ECMlink Adjust Your TPS!

Posted by GST with PSI, Feb 4, 2017

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  1. GST with PSI

    GST with PSI DSM Wiseman

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    San Diego, California
    A mechanically sound car is the cornerstone of any good tune. Things like boost leak tests, setting base timing, and base fuel pressure are just some of the commonplace things that are checked to ensure the car is ready for the road, and certainly before a performance tune. If one of these is out of wack, it can affect many other systems, as well as performance and driveability overall.

    The throttle position sensor (TPS) should be properly adjusted just like any other mechanical system on the vehicle. Although the ECMlink TPS Adjust feature will allow the user to scale an improperly calibrated TPS, it was never intended to serve this function. The TPS Adjust feature was intended to correct for sensors that are slightly out of position, or for an aftermarket/non-stock TPS. The TPS Adjust feature was NOT intended to alleviate the user from having to adjust it properly.

    Now, considering the statement above, the ECMLink TPS Adjust feature has become a pet peeve of mine. Nearly every log I look at, somebody is using it incorrectly. That being said, nothing is stopping you from using the feature incorrectly, just know, you're using it incorrectly. I strongly believe if you need to adjust the TPS offset or TPS scale more than a value of 2 on either scale, you need to go back and make a manual adjustment to your TPS. Say for example, you are at an 8 offset, on a 103% scale. That tells me the natural sweep of your TPS sensor is out of wack, and you need to go manually adjust it. On my personal cars, I'm happy when this feature is either disabled, or I'm at 0 and 100%...But that's just me.

    Additionally, I've seen TPS sensors that are scaled cause some wacky issues. I've helped tune a few cars that had idle issues that I believe were directly linked to the TPS being out of wack. In a few of these cases, the user was employing the TPS Adjust feature to compensate for an improperly adjusted sensor. After having the user simply adjust the TPS properly and disable the scalar (IPS settings remained functioning properly and unchanged), I was able to dial in idle and cruise without issue. Now, many of you may not have this issue, but I think it's definitely worth mentioning.

    Here's the bottom line: There's no substitute for a properly functioning/adjusted TPS. Fully closed, your TPS should read approximately 0.63v (RawThrotPos of 32) when logged in ECMlink. Open, it should read anywhere between 4.6v to 5v.

    Making manual adjustments to the sensor is as easy as loosening 2 bolts, tweaking the sensor until it reads the proper voltage, then tightening the the bolts back down. There's a good video outlining this procedure here:


    In summary, if you're asking for log advice and I'm bitching at you to fix your TPS, this is why.




    Other helpful links:
    http://www.ecmtuning.com/wiki/v3tpsadj

    https://www.ecmtuning.com/wiki/dsmlinktpsadjustment
     

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    Last edited: Feb 4, 2017
    My DSM:
    1992 Mitsubishi Galant VR-4

    Street Build

      manual
    1991 Mitsubishi Galant VR-4

    Street Build

    12.030 @ 119.39 MPH
    1990 Mitsubishi Eclipse GST (sold)

    16g   manual
    1991 Mitsubishi Galant VR-4 (sold)

    Street Build

    14b   manual
    1991 Mitsubishi Galant VR-4 (sold)

    16g   manual
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  2. Nate355RS

    Nate355RS Proven Member

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    Joined Oct 25, 2012
    Salem, Virginia
    +1 manually adjusting my TPS helped solve some of my idle issues. I'm seeing .63v with the throttle closed without correction.

    That said I'm very thankful for the TPSAdjust feature. Even if your TPS reads .63v at idle, it could still be just a hair off and oscillate between .63v-.65v when you cruise in gear with throttle closed. It's much easier to fix that problem by pushing a couple buttons then make tiny manual changes to the TPS.
     
    My DSM:
    1992 Mitsubishi Galant VR-4 (sold)

    Street Build

    16g   manual
    1992 Eagle Talon TSi AWD (sold)

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    1992 Mitsubishi Eclipse GSX

    Drag Race Build

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  3. Kryndon

    Kryndon Proven Member

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    Bulgaria, Europe
    Good read! The TPS position really is something which can be overlooked and yet result in big performance losses. Just for reference, here's a dyno run I did where it clearly shows how much the TPS impacts this. RED line is when the TPS sensor went entirely loose. BLUE is when I just bolted it back up without adjusting. And GREEN is when I tried adjusting it by the book. Although even now I still think it's improperly set.

    B11BpfV.jpg
    [​IMG]
     
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    Street Build

    14.769 @ 92.22 MPH
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  4. simplejoe

    simplejoe Proven Member

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    Ford City, Pennsylvania
    Great read! Should be a sticky
     
    My DSM:
    1999 Mitsubishi Eclipse GSX

    Street Build

    16g   manual
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  5. ishnish

    ishnish Proven Member

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    Modesto, California
    Got a bit of a dilemma here. I have adjusted, adjusted, and adjusted. Only to get my final outcome for my tps to where I still have to use the TPS adjust feature! My tps offset is set at 0 and on a 103% scale. Is this acceptable? With this, I am able to get 0.63v and a full 5.00v when I push the gas pedal in fully to where link will tell me I go from 0% throttle position to a full 100* (if scaled to 100%, tps volts is at .63v with throttle fully closed but only about 4.95v or so when gas pedal is fully depressed and throttle position only goes up to about 96%). Now, I have to also state, this is ONLY with the car off (as in not at idle). Once I start the car, I believe the tps volts is at 0.65v at idle and 5.00v with gas pedal fully depressed.

    Once again, is this acceptable? Or is it more acceptable to have, for example, car off (not started) with tps at 0.61v and car started with idle at 0.63v? Because I happen to have a difference of about 0.02v between car off and on.
     
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    1999 Mitsubishi Eclipse GSX

    Street Build

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  6. steve

    steve DSM Wiseman

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    St. Charles, Illinois
    On a 2G I'm still a firm believer in the factory adjustment if it's a stock TPS. I want the IPS switching at the correct point where the throttle opens. The voltage will be in the right ballpark unless the TPS is bad.
     
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  7. ishnish

    ishnish Proven Member

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    Modesto, California
    What do you mean by this Steve? Do you mean, as long as my IPS switches from 0 to 1 when throttle is closed to fully open?
     
    My DSM:
    1999 Mitsubishi Eclipse GSX

    Street Build

    16g   manual
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  8. steve

    steve DSM Wiseman

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    St. Charles, Illinois
    The factory 2G TSP adjustment procedure causes the internal IPS to switch at a specific throttle opening. The spec for the TPS voltage @ that point is subject to a wide tolerance and the ECU software accounts for that in it's scaling of the TPS percentage. I can't speak to what changes ECM Tuning made to the factory code but I've never seen a 1G or 2G that didn't work correctly with DSMLink when they were in correct factory adjustment for their model year.
     
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  9. ist dwa

    ist dwa Proven Member

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    Joined Nov 5, 2009
    Centerville, Ohio
    It is a fact you still must manually set the TPS to almost perfection. In some cases you can use the adjust tool to read right but when you actually go to press the gas pedal there could be a delay before the TPS itself sends out a voltage change. IE the throttle plate could be open 10% but the TPS thinks it is only open 7%, of course this causes all kinds of problems. The reason for this is because the TPS is technically supposed to be preloaded a tad, not preloading this creates a void and variance between electrical and mechanical percentages. I found this to be more of a problem with aftermarket throttle bodies but the concept works for OE as well if you just slap it on there.

    Set it manually as close as possible to .63V and then use the adjust tool if it is off only by +/- .03V, if it is off more than that reset it manually.
     
  10. jakelandry

    jakelandry Proven Member

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    Minden, Louisiana
    It bothers the piss out of me when people use settings to compensate for mechanical inconsistencies. Nearly every car I ever tune the owner has a fan or fuel pump on a switch, a tps out of place, or base timing off. They always have some excuse or reason for it which just bothers me that much more. The sad thing is this is a well documented subject that people are just too lazy to fix.
     
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  11. ishnish

    ishnish Proven Member

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    Modesto, California
    No excuses here, I am OCD and trying to get my TPS spot on. I have a 1g nt tb on my 2g gsx btw so I'm not sure if that has something to do with it. Steve Monroe himself worked on it and made sure everything was perfectly adjusted. The problem arose when I installed my new catch can setup, I had a vacuum line loose and didn't realize it. All I had to do was book it back on to the intake mani but because I didn't realize it, a buddy of mine told me to screw in the BISS. I turned it maybe 1/8 of a turn if that before realizing it was the hose.

    Ever since then, I've had trouble with this dang TPS!
     
    My DSM:
    1999 Mitsubishi Eclipse GSX

    Street Build

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  12. Mauispyder

    Mauispyder Supporting Member

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    Kula, Hawaii
    Any tips for accessing those two TPS screws? IIRC I had to use pliers and a screw bit to get to the thing. Any special tools to make it easier? 2g here.
     
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  13. doubleclutch

    doubleclutch Supporting Member

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    Canton, Michigan
    I had luck with a screw bit and a 1/4" socket driver.
     
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    1998 Mitsubishi Eclipse GSX

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  14. 1990TSIAWDTALON

    1990TSIAWDTALON Moderator

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    Replace them with allen head screws, much easier to work with. My local Fastenal had them, Lowes etc probably does too.
    You'll thank yourself time and time again.
     
    My DSM:
    1992 Eagle Talon TSi AWD

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  15. NBMitz

    NBMitz Probationary Member

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    A trick that worked perfect for me was to grind an 8mm socket and make it a low profile 8 mm. It fits nicely on the lower bolt... here’s a link... Jafromobile knows what he’s talking about!
     
    My DSM:
    1995 Mitsubishi Eclipse GST

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  16. NBMitz

    NBMitz Probationary Member

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    thats a great idea!! Thxdsmr’
     
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  17. Buddy2

    Buddy2 Probationary Member

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    Helsinki, Europe
    I wonder why mitsubishi has not made adjusting screw for how open plate can go. Its easy to get it 0.63 but getting wot to 5 seems to need some bending of that metal plate for me. Unless im missing something.
     
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  18. steve

    steve DSM Wiseman

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    St. Charles, Illinois
    Why are people hung up on the WOT TPS voltage? I don't get it.

    Does your butterfly open to 100%? If it does and your idle switch is doing what it should, when it should, the WOT voltage doesn't have to be 5v.
     
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