Throttle Position Sensor [Suspected Faulty]

[Hags86]

Car occasionally wont rev, just idles and coasts.

I have some logged data that points to it being a faulty throttle position sensor. Do these things fail in practice? Just get the feeling I'm about to start on a wild goose chase.

[Ultramaroon]

Looks like the only stock part you have is your gas pedal. You might get more help if you move this thread to the swaps section. I doubt the fault lies with the only part that hasn't been touched.

[Hags86]

Originally Posted by Ultramaroon

Looks like the only stock part you have is your gas pedal.

I doubt the fault lies with the only part that hasn't been touched.

My thoughts too. The Motec logging is pretty specific that it's a failed TPS or wiring but that's OEM so probably OK.

[Hags86]

So I spoke to MoTec to see if it might be a hardware fault of the ECU (reading the wrong voltage on the sensor).

Turns out a failed accelerator pedal is a known fault and they've replaced lots of them on the Toyota 86 Race Series cars. It looks like high lateral load on the pedal from heel-n-toe on downshifts splits a plastic bushing internal to the TPS and one side fails. There are two TPS sensors built in (for safety) and when there is a difference in voltage between the two the ECU stops acceleration.

I'll post this in the tracking section where the heel-n-toe action lives.

[steve99]

Originally Posted by Hags86

So I spoke to MoTec to see if it might be a hardware fault of the ECU (reading the wrong voltage on the sensor).

Turns out a failed accelerator pedal is a known fault and they've replaced lots of them on the Toyota 86 Race Series cars. It looks like high lateral load on the pedal from heel-n-toe on downshifts splits a plastic bushing internal to the TPS and one side fails. There are two TPS sensors built in (for safety) and when there is a difference in voltage between the two the ECU stops acceleration.

I'll post this in the tracking section where the heel-n-toe action lives.

Thanks.




can you activate auto-blip on downshift (rev match) on motec ? , but I gather is locked on 86 series cars

[Ultramaroon]

Originally Posted by Hags86

So I spoke to MoTec to see if it might be a hardware fault of the ECU (reading the wrong voltage on the sensor).

Turns out a failed accelerator pedal is a known fault and they've replaced lots of them on the Toyota 86 Race Series cars. It looks like high lateral load on the pedal from heel-n-toe on downshifts splits a plastic bushing internal to the TPS and one side fails. There are two TPS sensors built in (for safety) and when there is a difference in voltage between the two the ECU stops acceleration.

I'll post this in the tracking section where the heel-n-toe action lives.

Wow! I noticed a few months ago that mine felt a little wobbly. Now I'll have to look at that! Thanks for the heads-up.

[ermax]

Originally Posted by Ultramaroon

Wow! I noticed a few months ago that mine felt a little wobbly. Now I'll have to look at that! Thanks for the heads-up.

Mine too. Sometimes at full throttle I will feel it shift sideways a tad and go down a little farther. Been meaning to look down there because it’s kind of annoying. I always heal toe so maybe the side loading has gotten to mine.

[Ultramaroon]

Originally Posted by ermax

Mine too. Sometimes at full throttle I will feel it shift sideways a tad and go down a little farther. Been meaning to look down there because it’s kind of annoying. I always heal toe so maybe the side loading has gotten to mine.

I do too. I smell a mod in our future. :/

[Ultramaroon]

Checked mine yesterday. Nothing's wrong except for it being plastic. Can't do much for that.

[Hags86]

So, I installed a new accelerator pedal and the problem remains.

The logs show the Main position voltage OK but the Tracking (safety) one drifting up. I've repinned this to a spare analogue voltage input on the ECU. That will tell me whether it is a wiring problem or a fault on the analogue to digital converter on the ECU.

[FR_STEEZ]

Originally Posted by Hags86

So, I installed a new accelerator pedal and the problem remains.

The logs show the Main position voltage OK but the Tracking (safety) one drifting up. I've repinned this to a spare analogue voltage input on the ECU. That will tell me whether it is a wiring problem or a fault on the analogue to digital converter on the ECU.

Ever fix the issue. My pedal has a dead space the first few degrees in the pedal and it does wobble a lot cause I always heel toe.

[TRD83]

I’m receiving the same fault (P2135) and symptoms ( can’t rev over 2500 rpm) but it will only happen once every 2,000 miles or so.

I’ll restart the car once or twice and the error goes away.

I transferred engine and ECU (not gas pedal) to a different car and the problem followed. Still only happens once every 2,000 or so miles and I’ll clear code and restart the car and it’s fine.

Goose chase continues

2013 FRS, edlebrock supercharger, delicious tune, delicious E85 sensor/ dbox.