Pedal sensor (accelerator)

[Mercurios2011]

My HUD only reads 84% (TPS) at full throttle , it can go from any % to max 84% pretty quick , but I have never been able to hit 100% even with this new pedal sensor that I installed few hours ago.
I can only assume few things,
1. Even with the reflash the stock MAF won't allow it , and I have yet to find a HPerfomace MAF
2 The pedal itself has a built in restrictive range ,is like it has a built in stop at the bottom preventing from going futher down
3 The HUD can't read it simply because it can't keepup since it reads from the OBD2 and not directly from either the ETB or the APS


Has anyone here had a similar issue?
Thanks in Advance

 

[scotman]

The accelerator pedal failure is not common. It’s not a high voltage sensor. So, it isn’t an item that gets very warm as a consequence of doing it’s job. I’ve seen a couple of them that the failure exhibited itself by having one or more dead spots in its operating range of motion. It’s just one of those things that occasionally happens.

 

[SyntheticAtmosphere]

Many (possibly most) drive by wire cars dont achieve 100% throttle plate angle even when the driver full applies the throttle.

 

[Handy Andy]

The pedal (Accelerator Pedal Position Sensor - APP) uses two separate outputs from two types of power supply. One for the PCM, which is that Pulse Width and the other is a simple resistive range.

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You Gotta' be careful, because one power supply feed is directly fused to the "Hot in Start or Run" section of the Engines' Fuse Box to power the side of the pedal that uses Pulse Width (a method of averaging is done back at the PCM) modulation signal (that whine you can hear from the engine when it's off - as the throttle body "seeks" that setting) as you modulate the pedal.

A second power supply is the HS CAM - so that is low voltage 5V logic stuff and is a simple Resistive result send to the Instrument cluster - that power is supplied thru the Body Control Module.

So in reality WOT is all that the system needs to attain, so that can get set from 70% to all the way up 100% - but the results you see on the HUD is what it thinks it is - then that is dependent on the results the Pods see from one side of the sensor, not necessarily what the PCM is setting the throttle to - that feedback is pre-set for the PCM to worry about.

Best way to check is to remove the snorkel and have someone move the pedal to various positions and call out so you can shine a light into the throttle body bore and observe the plate and it's position.

 

[Mercurios2011]

the pedal won't allow any ajustment, 2 Bolts with no wiggle room 🤷‍♂️ , i did press and depress very slowly with key in acc mode to reset the new unit to the also new ETB, the car runs fine , just seems kinda odd on the reading , so I was wondering if yall had similar issue

 

[Mercurios2011]

The accelerator pedal failure is not common. It’s not a high voltage sensor. So, it isn’t an item that gets very warm as a consequence of doing it’s job. I’ve seen a couple of them that the failure exhibited itself by having one or more dead spots in its operating range of motion. It’s just one of those things that occasionally happens.

It just quit working and left me on foot , luckily I was at dads , and course I replaced with the same unit that came originally equipped wich is HeLLa

 

[scotman]

That procedure you had to do is called “slope determination”.

 

[Mercurios2011]

Ahh I see, I found it on a video from a UK owner
While I did read in a different page altogether saying to press and depress 5 times in a 15 / 30 secs time frame that didn't work the 1st time, so I after I installed the new ETB did it the simple way and the car crank and inmediatly idle itself quietly, didn't even had to wait for the ETB to calibrate itself like I had to the very first time it was replaced, now I can resume the Bolt ons chasing that massive whooping 2.5/5 hp gains 😂🤞

 

[PapaJim13]

The pedal (Accelerator Pedal Position Sensor - APP) uses two separate outputs from two types of power supply. One for the PCM, which is that Pulse Width and the other is a simple resistive range.

View attachment 8106​

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I'm wondering about something here. What would be the best method to have 2 engines run off of one throttle pedal? Obv I cannot just splice the throttle body wires together. If I just splice wires 5 and 6 on the accelerator pedal as those communicate directly with the PCM do you think it would work? I don't know much about vehicle electronics but if the PCM sends voltage through those yellow and green wires, I feel like the other PCM connected to the same wires would get confused as hell as to what is going on. If the accelerator pedal's inputs were constant voltage I'd assume the PCM's would be fine with it as they'd have no way of knowing they're spliced together.

Would it be better to modify my current accelerator pedal to mechanically connect the second and just keep the wires completely separate?

 

[Handy Andy]

Hmmm...Running two motors off of one pedal - a bit different than a simpler change of gearbox ratios by offering a different axle with a pinion gear that has more teeth and it's ring gear with same if not - fewer teeth to make their ratio closer- now if you were a truck driver you'd just have to flip a lever to move the pneumatic to shift a rod to push the ring gear on another 2nd axle onto the driveshaft at the same time pulling the other ring gear off so the new ring gear and it's ratio takes over the gearbox output.

IT's when you switch PCM - but is it necessary? Well, the only thing I see "different" - if you want to keep the same pedal yet operate a different motor - is to let the other motor "see" the pedal - the problem lies in zeroing out the starting of the other motor and using that pedal to control it.

So to answer your main ending question, you'd need to isolate the other motor from the one you are using. Then to switch - the linkage then can take over on the other throttle body. You'd need a relay or isolation of some kind so the motor waiting to come on-line won't stall trying to follow - until you switch that over to it. So it'd need a "idle" signal just to stay running until it's needed then the Relay also swaps the PCM throttle to pedal connection to take over the RPM on the other motor.

Or do we need another throttle body? (Thinking a diverter valve) like what turbos use, only you are taking and letting the other motor "idle" and then when you switch to the other motor - the vanes then let the air from the one throttle body flow into the other manifold - then does the other PCM - that other motors PCM; need to see the newer lines from the Pedal as well as take over the function of rising to the RPM the other motor was revving at

Not sure where to take this. I hope I'm following you - what is your plan or are you still taking concepts?

 

[Mercurios2011]

this is way outside my knowledge

 

[Handy Andy]

IN the process of switching engines the issue of "zero accelerator = Idle speed" can be mimicked by using a preset series of values to fool the 2nd PCM as to the 2nd engine remains at idle until that moment when the switchover can occur where the valve shifts manifolds, and the relay (or switching device) drops out and the new values on the 2nd PCM are presented thru the wiring from the throttle and the switchover as the 2nd PCM sees the new input from the accelerator - it's the process of making it as transparent as possible - for the 2nd engine would have to see a sudden rise in throttle position input while the 1st engine uses the values from the switched as "Zero accelerator = Idle Speed" and the manifold swapping has to be as efficient and quick as possible.

At least in my thoughts - it's the only way to make this process work - but the issue of shifting the 1st engines transmission over from engaged gear to neutral and the new transmission (2nd motor) then takes over this process.