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Old 01-04-2018, 07:49 AM   #1
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Throttle Position Reading at WOT

My 97 2.5 (throttle cabled) Boxster is have trouble in closed loop, Iím running out of things to replace and my Porsche shop is lost. They think the problem might be the TPS itís currently reading 80% open at wide open throttle. Is this normal?
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Old 01-04-2018, 07:56 AM   #2
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I don't see how, on my 2000 S it reads at 100% at WOT. If the computer thinks you only have 80% throttle maybe it is restricting fuel?

Since you actually have a throttle cable, is the sensor on the throttle body? Maybe it is only opening up 80%?

These are probably useless and obvious thoughts... But I figured I would add them

Good luck!
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Old 01-04-2018, 08:08 AM   #3
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I don't see how, on my 2000 S it reads at 100% at WOT. If the computer thinks you only have 80% throttle maybe it is restricting fuel?

Since you actually have a throttle cable, is the sensor on the throttle body? Maybe it is only opening up 80%?

These are probably useless and obvious thoughts... But I figured I would add them

Good luck!
Itís having trouble with the fuel map for sure. Thatís really all the shop knows (theyíre looking at fuel curves in real time) (MAF has been replaced twice during this process). The throttle is physically open 100% which weíve verified.
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Old 01-04-2018, 11:18 AM   #4
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Quote:
Originally Posted by truegearhead View Post
My 97 2.5 (throttle cabled) ... TPS itís currently reading 80% open at wide open throttle. Is this normal?
Is the throttle physically at WOT, or is it that the accelerator pedal is at WOT? If the pedal does not reach full open throttle, try the adjustment at the cable elbow. I read that it is actually fairly common. Someone posted a good write-up a year or two ago on one of the forums, but I can't find the exact one. This one should help:
Non e-gas throttle cable adjustment?? - Pelican Parts Technical BBS
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Old 01-04-2018, 11:25 AM   #5
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I've been searching for the post 78 mentioned and can't find it either. This is the best I can find. As an FYI my 98 shows 81% on the Durametric which is in the 79-82% range said to be normal in that thread. Pretty sure Loren was active in the other thread.

https://www.renntech.org/forums/topic/45038-throttle-cable-adjustment/

Last edited by 911monty; 01-04-2018 at 12:09 PM.
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Old 01-04-2018, 12:29 PM   #6
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Is the throttle physically at WOT, or is it that the accelerator pedal is at WOT? If the pedal does not reach full open throttle, try the adjustment at the cable elbow. I read that it is actually fairly common. Someone posted a good write-up a year or two ago on one of the forums, but I can't find the exact one. This one should help:
Non e-gas throttle cable adjustment?? - Pelican Parts Technical BBS
Iíve verified the throttle body is all the open and against the stop.
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Old 01-04-2018, 07:22 PM   #7
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I’ve verified the throttle body is all the open and against the stop.
If the mechanical parts are working properly, then you may have a failing TPS (throttle position sensor) that is telling the computer that the throttle is at 80% when in reality is at 100%..?

Last edited by Gilles; 01-04-2018 at 07:25 PM.
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Old 01-05-2018, 06:56 AM   #8
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nope 80% is what mine shows also. This appears to be the way its coded.
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Old 03-22-2018, 08:56 AM   #9
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My student this weekend had a 1997 Boxster and I put the RaceCapture in his car Sunday, and noticed that the TPS seemed to have a few spikes to 86 but also several flat plateaus of 80, and I'm pretty sure he was at WOT. May be a cable throttle Boxster thing?

Last edited by steved0x; 03-22-2018 at 08:56 AM. Reason: spinkes typo
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Old 03-22-2018, 09:16 AM   #10
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associated with this thread, yes?

Help needed with odd dyno results (2.5l time trial car)
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Old 03-22-2018, 10:44 AM   #11
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Originally Posted by steved0x View Post
My student this weekend had a 1997 Boxster and I put the RaceCapture in his car Sunday, and noticed that the TPS seemed to have a few spikes to 86 but also several flat plateaus of 80, and I'm pretty sure he was at WOT. May be a cable throttle Boxster thing?
80% is correct on the cable throttle cars
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Old 03-22-2018, 04:24 PM   #12
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i would suggest it's not the wot reading that is the issue, but possibly the readings it gives as it makes its way to wot - possible to log w a durametric?
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