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Thread: Help please I give up TPS problem.

  1. Default

    I post my issue on prime too and this where i am now to keep you up to date:

    if i try to explain my issue more clearly:


    - when the TPS is plug in: i can feel like a very very light stop and go thing when i accelerate moderatly (not when i am steady at speed). i am the only one to feel it in the car, if i do not tell it to my wife she do not bother. i fell kind a lack of power but i think it is only due to the intermitent throttle or at least it is what i think. at WOT i have no problem

    -when i unplug it i have the feeling the car just runs great, more torque, i cannot tell anything else (but i did not try WOT, i don't know how trigering the CEL can arm the engine in WOT condition)

    injector are standard as ECU
    injector not cleaned (but i will do it one day)
    fuel filter changed (and i already bypass the fuel regulator with no effect at all, but did not go forward checking fuel delivery precisely)
    valve clearance done with timing belt 3 years ago can't say if it as been done the right way but i think so
    i have to check for leaks but i really don't think it is my problem as it was already there before i changed all the exhaust thing (and i changed everything just beacause of my issue...)

    i can tell that when i first plug back the new tps i did not adjust it to test. and it trigger the TCS. when i adjusted it correctly the TCS went away. so i think it cannot be reverse polarity.

    - test TPS AT THE ECU, got VCC 5V , min 0,53 max 4,37V, very linear all across no peak at all (i have a video to confirm)
    - Test second TPS (under the trottle body, for TCS use i think), VCC 5V, min and max ok (more close to the 0,5v 4,80v than theTPS i changed though) and linear too
    - if i disconnect TPS: Engine CEL and TCS light up but car runs good just high idle (1200 rpm)
    - if i disconnect the second TPS and the top TPS stay connected: engine CEL+ TCS light car get the issue

    We can maybe consider that there cannot be conflict between the two as it would have runs good with the second one disconnected.
    we can consider that The ENG CEL do not triger a limp mode solving the issue every time. is there multiple limp mode????

    - if I disconnect an O2 sensor and both TPS stay connected: engine CEL car get the issue

    I tried to see if another type of engine CEL/limp mode will act like the one i get from disconnecting the TPS but No.... big disappointment there

    - if everything is connected properly: Very good idle 800 rpm steady and all no cell but same issue as before

    - drove the car traction control Turned off TPS pluged in and the issue was still there.

    I will work again on the car tomorrow.
    when i unplug the O2 sensor the car runs as bad as before. we can conclude that unplugging the O2 sensor do not trigger the same fail safe mode as unplugging the TPS. and i think if unpluging the TPS was acting on close or open loop, unplugging O2 sensor would do it too.
    i will test the O2 for rich VS lean condition as you told me
    i read elsewhere on prime that the car has 5 different map for different issue but really do not know much else.

    so what that TPS limp mode can change to blur my issue like this

    if you have any other ideas on what i can troubleshoot tell me, i ll have some time for it tomorrow.

    thank you sooooo much for helping me on this

  2. #12
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    Default

    If I understand correctly you only have hesitation while going from throttle position 20% to 30% (for example). While you hold the throttel constantly at 20% or 30%, the cars runs smoothly, no hesitation, right? If so it sounds like a bad communication between the ECU and the TPS. Just wondering, is the ECU modified or stock?

    I've found this here: http://www.nsxprime.com/forum/showth...lacement-howto
    Not sure what you mean by the modification that is needed to make it work.

    Also, there are two versions out there, one for 95-00 and one for 01-05 AFAIS. Which one did you use?

    Not a serious proposal: let your wife drive the car, problem solved.

  3. Default

    the ecu is stock as far as i can tell, the car was totally stock when i bought it. i think nobody would modify the ecu without modifying anything else on the car.
    the only tps i found wad the 95/00 and my car is a 93.
    when the TPS arrived it was turning the wrong way (as i already read on several prime post), all i done was swapping the spring inside with the one on my original TPS to make it turn the good way. the parts is exactly the same apart from that. i was planning to reverse the plug too but it appears that the voltage was going the right way from start .

    and my wife already drive the car!!!! sadly i drive it too some times

  4. #14
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    Default

    Did the modification work for the guys on prime?

  5. #15

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    As you've already replaced almost everything except ECU why not remove the fuel tank and replace the old and weak fuel pump.
    Pride.

    1992 My beloved Red/Black manual NA1.😎
    1992 Chevy Lumina apv Rockford Fosgate sound system demo van.🙉
    2003 Hartge Mini Cooper S (2 x UK & 1 x European sound quality finals winner) 🏆 

    "The NSX's greatest victory was to WIN the 1995 Le Mans 24hr GT2 Class"
    ..............and guess what, it was a RED one but of course.  

  6. Default

    Quote Originally Posted by goldnsx View Post
    Did the modification work for the guys on prime?
    on prime i only found the information that the 95/00 one turn the wrong way. the guy has not modified it

  7. Default

    exactly because i already replaced so much thing for nothing (and in fact sometimes for worst).
    i know the pump will have to be change at one point, but i do not think it is the culprit because bypassing the resistor did not change anything and i do not see why tps unplug the car would run good with a bad fuel pump
    but an easy way would be too check fuel pressure and i am planning to do so

  8. #18

    Default

    My 92 has developed similar symptoms when away in Spa last weekend (strangely enough when giving it some beans on the 3 parade laps) and the consensus of opinion around a lunch table general chat was to replace the fuel pump as apparently they are known to get weak over time and in your case 25 years now.
    Pride.

    1992 My beloved Red/Black manual NA1.😎
    1992 Chevy Lumina apv Rockford Fosgate sound system demo van.🙉
    2003 Hartge Mini Cooper S (2 x UK & 1 x European sound quality finals winner) 🏆 

    "The NSX's greatest victory was to WIN the 1995 Le Mans 24hr GT2 Class"
    ..............and guess what, it was a RED one but of course.  

  9. #19
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    Dec 2007
    Location
    Switzerland
    Posts
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    Default

    Not sure if it's a weak fuel pump. Could be but I'd monitor the fuel pressure before taking out the fuel tank. Fuel pressure gauge and small camera while accelerating.

    FPR ever changed?

  10. Default

    Quote Originally Posted by goldnsx View Post
    Not sure if it's a weak fuel pump. Could be but I'd monitor the fuel pressure before taking out the fuel tank. Fuel pressure gauge and small camera while accelerating.

    FPR ever changed?
    FRP= fuel pressure regulator?
    no i don't think so

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