway, does that mean that the engineers that do the designs and architectures should be any less qualified or educated?

Or, how about when satellites that contain deadly material is sent up into space and can come falling down on innocent people if something goes wrong? Should those people doing that design be qualified or educated? Even when they are, things can still go wrong.

Excuse me now, I have to go call your boss and tell him that I'll be taking your place on Monday.
__________
Joe

[Frit]

So how does the EEC read VBAT???

Whatever, I know what I did and I know what the system recorded when I tested it and did the conversion to volts...

And if the AD cannot go over 5 volts and its hardwired to not do over 5.5 volts, explain why Ford hard coded an AD counter limit of FF00 which equates to aprox 15.9375 volts for the MAF... Its right in the code for the EEC. Did they just waste memory by coding in those checks?

Edited: Not stooping to insulting.

[Frit]

And of course, you should be able to tell everyone here exactly how to tune their cars perfectly first time as well... after all, we're not engineers so we're just stupid.

I don't get involved in tuning discussions. There are many factors.

Not being an engineer does not make someone stupid. But, arguing about a specific well-defined topic that a person doesn't have any knowledge, education, or background on is stupid.

Unless you flip burgers for a living, does that mean that I can kick you out of your job and from day one do exactly what you do, as well as you did it? If you think that some professions don't need degrees, that's you view. So, would let some person without any medical education do surgery on you? Well, when you depend on your EFI system to power your car, control RPMs, control the transmission, and so on. And, your ABS system NOT to activate for no reason at all and just slam on the brakes when you're on the highway, does that mean that the engineers that do the designs and architectures should be any less qualified or educated?

Or, how about when satellites that contain deadly material is sent up into space and can come falling down on innocent people if something goes wrong? Should those people doing that design be qualified or educated? Even when they are, things can still go wrong.

Excuse me now, I have to go call your boss and tell him that I'll be taking your place on Monday.
__________
Joe

Your amusing to read really, since your on here calling everyone stupid because of this and that.

Go ahead, do my job :D you made it clear you can do everything better than everyone else.

[cgrey8]

Guys, I'm all for a good debate and I like reading about them. But this has gone beyond debate into the realm of mud-throwing. I would suggest from now on that if someone doesn't see things your way, don't feel compelled to correct them or convert them. Just state your understanding and why. Let all others come to their own conclusions. If the person you happen to disagree with holds their belief for right, wrong, or indifferent, just let it go and agree to disagree. There's no need for the loaded words and emotion to affect a discussion. At least not in my opinion.

I say this because I really don't want this site to be a place where opinions can't be shared freely. I've been on other forums where you have to be ready to defend almost any post you make because of people looking to nit-pick everything you say and that's just not enjoyable to read or be apart of. Ok????

[Frit]

Guys, I'm all for a good debate and I like reading about them. But this has gone beyond debate into the realm of mud-throwing. I would suggest from now on that if someone doesn't see things your way, don't feel compelled to correct them or convert them. Just state your understanding and why. Let all others come to their own conclusions. If the person you happen to disagree with holds their belief for right, wrong, or indifferent, just let it go and agree to disagree. There's no need for the loaded words and emotion to affect a discussion. At least not in my opinion.

I say this because I really don't want this site to be a place where opinions can't be shared freely. I've been on other forums where you have to be ready to defend almost any post you make because of people looking to nit-pick everything you say and that's just not enjoyable to read or be apart of. Ok????

Sounds fine with me :D .

[sailorbob]

So how does the EEC read VBAT?

The battery voltage goes through a voltage divider circuit to create 'IIVPWR' so that it can be within the range of the ADC.

[patrickmx2]

Hi guys. I'm with Chris on this one. I can see some very intelligent discussion going on but we can all tend to digress. I'm interested in the 100% true way to set the idle, TPS, etc... I've read a lot of docs out there and I seem to have at least obtained a good idle under the hardest conditions.

My experience with electronics is limited to what I can tie together with my hands and wiring, etc... I cannot tell you why air bags don't deploy or why antilock brakes dont work or lock up.

A friend of mine was killed last week in a 2008 Expedition. The strong storms weakened a very old large tree. It fell in perfect (not for him) timing and leveled the truck from the hoodline back. It honestly looks like the truck exploded from the inside. The air bags never went off (useless in this case anyway) and even when the truck cleared the tree it still had enough momentum to drift off the road, went down a bank and slammed into another tree. At that time the front end was involved and was mashed up into the radiator support and buckled the hood (the first tree never contacted the front end). One would have thought the air bags would have then deployed, even though it was already too late.

My point? I'm sure there are some FACTS that could explain many aspects of what systems didn't deploy. Pure and simple I don't know of any vehicle that is designed to take an impact from the wipers up and rake the truck clean from the front seats back to the tail lights.

I know no one here is stupid or a moron. Please check the emotions at the door and explain the points based on fact. Don't be so quick to discredit someone's findings because I'm open enough to know that garbage in is garbage out and we all are capable of basing our findings on bad information, etc...

The only crime here is if someone has the truth and is withholding it for fear of being flamed. Now who ever has it, please cough it up :D

[Adam McLaughlin]

Air bags deploy when two or more sensors detect an impact. You can see these sensors usually at the corners of the vehicles, hence if the truck was hit at the cowl by the tree there would be no impact to detect and thus the bags would not have deployed.

Sorry to hear about your friend. That is a freak accident for sure.

Adam

[patrickmx2]

Well on my 1990 coupe the sensors are in the front but also there are some in the quarter panels ahead of the rear tires. I figure his truck suffered so much damage though that most of the systems were destroyed before there was time to activate them on the final tree impact.

When I say raked clean I mean literally down to the frame rails behind the front two seats. The rear doors, quarters, entire top, I mean it looks like a chassis with two front fenders and two front seats. His wife seated beside him survived.

So as far as electronics goes I'm dumbfounded how the math works in them sometimes. But now I can wire you for sound or do a nice EFI conversion.

[Adam McLaughlin]

Wow that is amazing. Someone must have been looking out for his wife; that is miraculous that she survived.

I think that the sensors ahead of the rear tires on your car are for the side impact stuff.

I have only played around with the crash sensor hardware a little; since none of my cars run this kind of hardware, I can say that I don't tinker with it much. I think that in theory you need a specific timing event between the two "crash" signals, but I can be mistaken because I am writing that from memory.

Where did this happen? Was this in Tennessee?

Adam

[Chris Mureen]

Sad news.....

Yes about emotions...many forums have ugly shout-fests but I have been very pleased that it doesn't happen here. Lets don't start now.

WRT the TPS, it sounds like what is being described is like how it is in the EECVs. However, there are two things that make it hard for me to accept.

1 - While I have a EECV, I tuned a few of EECV cars (A9L) and I remember one where it wouldn't go into closed loop until I dropped it below 1v. I am certain of this because I discovered it the hard way... several years ago before I ever heard that there was supposed to be a 1v limit.

2 - I was told by the guy who wrote the SCT software (David Posea) that the EECIV does handle idle voltage different from my EECV.

I should add that he also told me there was a limit point in the EECV also but it was pretty high, he recalled 1.2v. We use TPRel which is the relative TPS voltage after KOEO when the ratch setting calibrates TPS each time. What if the EECIV uses the same logic but instead of 1.2v the limit is 1v (or approx)? I crawled through the strategy doc on my car (CRAJ0) and could never find that documented, but I trust his knowledge.

YMMV

Chris

[patrickmx2]

Wow that is amazing. Someone must have been looking out for his wife; that is miraculous that she survived.

I think that the sensors ahead of the rear tires on your car are for the side impact stuff.

I have only played around with the crash sensor hardware a little; since none of my cars run this kind of hardware, I can say that I don't tinker with it much. I think that in theory you need a specific timing event between the two "crash" signals, but I can be mistaken because I am writing that from memory.

Where did this happen? Was this in Tennessee?

Adam

It was about 2 miles into the MS side of the TN/MS line of hwy72. This guy was married to the daughter of founder Bill Taylor of TCI Automotive. Bill Taylor sold TCI and later bought Memphis Performance. Also known as BTE http://www.bteracing.com/

He and his wife had just been to lunch and all the storms had passed two days before but this tree must have been damaged. They were going back to work when the tree fell into the road, a very massive tree. It wasnt windy or stormy at the time. No warning, just passing under it as it was falling. Sunny day too.

[patrickmx2]

--- Getting back into the TPS----

So is it fair to say that setting the TPS this way works? Because I have gathered that when you start the car the EEC samples the TPS to get a base.

This is how I do my idle.

1)Unhook the IAT
2)Pull the Spout.
3)Unhook the O2's
4)Adjust the idle set screw and tune so the car will hold an idle with the least amount of introduced air.
**I could elaborate more here but this is just a condensed version**
5)Stop and start the engine to see if it will crank and run, and idle.
6)Reconnect all the hardware

That's essentially what I have found to work. Typically when I'm done I can crank the car and remove the oil filler cap. That will introduce umetered air into the intake by means of the PCV and my engines will begin to shake, go lean and miss. If they idle up that usually means I am still too rich in my tune but by then I can notice the typical idle surge also.

[sailorbob]

As long as the TPS voltage at closed throttle is below the various self test min values then the eec will cope with it as all of the important TPS related decision processes use the relative TP value (actual TP minus closed TP values). If your TPS is reading between 0.95 and 1.0v then it will be fine as the typical failure value I've seen is 1.25v (in both eec-iv's and v's).

Regarding eec-iv vs eec-v handling of the idle, certainly the early eec-v's don't differ from the iv.

BTW the eec uses a 10 bit ADC so the resolution is better than described above.

[patrickmx2]

Typically I have found the current TPS on both my cars seem to be around .79 and .85 when I log. It depends on a few things like engine temp or if I've snapped the throttle with my foot a time or two and if the A/C is on, fans running, etc...

All of this is observed with no adjustments being made and just looking at it as time passes on. I've hardly ever seen them stay to the exact voltage I left them set at but within a few points from it. Usually always below 1v though but I didn't do that on purpose. It just works out to be this way from the idle setting method I use.

[Adam McLaughlin]

That is very interesting; especially the observed variance in the TPS voltage.

On my car I can push it down to about .8 VDC when I want to, but on the truck the lowest I can get that sensor to read is about 1.12 V even when I loosened the sensor mounting screws and twist the sensor to read a lower voltage.

I have never had a problem setting an idle with either, just so long as the throttle stop screw is adjusted to allow the engine to run slightly below the desired idle speed without the IAC being plugged in.

My experience with THIS practice has led me to believe that there is an observation made from the "ratch" position of the EEC when the computer is first turned on to run.

Adam

[Chris Mureen]

My experience with THIS practice has led me to believe that there is an observation made from the "ratch" position of the EEC when the computer is first turned on to run.

Adam

If the EECIV is like the EECV, then you are correct. The relative throttle position is set at key on.

Chris

[sailorbob]

Relative TP is not set at key on, the eec constantly adjusts the closed TP position downwards so that the various thresholds are not affected by the closed throttle value varying thought out the run.

[Adam McLaughlin]

Hey Bob,

Can you elaborate on that some more?

I believe that I am following what you are saying, but I would like to know more about the specifics of this operation.

Adam