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my iac valve stopped working so to get home i screwed w/ the throttle body stop screw and a bypass screw thats on the bottom of it. now i replaced the iac valve but my idle is off.(i know they are not adjustable i was trying to geet home) i found out that throttle body for 1995 tbird 4.6L was discontinued @ the dealer. to make it worst i made slots on the tps sensor trying to adjust it, now my transmission shifts differently.
does anybody have any specs on what the tps output should be @ idle? or
how to adjust the throttle body back to specs?
how to adjust the stop screw? isjust to prevent that that throttle blade slamming on the body itself? please help!!
 

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let the engine get up to normal operating temperature
open up the throttle via the stop screw so that when you unplug the IAC the car just barely holds idle speed (partially stumbling, but not shutting down)
plug the iac connector back in
with the key on, engine off, adjust the tps so it shows 0.97-0.99 VDC on the middle and lower wires
 

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my iac valve stopped working so to get home i screwed w/ the throttle body stop screw and a bypass screw thats on the bottom of it. now i replaced the iac valve but my idle is off.(i know they are not adjustable i was trying to geet home) i found out that throttle body for 1995 tbird 4.6L was discontinued @ the dealer. to make it worst i made slots on the tps sensor trying to adjust it, now my transmission shifts differently.
does anybody have any specs on what the tps output should be @ idle? or
how to adjust the throttle body back to specs?
how to adjust the stop screw? isjust to prevent that that throttle blade slamming on the body itself? please help!!

I don't remember where I got this procedure, it's for EEC-IV (shouldn't be much different than EEC-V), and I'm not trying to confuse you with a different procedure than what Guitar Maestro said, but here's what I have written down:


Summarized/Corrected Base Idle Reset Version

1. Clean TB with carb cleaner and nylon brush (toothbrush size). Engine off, fully open TB blade and spray/brush TB until all gunk and oil residue is cleaned.

2. Allow to dry, or close TB blade and start engine until it clears all carb cleaner fumes/liquid.

3. Let engine idle...if it doesn't, increase idle speed via TB stop screw until engine stays idling on its own.

4. Disconnect IAC valve, if engine dies repeat 3 with IAC disconnected.

5. Set idle speed to the lowest setting possible between 650-850 rpms with IAC disconnected. It is key to use the lowest possible to prevent idle surge, rolling, etc once the IAC is connected as follows.

6. Turn engine off, and reconnect IAC

7. With Ign On Eng Off, check TPS voltage output....if it's between .8vdc - 1.0vdc, it's OK. This voltage check should be done between the Green and Black wires at the TPS side connector as shown in the pic below....(-) terminal of the DVOM on the Black wire and (+) terminal on the Green wire.

8. Disconnect battery (-) for 3-4 minutes.

9. Reconnect battery, start engine, allow it to idle for 2-4 minutes to confirm setup,

10. If idle speed falls too low or stalls, increase idle speed via the TB set screw a little at a time.

11. Turn engine off for 20 seconds, re-start engine and repeat 9 - 11 if required.

12. Reconfirm TPS output is within the .8vdc - 1.0vdc range.......you're done!...

..no need to reset ECM KAM (reset computer) b/c the TPS minimum value used for idle control, is automatically reset by the EEC-IV every time the ign is cycled on-off for 20 seconds-on, and as explained in the next post

13. Allow a 10-20 minute "relearning" period under normal driving conditions (drive cycle).....now you're done.
 

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Discussion Starter #5
thanks alot for the replies! i'm going to try to adjust it today. it sound logical, because that's the way way it sounded when my iac valve went out as soon i would take my foot out the accelerator it would die out. i'm still worried about not being able to buy a new throttle in case mine some day takes a dump! is there any place to get this? or we just have to go junkyard hunting?
 

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Discussion Starter #6
i tried, but it didn't work, is like my iac valve dont work but is a brand new from napa.i warmed it up close the throttle till it just stays alive (400-450 rpm) turn key on (engine off) and plug iac valve back on. when i turn the car on made no difference it's still running 400-450 rpm. checked wiring (phisically, continuity and voltage)continuity is good, there's no physical damage tears or bare wires, but i'm not sure about voltage coming the cpu is around 3.26v. i'm going to try disconecting the battery for a while then try again see what happens. any ideas of what could be wrong? any way to reset the cpu other than disconnecting the batt.?
 

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if you're checking voltage going into the iac then that wont do anything...its a PWM signal, so you wont any useful info there...the voltage to check is at the tps...it needs to be just under 1vdc once you have set the throttle screw and the engine is just barely able to idle with the iac disconnected....if when you plug the iac connector back in, it doesnt idle at around 750rpms in neutral, then something is up with the iac
 

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Discussion Starter #8
OK! set tps @ 0.979 and did everything else again and nothing, i'm going to take the iac valve back to napa and exchange it maybe is defective.

i adjusted the tps but for now i adjusted the back to 750rpm thru the tb stop screw cause i got to go to work tomorrow. i'll continue once i get the part.

i'll keep you guys posted!
 

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OK! set tps @ 0.979 and did everything else again and nothing, i'm going to take the iac valve back to napa and exchange it maybe is defective.

i adjusted the tps but for now i adjusted the back to 750rpm thru the tb stop screw cause i got to go to work tomorrow. i'll continue once i get the part.

i'll keep you guys posted!
Sounds like a bear! Good luck with it!
 

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Had that happen on my '00 CVPI, drove it two weeks with a short piece of rubber tubing over tip of stop screw holding throttle open a hair until I got a new IAC for it, just replaced and removed tube.
 

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Discussion Starter #11
Had that happen on my '00 CVPI, drove it two weeks with a short piece of rubber tubing over tip of stop screw holding throttle open a hair until I got a new IAC for it, just replaced and removed tube.
i had that idea @ first, but the IAC was failing intermitently, so when i put that piece of hose and the IAC decided to work it would send my idle to the roof(1800-2000 rpm)
 

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i had that idea @ first, but the IAC was failing intermitently, so when i put that piece of hose and the IAC decided to work it would send my idle to the roof(1800-2000 rpm)
Mine started off like that and I would whack it and it'ld be OK awhile.

Then I tried cleaning it a couple times. I was working midnight shift and didn't want to work all night, then go to the dealer when I wanted sleep.

So finally when it stuck once, I slipped that piece of tube over the screw end.

Can't recall just now ... but it worked well enough that idle was OK with AC on, a hair high without it on so I either had defrost or AC on.
 
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