OBDII Throttle position display meter

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TXBDan
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OBDII Throttle position display meter

Post by TXBDan » Wed Apr 24, 2013 9:29 pm

Hello,

I've been playing with HLT with my iPhone 4S, GoPoint BT1 OBDII sender, and a 2010 VW GTI. One thing i've notice is that it seems like the green bar graph of the throttle position seems to go to max very easily. For example at around 2/3rd throttle it shows a full green bar. I know its not fully throttled because i can hold it there and then push the pedal down harder and the car will go faster. I see in the data logs that the throttle position value is a decimal between 0 and 1 so its not like there is a random maximum value that must be calibrated, etc. Or is that done behind the scenes before the data log is created? Any ideas?

Thanks a lot,
Dan
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Harry
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Re: OBDII Throttle position display meter

Post by Harry » Wed Apr 24, 2013 9:36 pm

OBD defines throttle comes in at values between 0 and 255 (mapped to 0 to 100% or 0.0 to 1.0 in LapTimer). Problem is cars do not use the defined range and instead deliver e.g. values between 4 and 120... This is the reason LapTimer auto calibrates min and max values: It initially sets a low max expectation (need to check the sources for the exact value) which is treated to be 100%. In case a value higher than the expected max value is received, the 100% calibration is shifted up. This means you will have your throttle calibrated once you have fully pressed the pedal once - which is an easy task on track ;-)

- Harry
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TXBDan
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Re: OBDII Throttle position display meter

Post by TXBDan » Wed Apr 24, 2013 10:00 pm

Ah nice. i wondered that and definitely saw an improvement after i floored it once. I still feel like i was saturating a bit early, but i'll use it some more and see.

Thanks!
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bulls23
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Re: OBDII Throttle position display meter

Post by bulls23 » Thu Apr 25, 2013 8:03 am

Just being curious:
Does the throttle PID really show the actual pedal position or the throttle body position / engine load. With all that drive by wire stuff the actual pedal position doesn't mean the engine is doing the same ;)
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Harry
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Re: OBDII Throttle position display meter

Post by Harry » Thu Apr 25, 2013 8:11 am

The throttle PID 0x0111 delivers your pedal position + what engine control believes is necessary. You can switch to pedal position PIDs in LapTimer's expert settings (0x0147 to 0x014B) if you want. Please check what you car has available first (Sensor List -> touch row showing your active OBD - so you need to do this with your iPhone connected to your OBD with the engine on). A description of the different PIDs is available here: http://en.wikipedia.org/wiki/OBD-II_PIDs

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Re: OBDII Throttle position display meter

Post by G_Rossney » Sat Jan 26, 2019 6:34 am

Harry wrote:
Thu Apr 25, 2013 8:11 am
The throttle PID 0x0111 delivers your pedal position + what engine control believes is necessary. You can switch to pedal position PIDs in LapTimer's expert settings (0x0147 to 0x014B) if you want. Please check what you car has available first (Sensor List -> touch row showing your active OBD - so you need to do this with your iPhone connected to your OBD with the engine on). A description of the different PIDs is available here: http://en.wikipedia.org/wiki/OBD-II_PIDs

- Harry
So I can do this for many of the PID if I have the correct ID for the PID. For instance;
Throttle ID: 0x140
Brake Pressure ID: 0xD1
Oil Temp ID: 2101
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Harry
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Re: OBDII Throttle position display meter

Post by Harry » Mon Jan 28, 2019 4:06 pm

To not mislead others: the PIDs named are incomplete or not correct. 0x140 will be interpreted as mode 1, PID 0x40 - which is the channel documenting which of the mode 1 PIDs 0x41 to 0x60 are available. So strictly speaking, it is no PID at all. The alternative throttle PIDs are mode 1 0x47 to 0x4B as written above. These are all standard PIDs. 0xD1 is no standard PID and at least incomplete, 2101 is interpreted hex (i.e. should be 0x2101 when using the same syntax as the other PIDs) and will retrieve the full array of custom PIDs for Toyota, Subaru, Scion makes.

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Re: OBDII Throttle position display meter

Post by G_Rossney » Fri Feb 22, 2019 11:31 pm

I'm trying to figure out how to set the information in Harry's for throttle and brake for my Subaru BRZ (2013). I've found PID information for a number of items, I just can't seem to find (in app, in PDF doc or in forum) how to set the proper information. Can someone share where I can find a tutorial?
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Re: OBDII Throttle position display meter

Post by PitrsRS » Sat Feb 23, 2019 12:50 am

I usually used for throttle PID D, but after last update it doesn't work any more :-\
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Harry
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Re: OBDII Throttle position display meter

Post by Harry » Sat Feb 23, 2019 6:00 pm

PitrsRS wrote:
Sat Feb 23, 2019 12:50 am
I usually used for throttle PID D, but after last update it doesn't work any more :-\
Not related to the last version. I know new versions are often suspects to all kinds of issues, but this is some other configuration issue. ;) I use Position D all the time and it is definitively working. I even started the engine a few minutes ago to make sure.

- Harry
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