Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

Is my TPS voltage weird (And the associated ripple effects of the weird)

General Tuning Discussion

Forum Posts



Tech Articles

Discuss all things tuning in this section. News, products, problems and results. 

= Resolved threads


Heya - it appears that I've gotten the cam control "happy" and accurate enough to not stress over (ok - im super happy but its cam control and no-one really cares that much lol) - onto the next part of my tuning experience - time for that fueling stuff again :)

So i have a few questions

ECU setup is map not maf on a haltech - on gear changes at full noise - as the throttle snaps closed you get a rich spike - cool - no worries - but as it snaps open you get a lean spike - is that normal - or is that relating to the next questions I have.

I'm seeing that the tps voltage is floating around at closed throttle with the engine turned off - with a range of 0.45v -> 0.50v.

As a result - the data channel tps-d (rate of tps change in deg per sec) reads anywhere from -300deg a sec to +300deg a sec with it constantly jumping wildly around - this happens at any steady state throttle position - altho at 100%tps the voltage only jumps around in the range of 0.03ish volts of unsteady-ness instead of up to 0.05v

I've tried two tps sensors (factory wiper arm style and aftermarket hall effect style) and when they are not even connected to the throttle body, i get the flaky voltages.

With the tps-d changing so much - it seems that transient throttle is going all to wack - to the point where if you disable transient throttle (yeah - not nice for drivability) the fueling gets a LOT smoother eg the ecu is not thinking theres tonnes of tps changes per second that it needs to correct fueling for.

I've tried applying filtering to the tps-d and the tps channels and it doesnt help at all.

I get the feeling this could be a rabbit hole that will ruin sleep and create ocd nightmares so I'd like to avoid that if possible ...so my questions are now

is the flaky voltage "normal" - i'm guessing its not - but how stable is the tps output voltage from the sensor on other peoples cars?

if the voltage is not normal - and it happens on two different sensors - on or off the throttle body - with engine on or off - where should i start to look for the problem? sensor grounds? shorts to ground? voltage stability to the sensor? the signal wire between sensor and ecu? (Says me hoping to narrow it down with advice from here and not to have to spend a day with a multimeter and hacking into wiring looms)

if i sort this out and get a stable tps voltage - i'll be able to get the transient throttle stuff better and will i hopefully be able to reduce / eliminate the lean spike after applying throttle again when driving it with some enthusiasm?

So halp - does anyone have any ideas on where to check first and what to look for? Gord - your always good with ideas and angles that may have been missed - any input you can offer here?

Looks like I'm going to spend a bit of time this weekend logging raw inputs and investigating wiring looms and what sensors are powered and where that power comes from and how stable is it etc etc - its a pain that i dont have this historic data to look back on but from memory the tps voltage has always been a bit floaty but any input from the people on the forums here is going to be helpful methinks :\

anyways - hope your all having fun and your projects lack rabbit holes of doom - catchyall laters

Might be important to provide some information on what model / vintage Haltech ECU you are using, firmware versions, etc. There may be known issues, particularly when you mention that applying filtering has no effect.

How stable is the 5V power supply and sensor ground used for the TPS sensor. Best way to look at this would be an oscilloscope.

Often there is a scaling parameter for the delta-tps, sometimes even a way to ignore small changes, such as minimum change (2-4%) that may help.

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?