Erratic TPS signal - Fix suggestions?

[White95]

I'm experiencing an issue with my TPS signal, which is basically oscillating, causing it to jump in/out of Closed Loop. Worth noting that this issue only happens with throttle input, so not when coasting or at idle. My setup is a 2017 Coyote in a '95 Mustang. I'm using HP EFI V6, the TiVCT controller, my battery is in the trunk, and I have a PWM fan controller. My throttle body is a FAST 54087 and it uses LS style TPS & IAC. My battery is grounded to the engine block, and the engine block is grounded to the RH frame rail. The main lower lead goes to the starter, and from there to the main fuse box. The ECU power and ground are both connected to the battery. There are no other electronics aside from this. I'll attach a recent datalog file and a copy of my Global File for review.

Aside from this list, anyone have any ideas? We've reached a wall and cannot further tune the car until this is sorted.

Steps taken and results:
New TPS sensor - Replaced the O'Reilly brand TPS sensor with an ACDelco part. Had no effect.

New throttle cable - Swapped the Lokar cable, which was only supposed to be temporary to begin with, for a Motion Raceworks cable. Smoother throttle response, but no effect on single issue.

Knock sensor deactivation - The wiring from my TPS & IAC runs in the intake valley in close proximity to the sensors. Had no effect with them disabled and we've since reactivated them.

Secondary throttle return spring - My car has a very stiff suspension and it was suggested to try this to steady the throttle blade. Had no effect.

RFI noise filter - Checked and found that only one has been installed. Results pending.



Files saved to Zip folder attached.

[andrewb70]

The issue is clearly visible in the datalog, but you have already tried the obvious things to fix it. The TPS is definitely jumpy and it's not only keeping the ECU from going into Closed Loop, but it also keeps adding Acceleration Enrichment based on the false TPS fluctuation. Please keep us posted as to what you find. Andrew

[George F]

Do you have an unused Input available? This will need to be configured as a type (5) Input. You can try temporarily splicing the 5 volt reference wire that goes to your TPS into this (5) Input. Monitor this input and view a datalog of this occurrence, and make sure the 5 volt reference to the TPS is actually a consistent 5 volts. I’m not suggesting that this is necessarily the culprit, but it'll help rule that out.

[Danny Cabral]

Maybe try a Ford Motorcraft TPS?

[White95]

I do happen to have a new Fox Mustang style TPS leftover from my pushrod engine days. I could try, if it’ll fit my throttle body.

[White95]

Decide to see how it acted with the engine off and here's what I found: https://youtu.be/bSwwuCo7BB8

Transcript: With the engine off, I added throttle in small increments then kept it steady. The TPS signal would spike and the fall. Did this each time I added any input.

[Danny Cabral]

TPS Autoset error indication updates: More thorough descriptions and indicates voltage values.

The latest V6 EFI software supposedly can display TPS voltage values, but I'm not sure if that's only for TPS Autoset error occurrences (?): https://documents.holley.com/techlib...10-11-2021.pdf (Holley EFI V6 Revision Log)

[White95]

The Delphi sensor produces a much cleaner TPS trace out of the box. I'll report back with a drive datalog.