0% TPedal = 3% TPlate but 2% TPedal = 2% TPlate

FlashPro questions & answers specific to the 2006-2009 (US, UK, Asia) S2000
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shind3
Posts: 113
Joined: Mon Jun 30, 2014 8:02 am
Location: Pittsburgh, PA

0% TPedal = 3% TPlate but 2% TPedal = 2% TPlate

Post by shind3 »

I think there is a problem with the synchronization of the mechanical rest position (dictated by vertical set-screw) vs ECU commanded minimum position of my throttle body. The mechanical rest position TPlate% is higher than the minimum TPlate % as commanded by the ECU. This causes the TPlate% to actually decrease as you increase TPedal%! See following image or attached datalog.

Image

In decel mode, the ECU seems to turn off "closed-loop feedback controlled" actuation of the throttle body which results in the TPlate% defaulting to the mechanical rest position. But, as soon as you apply even the tiniest bit of TPedal%, the ECU moves this to a position that is lower than the mechanical rest position (overriding the spring).

See the following video of this phenomenon captured during IGN on/Engine off mode.
https://www.youtube.com/watch?v=0PrVLWUn_CM
When you hear the high pitched noise, that is when I manually increase the TPedal% by a very very slight amount that is just enough to activate the ECU's manipulation of the TPlate%. As you can see, the mechanical rest position (no high pitched noise) has a larger TPlate% than a TPedal% of just slightly larger than 0.

I tried to manually adjust the set screw by loosening it about 3 turns which results in the following mechanical rest position but now the ECU throws a code for P1683 - Throttle Valve Default Position Spring Performance Problem.


So, I tightened the screw by 1/2 a turn and now no CEL is thrown but upon visual inspection, you can tell that the TPlate% reduces very slightly as TPedal% is increased from 0% to 2%. The attached datalog and picture mentioned above is from the throttle body adjusted as such.


I hope the reason I don't want the throttle plate to close when I press on the pedal is obvious to everyone reading this.


So, what can I do to make sure the TPlate% during ECU control in 'decel mode' is equal to or higher than the mechanical rest position?
This is not a problem when not in decel mode (overrun mode) as the ECU does not relinquish control of the throttle body.

Can someone take a video comparable to the above mentioned videos? Same with the attached datalog?

Can the following table please be exposed for the S2000?
Minimum throttle opening compensation

This table adjusts the throttle opening upon overrun by coolant temperature

throttle-open-comp

Settings all values to -100% will disable the overrun throttle opening.
Is there some calibration procedure I can do? I've tried to pull the ECU fuse, let it warm up to above 196F and idle for 5mins. This produced no observable change.

Thanks
Attachments
Shek 70mm TP, 24.fpcal
only mod is a 70mm TP
(8.88 KiB) Downloaded 198 times
Shek 70mm TP, 24-141003-173643.fpdl
check Tplate % around the 0.600s mark
(1.76 KiB) Downloaded 192 times
Last edited by shind3 on Sun Oct 12, 2014 2:21 pm, edited 1 time in total.

shind3
Posts: 113
Joined: Mon Jun 30, 2014 8:02 am
Location: Pittsburgh, PA

Re: 0% TPedal = 3% TPlate but 2% TPedal = 2% TPlate

Post by shind3 »

Don't everyone post all at once now... lol

shind3
Posts: 113
Joined: Mon Jun 30, 2014 8:02 am
Location: Pittsburgh, PA

Re: 0% TPedal = 3% TPlate but 2% TPedal = 2% TPlate

Post by shind3 »

Whoops, just realized that you guys weren't able to see the video. Reuploaded. Please view it now.
https://www.youtube.com/watch?v=0PrVLWUn_CM

Thanks.

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