tps wont relearn

[mtwolff]

i have recieved alot of advice on this forum and others- about an ongoing problem im having with a 2002 firehawk, and i greatly apprectiat all of it- but one common thing im being advised is to 0 out the tps at 3% throttle- ive tried unplugging the sensor clearing the code- and so on going through the relearn procedure- but when i plug the tech 2 in the tps goes back to 3% everytime- anyone have any advice, or suggestion on this one
thank you in advance for any help

[Aloicious]

i have recieved alot of advice on this forum and others- about an ongoing problem im having with a 2002 firehawk, and i greatly apprectiat all of it- but one common thing im being advised is to 0 out the tps at 3% throttle- ive tried unplugging the sensor clearing the code- and so on going through the relearn procedure- but when i plug the tech 2 in the tps goes back to 3% everytime- anyone have any advice, or suggestion on this one
thank you in advance for any help

I'd like to know this too, I reset mine, but after 1 drive cycle or so, it goes to 0.3 and stays there. I wonder if the TPS is starting to go?

[CoryF]

I found out with mine that it would never reset to zero because the TPS voltage was higher then 0.5v~0.6v. Once you get away from this voltage the PCM reads the Throttle percentage as 0.3%+.

The only way to get the TPS sensor to reset to 0.0% throttle is to make the TPS sensor output 0.5v~0.6v. There is a potentiometer inside the sensor and as the blade opens it sends a higher voltage to the PCM.

This problem often occurs because the TB was adjusted with the set screw. To get the sensor into this voltage range you can either close the TB blade back, which is probably not what you want to do because this is where it idles nice. OR I have heard of people drilling the mounting holes in the sensor to ovals so that you can rotate the sensor a little so that the potentiometer reads 0.5v~0.6v when the TB is resting on the set screw. The TPS sensor would have to be rotated counter clockwise to reduce the output voltage of the sensor.

The best way to measure the voltage from the TPS sensor is using EFILive Scan Tool, because this is the actual voltage the PCM sees. The PID is under Sensor--> Throttle Position Sensor Voltage. If you don't want to use EFILive, then there are 3 wires on the TPS Sensor:
-Gray: 5v reference (input)
-Black: Sensor ground (ground)
-Dark Blue: TPS Voltage (output)
Place an electrical tester on the Dark Blue wire and the Black wire this is the output voltage of the TPS Sensor, that the PCM gets. This voltage must be 0.5v~0.6v for the PCM to think that the throttle position is 0.0%

My Expierence: (Don't just go out and adjust your TPS to my settings, gather your own data, b/c each car is different)
Mine started out resting at ~0.613v which the PCM read as ~0.8%, according to my log 0.6v can read up to as much as 1.6% throttle. After some adjustments the TPS sensor voltage now rests at 0.549 volts which stays at 0.0% and doesn't tickle up any higher.


Hope this helps,
-CoryF

[joecar]

So the PCM won't relearn the TPS zero position if the TPS voltage is above 0.6V, am I understanding that correctly...?

Thanks.

[CoryF]

Yes joecar this is what I have found. I don't know what the exact voltage is but it is right around 0.6v ish

Unfortunately the Throttle Sensor Position Sensor PID only has one decimal place on the data page so you have to record the data and increase how many decimal places it shows in the Map.

***If there is a way to show more decimal places on the data page this would be MUCH easier! But I couldn't find a way to edit PID's that come built into EFILive. If there was a way then you could just monitor the data.

I had to create a map, and record the data here is how I set up my map:
Data:
-Parameter: Throttle Position Sensor Voltage (V)
Column:
-Column: Throttle Position Sensor Voltage (V)
-Col labels: ,value
Row:
-Throttle Position (%)
-Row labels:
,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19 ,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,3 6,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52, 53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69 ,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,8 6,87,88,89,90,91,92,93,94,95,96,97,98,99,100


Thanks,
-CoryF

[5.7ute]

Great post CoryF.

[joecar]

I don't know how to change precision on the Data tab...
but on the Dash tab you rightclick on the gauge/chart and go Properties, then:
- for gauge goto Fonts tab, click on Value, change Format from %.1s to %.3s
- for chart goto Series tab, click on Seriesn, change Format from %.1s to %.3s

Great post...

[CoryF]

I think the data page would have to be edited in the software. I remember when I was making the Calc_pids for my AEM Wideband there was a place for precision I think the column was called "Fmt". But there is no way to edit the pids that are built in to the program, maybe the next release could show a few more decimal places for the TPS Sensor Voltage.

Also on the Map tab if you create a map of the data there is a precision selection from 0-6 on the data tab of the map properties.

Thanks,
-CoryF

[Blacky]

You can edit the precision for generic PIDs (i.e. PIDs stating with SAE.xxxx)

For example, to change the SAE.TP PID you would need to change the SLOT definition for SAE.TP. The SLOT is UNM-08-61 and since that SLOT is used for many other PIDs, all those other PIDs will also have their default precision changed.

There doesn't seem to be much point in increasing the precision of SAE.TP, since the base value is a range from 0 to 255. That is converted from 0-255 to 0-100% using the expression:
% = (DATA*100)/255.
Typical values are:
0 = 0*100/255 = 0.000%
1 = 1*100/255 = 0.391%
2 = 2*100/255 = 0.784%
3 = 3*100/255 = 1.176%

So you can see that although it might appear that you're getting greater precision, the actual precision is about +/- 0.4

Anyway, if you still want to do it, change this:

*UNM-08-61
 %                 0.0         100.0      .1   /      2.55          0.0

to this:

*UNM-08-61
 %                 0.0         100.0      .2   /      2.55          0.0

in \Program files\EFILive\V7.5\Configuration\sae_generic.txt

Changes to sae_generic.txt will be overwritten when any new update is applied.

Version 8 will allow you to configure gm enhanced PIDs as well.

Regards
Paul

[Blacky]

Ignore my last post, its the GM.TPS PID you're logging (not SAE.TP). You're in luck, the voltage PIDs use the SLOT definiitons from sae_generic.txt so you can change this:

*UNM-08-900
  V                 0.0          5.0      .1   /      51.0          0.0

to this:

*UNM-08-900
  V                 0.0          5.0      .2   /      51.0          0.0

in \Program files\EFILive\V7.5\Configuration\sae_generic.txt

Regards
Paul