Car revs to 4K and holds RPM -FBM

[Kerber23]

Originally Posted by wparsons

Get out a voltmeter and actually measure the voltage at the TPS (on the throttle body). If the code is saying it's below the minimum voltage, and gives you the expected minimum voltage, that's a very good place to start.


If you're going to go with the logging route, log both the throttle position and pedal position and give the throttle some obvious inputs, look for it to be logged and see what the TPS is showing at the same time.

Thanks for your continued help. I borrowed a meter to use but I've never actually used one. I found the wiring diagram (http://www.ft86club.com/files/BRZwiringi.pdf) how do I test this? If I just displayed gross incompetence and you think I should leave it to a mechanic say so, I won't be offended lol.

[EAGLE5]

Originally Posted by wparsons

TPS (throttle position sensor) is in the throttle body, even on drive by cable cars. The pedal sensor tells the ECU how much throttle you want, the TPS tells the ECU how open the TB actually is.

Argh! My bad. I meant pedal position.

[Kerber23]

Originally Posted by jsimon7777

Argh! My bad. I meant pedal position.

Haha its fine. Ill go take a look!

[Kerber23]

Originally Posted by jsimon7777

Argh! My bad. I meant pedal position.

https://gyazo.com/c74d62a87990904eb87bdada0c74d74c

Edit: sorry saw the other post

is this what you were looking for in the log?

Pink is Accelerator angle
Blue is throttle angle

I most certainly floored the accelerator and tapped it several times when the Accelerator angle read 0 but the throttle angle plateued.

[wparsons]

Hold up, you floored it in that log? The max pedal angle I see is like 35%.

[Kerber23]

Originally Posted by wparsons

Hold up, you floored it in that log? The max pedal angle I see is like 35%.

I floored it when the Throttle Angle was more elevated dispite accelerator angle showing 0. I floored it. Tapped it. And it showed 0 change in throttle angle

[wparsons]

Can you get a log with the car not running and just sweep the throttle pedal angle from 0 to WOT and back slowly? I don't know if it'll move the TB with the car off not running, but it'll be interesting to see what the pedal is logging.

[why?]

Part of the issue you are having is the subaru limp mode. It maxes rpm's at 4k when any lights go on. My guess is that is why it only goes to 4k, and not revs the engine until it explodes.

There's always a chance the tuner broke the map in some way the car wasn't expecting with the throttle position.

[wparsons]

Originally Posted by why?

Part of the issue you are having is the subaru limp mode. It maxes rpm's at 4k when any lights go on. My guess is that is why it only goes to 4k, and not revs the engine until it explodes.

There's always a chance the tuner broke the map in some way the car wasn't expecting with the throttle position.

Unless I misread it, he said it hangs at 4k rpm even without throttle input. Limp mode would stop it from revving higher, but shouldn't hold it there without touching the gas.

[why?]

Originally Posted by wparsons

Unless I misread it, he said it hangs at 4k rpm even without throttle input. Limp mode would stop it from revving higher, but shouldn't hold it there without touching the gas.

Unless the sensor was broken. I had a car do this to me decades ago, there was a piece that stopped the throttle from going farther down and it broke. When I didn't press the pedal the car always revved to 2000 rpm. I assume subaru doesn't use that piece for drive by wire, but I can easily see if the sensor is broken ( or the map values are messed up) it decides it should rev at 2k rpm's.

[Kerber23]

Originally Posted by why?

Unless the sensor was broken. I had a car do this to me decades ago, there was a piece that stopped the throttle from going farther down and it broke. When I didn't press the pedal the car always revved to 2000 rpm. I assume subaru doesn't use that piece for drive by wire, but I can easily see if the sensor is broken ( or the map values are messed up) it decides it should rev at 2k rpm's.

Would it also ignore all throttle input when that happens? I'm asking the local group if I can borrow someone's gas pedal since it seems its all one unit.

[Kodename47]

Originally Posted by wparsons

Can you get a log with the car not running and just sweep the throttle pedal angle from 0 to WOT and back slowly? I don't know if it'll move the TB with the car off not running, but it'll be interesting to see what the pedal is logging.

Tried this? The throttle will move with the pedal if all is well and is logable.

[Kerber23]

Originally Posted by Kodename47

Tried this? The throttle will move with the pedal if all is well and is logable.

I was able to log the both with the car in the accessory position. The accel went from o-100 and I heard the throttle body opening as wel.

[Kiske]

As stupid as it seems wipe the codes and battery reset the ecu. That should fix your 4k issue. And likly what your seeing with the tps. I'd start with the map. Sadly, when I had issues with mine, LJ could only sell me another one to see if that fixed the issue. Fbm map sensors are just restickered omni 3/4 bar sensors should you noy want to spend 90$.