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One article says .90 to .95 volts.. Another says .98 to .99 volts Does anyone know for sure which one of these is correct?
 

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You need to see around .95-.99 volts in the throttle closed position and around 5.0 volts in the WOT position.
 

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With just the ignition on right? I put it at .98 .99 closed with the ignition on.. is testing it at wot necessary if it is I'll do it .. Should I reset the idle also? Or do you think I might have a hidden vacuum leak. It's running ok it still searches for idle intermittently. Btw already replaced iac,TPS, and cleaned throttle body..
 

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With just the ignition on right? I put it at .98 .99 closed with the ignition on.. is testing it at wot necessary if it is I'll do it .. Should I reset the idle also? Or do you think I might have a hidden vacuum leak. It's running ok it still searches for idle intermittently. Btw already replaced iac,TPS, and cleaned throttle body..
Yes, with the ignition key turned on.
It is a simple matter to check it at WOT.
Just open the throttle to WOT by hand while you are reading the voltmeter.

Here is what my Mustang Performance book says.

Once you have your voltmeter connected, loosen the two screws securing the TPS and turn the ignition switch to the "RUN" position.
Carefully rotate rotate the TPS (This is assuming that you have an adjustable TPS or you have modified the stock one.) until the desired voltage reading is achieved. (Usually between .98V to 1.5V.), then tighten the screws.
Sometimes you will have to loosen the screws and try again as the TPS will often shift when tightening the screws throwing off the setting.

The exact voltage you adjust your TPS to will require experimentation.
Fuel pressure, injector size, camshaft overlap and virtually every other engine modification has a considerable effect on the TPS setting.
It is best to start out with a setting of .998 volts, then experiment.
Small adjustments go a long ways, so test in small increments, generally .05 volts at a time.
Remember to readjust the setting every time you make a significant engine modification.
 

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Thanks you have been a God send I truly appreciate all your help...
No problem, I enjoy being able to help fellow Mustang owners. :good:
 

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You need to see around .95-.99 volts in the throttle closed position and around 5.0 volts in the WOT position.
WOT does not need to see 5.0 volts. In my experience, setting the TPS close to 1v has caused idle surge and stalling issues. The ACTUAL range is 0.7v-1.0. When I tune cars, I prefer to split the difference and set them between .8v and .9v. This leaves some "wiggle room" for voltage fluctuation, which can cause a car to actually register a TPS voltage that is too high for "base voltage".
 

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DoubleInfinity said:
WOT does not need to see 5.0 volts. In my experience, setting the TPS close to 1v has caused idle surge and stalling issues. The ACTUAL range is 0.7v-1.0. When I tune cars, I prefer to split the difference and set them between .8v and .9v. This leaves some "wiggle room" for voltage fluctuation, which can cause a car to actually register a TPS voltage that is too high for "base voltage".
You want it under 1.00 but specs call for as close to .97-.98 as possible. Go any lower than .9 and you start affecting wot voltage which isn't good. Btw wot voltage should be in the neighborhood of 4.5-4.6 volts. You should never see 5v unless you're hitting the 5v source wire.
 

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WOT does not need to see 5.0 volts. In my experience, setting the TPS close to 1v has caused idle surge and stalling issues. The ACTUAL range is 0.7v-1.0. When I tune cars, I prefer to split the difference and set them between .8v and .9v. This leaves some "wiggle room" for voltage fluctuation, which can cause a car to actually register a TPS voltage that is too high for "base voltage".
I understand that.
Go back and read my entire post.
It says "around 5.0 volts" and another parts says "The exact voltage you adjust your TPS to will require experimentation."

What works for you on your car may not necessarily work on everyone's car, hence "in your experience" that is what works for you.

The trick is to find what works best with your individual combination.
There are no set values that work perfectly for every car.
 

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Discussion Starter #10
Right now I have it at .98 .99v. And it still has a little surge I am adjusting in .2 volt increments... How many miles if any should I get in between adjustments to let the ECM learn
 

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Right now I have it at .98 .99v. And it still has a little surge I am adjusting in .2 volt increments... How many miles if any should I get in between adjustments to let the ECM learn
Well that may be debatable.
Previously everything I had read said 20-30 miles for the ECU/ECM to relearn, but I read recently in my Mustang Performance book that the ECU/ECM learns and adapts very quickly (a few minutes or even less).
So with that in mind it may only take minutes to see a change.

Until I find more or better information and/or experience it myself, I kind of agree with the ECU being able to learn very quickly. It would have to, to be able to adjust for the frequent changes in day to day operating conditions and scenarios.
 

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Have any of you actually seen the code in the CBAZA strategy? WOT is not designated by a certain voltage. The ecm reads the TPS voltage at the time the key is turned on, that value is then stored in the memory. WOT is then triggered when the TPS voltage is increased by a value of 3.13v (j4j1). This value is adjustable and can be set by tuning the ecm.

To the writer with the surge. Set your TPS back near .9v and perform a full and proper base idle reset. I'd bank on the surge going away.
 

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the only problem with that "article" is that setting your base idle to anything other than factory spec, which is around 575-600 RPM, can cause idle hang, stalling, and surge.

ESPECIALLY in the SN-95 cars (like mine)
 

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Discussion Starter #17
I still have to do the resistor configuration to bypass the EGR tonight/tomorrow once that is done I'll try these to see if it cleans up the idle. I'll repost on here to let you guys know how it goes.
 

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DoubleInfinity said:
the only problem with that "article" is that setting your base idle to anything other than factory spec, which is around 575-600 RPM, can cause idle hang, stalling, and surge.

ESPECIALLY in the SN-95 cars (like mine)
You can set it wherever you prefer, I've seen them both high and low rpms mentioned from reputable sources.
 

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You can set it wherever you prefer, I've seen them both high and low rpms mentioned from reputable sources.
setting the RPM higher than factory spec will cause the car to learn that at idle, it uses zero IAC duty cycle. When taking your foot off the gas at higher RPM's, this can cause the car to stall out.

Stop reading magazines, and listen to the people who do this for real.
 

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Have any of you actually seen the code in the CBAZA strategy? WOT is not designated by a certain voltage. The ecm reads the TPS voltage at the time the key is turned on, that value is then stored in the memory. WOT is then triggered when the TPS voltage is increased by a value of 3.13v (j4j1). This value is adjustable and can be set by tuning the ecm.

To the writer with the surge. Set your TPS back near .9v and perform a full and proper base idle reset. I'd bank on the surge going away.
the only problem with that "article" is that setting your base idle to anything other than factory spec, which is around 575-600 RPM, can cause idle hang, stalling, and surge.

ESPECIALLY in the SN-95 cars (like mine)
I've never seen the code. Is it available somewhere and can you make sense of it without some type of decoder?

What you are saying makes sense, but I have a hard time understanding why this info is just now coming to light.
I have literally read hundreds of articles, bought numerous books and researched high and low for information and I have never ran across any explanations similar to yours.

I also can't understand why the EEC-IV would have so much trouble adapting to a difference of a few hundred RPM, when it is so adaptable in other ways.

If you have further information, I would love to see it.

Thanks,
TH
 
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