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throttle quirk

Discussion in '1st Gen. Tacomas (1995-2004)' started by Ridgerunner, Mar 25, 2008.

  1. Mar 25, 2008 at 4:18 PM
    #1
    Ridgerunner

    Ridgerunner [OP] Well-Known Member

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    I brought this up in another thread with no response. I get maximum power at about 8/10ths throttle-from there to the floor power slightly decreases. So I bent the throttle pedal arm to reflect max power at the floor..but I know in my mind it's never really full-open at the floor. Has anyone had this happen? I wonder is it a TPS issue or a limiter of sorts? I only open her up at freeway on-ramps occasionally-not a lifeordeath thing-just wanna tap the knowledge and see if there's a fix. Thanks
     
  2. Mar 26, 2008 at 8:42 AM
    #2
    Ridgerunner

    Ridgerunner [OP] Well-Known Member

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    Hey Phantom- yeah I gotcha- that's why I was wondering if it could be the throttle position sensor? I got no answers again so it's looking like I'm the only one with this dillema. Thanks for your reply!
     
  3. Mar 26, 2008 at 6:45 PM
    #3
    tacotoe

    tacotoe Pastry Chef

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    What year is your Tacoma ? Mine is an `01 and it still has throttle cables. I`m not sure what year they changed to the electronic throttle. I just purchased a new TPS after getting a PO 320 code but havn`t put it on yet.
    I can kind of relate to what your experiencing though. BTY the PO320 code never came back after cleaning the MAF and throttle body. TPS cost about 60 dollars.
     
  4. Mar 26, 2008 at 7:22 PM
    #4
    Ridgerunner

    Ridgerunner [OP] Well-Known Member

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    Hey T'Toe- yup mine's a 2001! Thanks for the reply..I've got cable too but we have throttle position sensors too. You made me think though- I bought a k+n oil filter and ran it for a while but I didn't like it 'cause I felt like it didn't do a darn thing.. but I saw some other guys on another thread saying that the oil can fluff off onto the MAF! Easy to clean was it? Thanks again Pal!
     
  5. Mar 26, 2008 at 7:36 PM
    #5
    Janster

    Janster Old & Forgetful

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    Everytime this topic comes up - I often think about exactly how the throttle-by-wire works.

    I've mentioned this before in other threads... In my 2004 Dodge Ram, you could calibrate the pedal *throw* simply by pressing your foot on the pedal (to the floor or desired position) and turn the key to ON. I used to set it halfway and it gave it more throttle response.

    I actually tried this on the tacoma and I didn't notice anything. I'm guessing Toyota doesn't have the ability to calibrate it.... or perhaps that we don't know how. ?

    Anybody know If we can do this on the tacomas? Any toyota techs out there?
     
  6. Mar 28, 2008 at 5:37 PM
    #6
    tacotoe

    tacotoe Pastry Chef

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    Yes, it was easy to clean( the hardest part was wrangling the rubber tube between the air box and manifold ).I bought two cans of cleaner one Throttle Body and one MAF sensor cleaner.Unhook both wiring connections, TPS and MAF. I pulled the rubber tube out of the way and laid a rag underneath the MAF (to catch excess) then just spray it off don`t touch it with anything because the wires break easy I`m told. Then basically do the same for the throttlebody ( I just cleaned the area around the butterfly). While your in ther, you might have someone depress the accelerator pedal to the floor and see what the pos. of butterfly is, should be about parralell I think. If not I think there might be adjustable at the cable, but not sure. Hope this helps. I wish I would have taken Pics. (sorry).
     
  7. Mar 28, 2008 at 5:51 PM
    #7
    Ridgerunner

    Ridgerunner [OP] Well-Known Member

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    Hey T'toe-don't need pics..your answer helps alot-thanks!
     
  8. Mar 28, 2008 at 5:52 PM
    #8
    glassdoc

    glassdoc Well-Known Member

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  9. Mar 28, 2008 at 5:56 PM
    #9
    Coreyjon

    Coreyjon Northern Alliance: Airlift Div

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    Phantom, with ours being fly by wire, there has to be an aftermarket solution (sometime in the future). It could be a inline magic box, a updated ECU Code. It would be great to be able to hook a computer up to it, drive around, and change it on the fly until you find the response you like best, and keep that.
     
  10. Mar 28, 2008 at 6:03 PM
    #10
    Ridgerunner

    Ridgerunner [OP] Well-Known Member

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    Thanks very much for the link Glassdoc..I can use it!
     
  11. Mar 28, 2008 at 6:07 PM
    #11
    tacotoe

    tacotoe Pastry Chef

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    I forgot to mention I took the air filter out and sprayed the wires from that direction. Might be able to see them better that way and not spray your filter. Oh, also the directions on the can say to let everything dry before re-assembly. Be sure to read the direction on cans too, incase I forgot anything else. Glad I could help ya.
     
  12. Mar 28, 2008 at 6:11 PM
    #12
    glassdoc

    glassdoc Well-Known Member

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    Here are the diagnostic values etc..
    page 1/1 http://www.deserted1.com/FSM/Repair_Manual/03tacoma/ss/sfi5vzfe/serdat.pdf
    I also think it was YotaTech that had a ongoing thread concerning the failure of the electronic throttle by wire, and one of their guys had step by step instructions on how to set the throttle position sensor in sync with the accelerator position sensor.. As they have to work with each other.. I'm trying to find the thread, but there are so many throttle body searches..
     
  13. Mar 28, 2008 at 6:29 PM
    #13
    Ridgerunner

    Ridgerunner [OP] Well-Known Member

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    Hey T'toe-I'll be super diligent believe me..no hurry here. Glassdoc I'm gonna check that second link later 2nite I gotta go get the Wifee. Thanks to you guys for all the quick knowledge on this one!
     
  14. Mar 28, 2008 at 7:22 PM
    #14
    glassdoc

    glassdoc Well-Known Member

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    Found it.. On TTORA.. Its a lot of technical reading but is good info on the throttle by wire..
    http://www.ttora.com/forum/showthread.php?t=13283&highlight=throttle+by+wire

    Taken from the posts:
    The interesting thing is how much the Throttle Position Sensor (TPS) and Accelerator Petal Position Sensor (APPS) interact. In the electronics it would seem they are in the same circuit, so that if you move one, it impacts the other. For example adjusting the APPS to a position my correct the throttle cut out can change the idle speed, moving the TPS to correct for this will electronically change the position of the APPS, possibly to where the ECU it cuts it out. It is a balancing act. When you are all done, resetting the ECU can upset the whole balance again as the converted voltage level(s) are obviously stored and resetting brings them to the default, incompatible with the physical positions you’ve set. Messing with it can cause you to spend a lot of time getting it back.
     
  15. Mar 28, 2008 at 8:01 PM
    #15
    Ridgerunner

    Ridgerunner [OP] Well-Known Member

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    Thanks Glassdoc, yeah it may be something I don't wanna get into that deep 'specially since I don't have the expertise. I've done more than my share of mods and repairs on all my old hotrods and such but this truck-even at 7 yrs old is way advanced. Maybe it would be easier to adjust the big screw in my HEAD!
     
  16. Mar 28, 2008 at 8:08 PM
    #16
    glassdoc

    glassdoc Well-Known Member

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    Well, it makes for good reading if nothing else to see if your truck has all the symptoms.. May be something else, IE: MAF, O2, Throttle needs cleaned, a lot of things have influence on the idle etc..
     
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