Throttle Position Issue

[cameron]

Hi All,
Have an issue with a contact less hall effect TPS sensor on a cable throttle carburetor Formula Ford. Image of setup as attached. Issue is that the throttle position will read a negative % valve when off throttle (as pictured) and gives an inaccurate throttle pickup trace, Any suggestions on how to fix this.
Dash Is a Motec Sports dash
2008 Mygale Formula Ford
Data from qualifying at Pukekohe New Zealand

[David Ferguson]

The spikes in your data look like a wiring issue. that is what intermittent connections look like. It could also be interference with something like a radio transmission.

Check other sensors using 5V, to see if it could be the 5V power that is being shorted. If so, they will usually show spikey data at the same time.

[Stephen Dean]

Hi Cameron,

As per Davids email, I would be looking at the wiring and other sensors, to make sure that they are not pulling the 5V+ feed down.

[cameron]

Thank you for the advise, All the other sensors seem to be reading correctly via the logged data but I will now start the process of checking and testing all the wiring and sensor outputs.

Thanks again cam

[AdamW]

The photo is not a great one, but if I'm looking at it correctly, that bracket that is holding the tps sensor body looks a bit flimsy. How much can it flex? How much end float is there in the throttle shaft? Is the magnet still tight on the shaft? Those contactless sensors need the air gap to remain fairly constant.