Need to adjust Idle on FRPP 70mm T/B!!! (ASAP)

Discussion in 'SN95 4.6L Mustang Tech' started by BlackenedSVT, Mar 11, 2006.


  1. BlackenedSVT

    BlackenedSVT Active Member

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    Ok well maybe i'll try buying a TPS today and seeing if that will fix the problem. Also, i never bored/ported the Throttle Body. Its still "stock" for an FRPP 70mm T/B. The only thing i ported out was the plenum. I also air blasted, brakecleaned, air blaster, brakecleaned, air blasted & air blasted some more before i installed that plenum. So there can't be any metal shavings anywhere...

    Intake gaskets MIGHT be off, i'm pretty sure they are not, but if by next weekend all else fails, maybe i will recheck the gaskets. Dont think that is the problem, nor do i think that would affect the idle or hanging RPMS.
     
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  2. BlackenedSVT

    BlackenedSVT Active Member

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    Ok i will do this test when i get home later.
     
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  3. jstreet0204

    jstreet0204 Active Member

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    Try backing the adjustment screw on the throttle in quarter turn increments and see if the voltage drops. Count how far you backed it out so you can return it if it doesn't work. Take the plate you made off of the IAC valve until you get it fixed. You need everything functioning to correct your original problem, and the IAC mod that everyone refers to, restricts the functionality of the IAC.
     
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  4. BlackenedSVT

    BlackenedSVT Active Member

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    Ok i'll take the IAC restrictor plate off later tonight...but back WHAT adjustment screw off?? Want to take the pictures i have on the 1st page and repost them with an arrow to what you are talking about? If you mean the throttle positioning screw...my car doesn't have one, only electronically controlled through the TPS

    Please clarify



    And as an update: i drove the car 20 miles to school and back again and no check engine light came on yet...but the RPMS still hang and idle is still at 1500. I turned the AC and heat on MAX for 2 minutes, both while idling and then while driving. Just trying to help the computer re-learn. Dont know if its working :shrug:
     
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  5. BlackenedSVT

    BlackenedSVT Active Member

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    Hey i just thought of another possible solution that im going to try out anyway tomorrow:

    - Do you think any of those vacuum lines are supposed to have screwdriver-tightened clamps on the ends, to ensure the seal??? I didn't take any off the stock plenum, but i thought i'd try putting them on and see if that fixes it.


    (also, i have not been able to go outside and check the TPS yet, i'm getting some dinner, then i'll report back to you guys....by the way my check engine light came on again :( )

    where the hell is SVT TECH when u need him!!! :p
     
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  6. SilverGTV8

    SilverGTV8 New Member

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    You don't need clamps on the plenum.

    I wouldn't go playing with the TB set screw until you try and just unplug the IAC plug while the car is running. It should drop rpms to the point of stalling. If it does then the TB is set correctly. If it doesn't(rpms stay up) then that is probably the cause of it all.

    Check the TPS, check the TPS. You are asking for help but you have yet to do what is asked.:rolleyes:
     
    #46
  7. BlackenedSVT

    BlackenedSVT Active Member

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    dude im getting to the tPS!! give me a min! lol im trying to cook dinner :rlaugh: And if you read above you'd see that i DID already disconnect the IAC while the car was running. The car puttered down like it was going to stall, but continued running.

    So i dont know what TB "set screw" you are talking about, but i did the IAC unplug test, and that was the result. Later tonight i will go take out the IAC restrictor plate i have installed, and then i will test the voltage on the TPS while disconnnected from the T/B and see if i can get .99v. I already priced a new one and if the problem IS the tps, its $40 shipped.

    I'll get back to u guys in an hour or so.

    oh wait, i also heard that when you want to recet the PCM, you not only disconnect the battery for 10min, but you also need to go inside the passenger side kick panel and disconnect the harness going into the PCM..... now that doesn't make any sense to me why someone would disconnect both...but is that true?
     
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  8. SilverGTV8

    SilverGTV8 New Member

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    Never mind the TB set screw. That is not going to solve the problem you are having if the car puttered down.

    As far as reseting the PCM, just disconnecting the battery will do it. I have never heard of pulling the PCM cable.
     
    #48
  9. hotdog71

    hotdog71 Member

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    Disconnect the battery wait for about 10 mins then reconnect battery and DO NOT touch the gas for 15 mins the PCM will re-learn.

    Your RPM will hang around 1200-1500 like mine did when I swapped to 75mm BBK TB&P and slowly drop durning the learning process to around 850 RMP which took about 15 min, and problem solved.

    good luck.
     
    #49
  10. BlackenedSVT

    BlackenedSVT Active Member

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    ok wait for clarification:

    - after reconnecting the battery and NOT touching the gas for 15min...are you implying the car is running. (ie: you reconnect the battery, and then start the car and let it idle for 15min)??

    - And during your "learning process" u mention, which takes 15 minutes, is that idling? or driving the car?
     
    #50
  11. jstreet0204

    jstreet0204 Active Member

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    There is a threaded back stop on the top left corner of the TB. The throttle lever should be hitting it when it is completely closed. There should be enough on the end sticking out the back to grab with some small vice grips if there isn't a slot in it. THIS IS NOT the correct way to set the idle, but if it has been tampered with, it may not be letting the blade close far enough.

    The bottom line it you need to get that voltage down between. .99 and .97 volts to fix it. Otherwise the PCM is not going to be able to learn to idle correctly.
     
    #51
  12. hotdog71

    hotdog71 Member

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    Yes, from cold engine start the car and DO NOT touch the gas peddel and wait for car to reach FULL operating temperature then turn off engine and restart, then you are good to go:nice:
     
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  13. Shiroelex

    Shiroelex There's nothing worse than aut Founding Member

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    When you disconnect the battery to reset the PCM, while the battery is off, hit the brakes a few times, to get rid of any residual current. Get rid of any 'mods' as far as the intake goes, like that IAC mod, and center the tps. Make sure the throttle body butterfly is shutting all the way, and after 10 minutes, reconnect the battery, and start the car. The computer has to be cycled a few times to get the curve down. I think it's like 10 drives? Something like that. Run some errands around town after the reset, and see what happens.
     
    #53
  14. BlackenedSVT

    BlackenedSVT Active Member

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    Ok i just got home and this is what i did right away, so this is my current situation:

    I parked the car, popped the hood and removed the IAC, i then took my IAC "restrictor plate" mod off the car. and put the gasket back on and bolted up the IAC, and threw that restrictor plate aside.

    Then with the key in the car and the key ON, but engine off...i checked the TPS while connected. It was still 1.05 volts (guess it went up somehow, becasue last night i left it at 1.03v). So i then DISCONNECTED the TPS, but there is still power going to it....and with the tps disconnected from the throttle body, but still connected to the harness, the voltage read: .45v so the TPS is still good im assuming..

    I currently have the TPS out of the car, with the battery unplugged too. The car is just sitting whiel i have the TPS up in my room.

    I'm about to port out the screw holes in the TPS to give me more room to play with and HOPEFULLY i can get it down to .99v when plugged back in. If this doesn't work im out of ideas :(

    I'll report back later tonight after dinner when i port it out and put it back on and test the voltage. Thanks for any and all help guys :nice:
     
    #54
  15. GTR_Stang03

    GTR_Stang03 New Member

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    UDTbadcarma, I have done this a million times. Settle down and listen. Hotdog71 is right on the money! You need to follow his instructions precisely:
    Make sure engine is cold!
    Disconnect Battery for 10 mins.
    Reconnect Battery.
    Start Car.. BUT DO NOT TOUCH THE GAS PEDAL AT ALL!!! NOT WHILE STARTING OR DURRING STARTING!
    Leave your feet outside the car..lol.
    Let the car warm up to operating temp. (when you hear fan start).
    Then shut off car.
    Now start car. Your computer has adjusted to the T/B.
    If this doesn't work...Throw the Plenum away and get a BBK plenum.

    B. Jensen
    RLI Performance
     
    #55
  16. BlackenedSVT

    BlackenedSVT Active Member

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    ok ANOTHER update...i didn't want to wait until dinner. so i ported the screw holes and put the TPS back on..

    Got it to read .98v!!!!!! close enough for me!! :D

    So the TPS is set to .98V and locked back on tight, and the IAC is at stock form, with NO restrictor plate mod on it.


    Now i have to go to the gym, so ill let my car sit and get cold and come back later and do the above that HOTDOG and GTR_STANG said above.

    Thanks guys, i'll keep ya posted.
     
    #56
  17. jstreet0204

    jstreet0204 Active Member

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    This will not work if the tps voltage is too high. The pcm needs to know where closed throttle is.
     
    #57
  18. jstreet0204

    jstreet0204 Active Member

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    Good that you got it within range. Just double check to make sure the blade is closing all the way.
     
    #58
  19. BlackenedSVT

    BlackenedSVT Active Member

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    Ok i did this to the "T" and this is the results:

    After starting the car back up after reconnecting the battery, the RPMs still hang and the idle is still at 1500 =( Keep in mind this is with the IAC restrictor plate mod OFF, and the TPS corrected to .98v currently. Also, the CHECK ENGINE light is back on :( probably the same "vacuum leak" code...

    So im guessing i just have to be patient now and wait it out, for the computer to relearn everything?

    Unfortunately the test didn't work too well, but the car sure does accelerate nice with the 70mm T/B and ported plenum!!! Definately can feel a kick :nice:



    EDIT:
    I also want to add that i did not check the throttle position. I mean it looked fully closed when i was installing it, so im just assuming that is fine. The Throttle Positiong scew, setting the placement of hte throttle blade should not have been messed with, and im just assuming that it wasn't. So after a week if all else fails, i'll check it AGAIN, but i really dont think its the problem at this point.


    At this point im just going to drive it for a week and will report back around then with an update. If anyone has anything else to add, please do
     
    #59
  20. BlackenedSVT

    BlackenedSVT Active Member

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    bump for the morning crew
     
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