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TPS Adjust

This extension does a simple calculation of the TPS adjustments necessary for a given datalog. The idea here is that the ECU has some “opinion” of what the observed throttle position sensor value should be when your foot is off the throttle entirely and when the throttle is floored. But often this isn't true simply because the TPS may be slightly out of position or maybe you have a non-stock TPS to begin with.

Regardless of the reason, this adjustment helper attempts to correct the problem for you by rescaling and offsetting the throttle position seen by the ECU.


To use this function, just grab a log with throttle position data (TPSVolts or ThrotPos) ranging from fully closed (foot completely off the throttle) to fully open (foot to the floor). The engine does not have to be running to capture this data.

Once you have a log with this data, simply right click in the log (graph screen) and select “TPS Adjust”. You'll be presented with a tab showing the suggested new values for TPS adjustment. Review this data to make sure it seems reasonable before you hit Save to ECU…

Note that with ECMLink V3 installed in your ECU, throttle position data is always captured so you do not have to manually add anything to the captured values list. V2 users will simply need to check the ECU→Captured values dialog to make sure ThrotPos is logged.

Optional: Simulate Idle Sw

After this adjustment has been done properly, you can optionally enable the “Simulate idle switch” checkbox to simulate idle switch operation based on throttle position. Doing so makes the ECU ignore what the physical idle switch pin coming into the ECU indicates and instead simulates the value based on throttle position. This also frees the idle switch input pin to the ECU for other purposes, such as switching in auxiliary timing/fuel maps and/or secondary fuel adjustments (dual banks or dual fuel types).

v3tpsadj.txt · Last modified: 2009/12/19 06:04 by twdorris