Results 1 to 2 of 2

Thread: TPS Problem

  1. #1
    Current UZA80 owner Chief Engine Builder JustCallMeOrlando's Avatar
    Join Date
    Aug 2005
    Location
    Western Australia
    Posts
    4,152

    Default TPS Problem

    Hey all,

    Just curious if anyone could shed some light on a problem i'm having. I can't remember this happening with my Gen2 setup, if it did it was a minor problem compared to its other issues

    I find sometimes when I get back on the throttle after being off it, there is this pause where it does nothing, then all of a sudden I get this jolt when it does come back, not the smoothest thing in the world. It doesn't matter if you give it more throttle, nothing happens. If you do, it tends to give you an even bigger jolt when it does come back. I dont tend to find it happens when i'm giving it shit, only when i'm puttering around, then again, 90% of my driving isn't like that.

    It's happened with both my Gen3 ECU's so i'm pretty certain it's external to them.

    I'm pretty sure I checked that the TPS steps off the IDL position as soon as you crack the throttle.

    I've once got an error code to say that TPS was in IDL and ACC at the same time, but i've not seen it since.

    Does this still sound like a TPS calibration problem, or a borked TPS?

    Cheers,
    Nathan
    Teh UZA80 - Project Century - Remotely p00'd by association

  2. #2
    Junior Member Too Much Toyota oldcorollas's Avatar
    Join Date
    Aug 2005
    Location
    sydney
    Posts
    12,496

    Default Re: TPS Problem

    it sounds exactly like the mixture is a bit on the "lean side of drivability" in the off throttle table..

    i could replicate this easily with the Megasquirt when playing around... i found that after trailing throttle, if mixture was too lean, or should i say, not rich enough, then it would buck when throttle was touched... if i added in accel squirt, or decreased TPS threshold before it kicked in, i could get it to go away somewhat, but not everywhere. i found best compromise was to make trailing throttle a little richer (but not actually very richer.. just.. richer) so then it would not hesistate when a little more air came in. it was definitely nowhere near the point where it would start cackling from being too rich on decel.... that was maybe anopther 30-50% fuel i am only talking about 2-5% fuel difference (which on the grand scheme of injector ability was maybe 1-2% duty maximum change i made)

    i doubt it is TPS, as the amount of throttle input should not be enough to engage the accel squirt.... so it is a purely table based issue, which is why it happens with both ECU's but of course i could be very wrong

    so yeah, i would suggest it is less TPS, and more to do with the mapping in that part of the table (ie lower kPa than cruise since it is trailing throttle)..

    you could also move TPS around see if it changes it, or measure resistance with rotation.. if it is a smooth change, no jumps, then it is probably ok.
    "I'm a Teaspoon, not a mechanic"
    "There is hardly anything in the world that a man can not make a little worse and sell a little cheaper" - John Ruskin (1819 - 1900)

    AU$TRALIA... come and stay and PAY and PAY!!! The moral high horse of the world!

Similar Threads

  1. TPS Idle Switch
    By JetspeedCamry in forum Tech and Conversions
    Replies: 21
    Last Post: 19-03-2006, 05:44 PM
  2. 20v TPS? & MAP?
    By Jonny Rochester in forum Tech and Conversions
    Replies: 9
    Last Post: 07-03-2006, 07:19 AM
  3. Full-variable output TPS - what cars ??
    By ed in forum Tech and Conversions
    Replies: 5
    Last Post: 20-02-2006, 11:59 AM
  4. Gen2 3SGE Idling problem - Take 2
    By alliance_22 in forum Tech and Conversions
    Replies: 22
    Last Post: 21-12-2005, 06:54 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •