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Grounded throttle body and MPG

Discussion in 'Prius v Accessories and Modifications' started by Eric "v", Mar 6, 2015.

  1. Eric "v"

    Eric "v" Member

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    Recently I grounded my throttle body to the engine head per advice in a thread in the Modifications pages on getting better throttle response. Yeah, I know it's my own lookout when I make changes like this.

    I did get better, more linear throttle response but have since never got above 36.5 mpg. Previously I got between 38 and 39 MPG on the highway in varying terrain to and from Thousand Oaks, CA. It may be because I'm "unconsciously" using too much throttle or it may be a computer sensor (??) that has changed things.
    I do not know, but I may remove the ground wire just to see what happens next time I go from 'Vegas to LA.

    If there is a difference I may just hook up the ground wire for around town and disconnect and insulate one end for longer trips. I do like that better throttle response in traffic situations.

    Anyone else try this?
     
  2. Air_Boss

    Air_Boss Senior Member

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    Use a bigger wire... Seriously, why would you expect any difference at all?
     
  3. xliderider

    xliderider Senior Member

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    Try a smaller gauge (thicker) wire, and put a relay on it. You can then wire a switch in your dash to control the relay to engage/disengage the grounding of the throttle body.

    How about, use the Power Mode button? :ROFLMAO::confused::D
     
  4. Easy Rider 2

    Easy Rider 2 Senior Member

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    I sure am glad that you didn't see a post suggesting that you ground the positive battery post. :whistle:

    Seriously, that probably is making the engine run a bit richer, as evidenced by the better "response" and reduced mileage.

    Richer is not always better.

    It can cause carbon accumulation in the combustion chambers and have a bad affect on the cat. converter. It might take a LONG time for any serious negatives to show up.
     
  5. ChapmanF

    ChapmanF Senior Member

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    My first impulse was to look at the calendar but April 1 is still three weeks away, so I searched our beloved PriusChat to see just what kind of thread and advice that could be, and sure enough I'd missed a couple old threads talking about "grounding kits" apparently sold as a performance mod.
    I'm fighting the temptation to write much more about it as I need the time for other things, but thought at least it could be helpful to connect back to the older threads.

    -Chap
     
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  6. ftl

    ftl Explicator

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    Thanks for the links, Chap. The benefits promised after installing the wires from this site are quite amazing - even your sunroof will work better!

    http://www.sigmaauto.com/EGS/egs.php
     
  7. Eric "v"

    Eric "v" Member

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    Gents,
    Look at the "Rally Time/Attack Prius II" thread in this Mods page. There's a photo of the TB grounding. And yes, I used # 10 wire, thinking it was large enough.
    xliderrider's idea of using a switch is interesting. If I do it it will be right there on the ground wire.

    And yes, I do use the PWR button, probably too much. But with the TB grounding it is even better. And the standing start in ECO after the TB grounding is very good. So yeah, it may be running richer but I have no idea why it would with merely a ground wire. Maybe a sensor reading in the TB is changed with this mod.
     
  8. bisco

    bisco cookie crumbler

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    it is interesting. i thought you were kidding at first.
     
  9. ChapmanF

    ChapmanF Senior Member

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    Ah, this one.

    AFAIK, the two electrical things on the TB are the throttle position sensor and the ETCS motor, and wrxsubiemod must be of the opinion that neither one has an adequate ground wire brought to it in the harness connector. I'm kind of curious whether either item even has any continuity to speak of between its ground wiring terminal and its mounting to the TB. That ought to be a couple easy multimeter checks, but I haven't made them so I don't know.

    -Chap

    Once that switch is installed, I wonder if we could find any other PriusChatters in the Vegas area who'd volunteer for test drives to evaluate throttle response, while blinded as to the setting of the switch. :)

    -Chap
     
  10. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    Waitaminute......

    HUH?? :eek:

    I haven't pulled the TB on my 2010 yet, but I was thinking that it was made from.....
    Metal maybe?

    And it's bolted to an....Aluminum head and motor?

    My basic electronics training was quite a while ago, but wouldn't this mean that the TB is already GROUNDED?

    If I didn't think this was an elaborate early 01APR joke....I'd grab my Fluke and yank open the hood....
     
    #10 ETC(SS), Mar 7, 2015
    Last edited: Mar 7, 2015
  11. Eric "v"

    Eric "v" Member

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    ETC (SS),
    I do see what you mean. The plastic TB base MAY be where the TB bolts end up (ungrounded), or not. .... you may have a point... But I can say I've noticed a difference in throttle response. And it ain't my vivid imagination. (I use that when the last drink is called at the night club and I'm still looking at the "wimmen". Then my imagination and Dr. Beam come into play.)
     
    #11 Eric "v", Mar 7, 2015
    Last edited: Mar 11, 2015
  12. Easy Rider 2

    Easy Rider 2 Senior Member

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    Which is exactly why you should not be screwing with things you don't understand.
     
  13. ChapmanF

    ChapmanF Senior Member

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    I know that's the case in my Gen 1, but somewhere I picked up the idea that Gen 3 had moved to a plastic intake manifold on the 1.8 engine. So that part of the post maybe does make sense.

    AFAICT it may be the only part that makes sense; the electronic items on the TB have both power and ground in their wiring harness connections, and the one check that would shed a lot of light on this grounding idea would be whether either of those items even has continuity between its grounding terminal, and its mounting to the TB. That shouldn't be hard to check but I don't have a Gen 3.

    On the other hand, we do have the OP's self-report that the throttle response is changed, and that it's not his imagination. That's interesting as far as it goes, but of course there's a reason journals don't publish findings from self-reported perceptions. I'd still like to hear when that switch is in place and some other Vegas-area PriusChatters feel like doing some documented blind trials. :)

    -Chap
     
  14. rdgrimes

    rdgrimes Senior Member

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    A manifold may be plastic, but the bolts are not.
     
  15. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    I suppose we need is a picture or a description of exactly where the ground wire is placed.
    If the TB were to be made of plastic then I'm a bit of a skeptic on grounding it actually accomplishing anything.
    All of this is ridiculously easy to prove and it will cost anybody who is interested very littlle to investigate:
    [​IMG]
    I'd do it myself and document the results, but I'm convinced that this is all an early April fool's joke.
    Somebody read an article somewhere about K$N filters "improving throttle responses" and said to themselves: "Hey!...Let me start a rumor and see if I can get people to........." :)

    [​IMG]

    That's funny!

    Danny's "SPAM generator" came up with this after my last post. :D

    Don't try this at home......
     
  16. Easy Rider 2

    Easy Rider 2 Senior Member

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    +1 (y)
    Those are handy little meters, given the price but it should be noted that they will NOT indicate polarity.
    That is, there is no minus sign on the display and it will show just 12.6 no matter which way the leads are applied.
     
  17. Air_Boss

    Air_Boss Senior Member

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    Can't you get the same (or better) self-observed performance increase out of a couple of strategically applied decals?
     
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  18. rdgrimes

    rdgrimes Senior Member

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    Lets not forget the immense performance boost obtained from a set of chrome wheels.
     
  19. ftl

    ftl Explicator

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    Are these also called "go-faster stripes" in the USA?

    [​IMG]
     
  20. Mendel Leisk

    Mendel Leisk Senior Member

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    Hey, I've got one of those. Went out and checked:

    There's no continuity between throttle body and rest of car body. It's isolated.
     
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