GST with PSI
DSM Wiseman
- 2,729
- 1,509
- Jul 27, 2005
-
San Diego,
California
A mechanically sound car is the cornerstone of any good tune. Things like boost leak tests, setting base timing, and base fuel pressure are just some of the commonplace things that are checked to ensure the car is ready for the road, and certainly before a performance tune. If one of these is out of wack, it can affect many other systems, as well as performance and driveability overall.
The throttle position sensor (TPS) should be properly adjusted just like any other mechanical system on the vehicle. Although the ECMlink TPS Adjust feature will allow the user to scale an improperly calibrated TPS, it was never intended to serve this function. The TPS Adjust feature was intended to correct for sensors that are slightly out of position, or for an aftermarket/non-stock TPS. The TPS Adjust feature was NOT intended to alleviate the user from having to adjust it properly.
Now, considering the statement above, the ECMLink TPS Adjust feature has become a pet peeve of mine. Nearly every log I look at, somebody is using it incorrectly. That being said, nothing is stopping you from using the feature incorrectly, just know, you're using it incorrectly. I strongly believe if you need to adjust the TPS offset or TPS scale more than a value of 2 on either scale, you need to go back and make a manual adjustment to your TPS. Say for example, you are at an 8 offset, on a 103% scale. That tells me the natural sweep of your TPS sensor is out of wack, and you need to go manually adjust it. On my personal cars, I'm happy when this feature is either disabled, or I'm at 0 and 100%...But that's just me.
Additionally, I've seen TPS sensors that are scaled cause some wacky issues. I've helped tune a few cars that had idle issues that I believe were directly linked to the TPS being out of wack. In a few of these cases, the user was employing the TPS Adjust feature to compensate for an improperly adjusted sensor. After having the user simply adjust the TPS properly and disable the scalar (IPS settings remained functioning properly and unchanged), I was able to dial in idle and cruise without issue. Now, many of you may not have this issue, but I think it's definitely worth mentioning.
Here's the bottom line: There's no substitute for a properly functioning/adjusted TPS. Fully closed, your TPS should read approximately 0.63v (RawThrotPos of 32) when logged in ECMlink. Open, it should read anywhere between 4.6v to 5v.
Making manual adjustments to the sensor is as easy as loosening 2 bolts, tweaking the sensor until it reads the proper voltage, then tightening the the bolts back down. There's a good video outlining this procedure here:
In summary, if you're asking for log advice and I'm bitching at you to fix your TPS, this is why.
Other helpful links:
http://www.ecmtuning.com/wiki/v3tpsadj
https://www.ecmtuning.com/wiki/dsmlinktpsadjustment
The throttle position sensor (TPS) should be properly adjusted just like any other mechanical system on the vehicle. Although the ECMlink TPS Adjust feature will allow the user to scale an improperly calibrated TPS, it was never intended to serve this function. The TPS Adjust feature was intended to correct for sensors that are slightly out of position, or for an aftermarket/non-stock TPS. The TPS Adjust feature was NOT intended to alleviate the user from having to adjust it properly.
Now, considering the statement above, the ECMLink TPS Adjust feature has become a pet peeve of mine. Nearly every log I look at, somebody is using it incorrectly. That being said, nothing is stopping you from using the feature incorrectly, just know, you're using it incorrectly. I strongly believe if you need to adjust the TPS offset or TPS scale more than a value of 2 on either scale, you need to go back and make a manual adjustment to your TPS. Say for example, you are at an 8 offset, on a 103% scale. That tells me the natural sweep of your TPS sensor is out of wack, and you need to go manually adjust it. On my personal cars, I'm happy when this feature is either disabled, or I'm at 0 and 100%...But that's just me.
Additionally, I've seen TPS sensors that are scaled cause some wacky issues. I've helped tune a few cars that had idle issues that I believe were directly linked to the TPS being out of wack. In a few of these cases, the user was employing the TPS Adjust feature to compensate for an improperly adjusted sensor. After having the user simply adjust the TPS properly and disable the scalar (IPS settings remained functioning properly and unchanged), I was able to dial in idle and cruise without issue. Now, many of you may not have this issue, but I think it's definitely worth mentioning.
Here's the bottom line: There's no substitute for a properly functioning/adjusted TPS. Fully closed, your TPS should read approximately 0.63v (RawThrotPos of 32) when logged in ECMlink. Open, it should read anywhere between 4.6v to 5v.
Making manual adjustments to the sensor is as easy as loosening 2 bolts, tweaking the sensor until it reads the proper voltage, then tightening the the bolts back down. There's a good video outlining this procedure here:
You must be logged in to view this image or video.
In summary, if you're asking for log advice and I'm bitching at you to fix your TPS, this is why.
Other helpful links:
http://www.ecmtuning.com/wiki/v3tpsadj
https://www.ecmtuning.com/wiki/dsmlinktpsadjustment
Last edited: