Computer Diagnostics and Tuning Technical discussion on diagnostics and programming of the F-body computers

Scan9495: Free OBD1 scan app for 93/94/95 LT1

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Old Jun 23, 2015 | 09:25 PM
  #286  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

Just as a reference, my tech 2 displays it both ways at once. Does that mean the tech 2 is taking 1 piece of info and displaying it 2 ways?

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Old Jun 23, 2015 | 10:20 PM
  #287  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

Yes, I explained the details in post 284 above.
Old Jun 23, 2015 | 10:27 PM
  #288  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

With the program's .csv file saved in excel format, add columns next to the A/C pressure, and use Gary's formula (and the sensor calibration) to convert the pressure to voltage to lambda to A/F ratio.

Last edited by Injuneer; Jun 23, 2015 at 10:30 PM.
Old Jun 23, 2015 | 10:40 PM
  #289  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

Originally Posted by Injuneer
With the program's .csv file saved in excel format, add columns next to the A/C pressure, and use Gary's formula (and the sensor calibration) to convert the pressure to voltage to lambda to A/F ratio.
Lol, Thats not going to happen. I can barely save and view a log file.....
Old Jun 24, 2015 | 08:57 AM
  #290  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

Version 2.2.0 is posted. It changes the "RPM filtered" reading to "A/C pressure (volts)". Loading older version log files with this version will have the wrong readings for A/C pressure in volts. Conversely, loading new log files with an older app than 2.2.0 will have the wrong readings for RPM filtered, but I doubt if anyone was using it anyway.

FYI, as of a few versions back, all log files have the app's version number at the front of the file. But that number is not used by the app, so you will have to view it to see the version of the app that created the file.
Old Jun 24, 2015 | 11:04 AM
  #291  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

One of the first things I do in Excel when I get a log to review is "hide" the columns I'm not really interested in, including "RPM Variation %" and "Engine RPM Filtered".
Old Jun 24, 2015 | 09:05 PM
  #292  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

Thanks so much for the added parameter, I really appreciate it. I wonder what rpm filtered is? Its not listed in the tech2.
Old Jun 25, 2015 | 08:19 AM
  #293  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

I think it deals with how many bits of resolution are used. The 8-bit format limits the display to 25 RPM increments = format for "Engine RPM Filtered" - the data log entries in this field are always in 25 RPM increments.

May be using the Opti high res pulses to interpolate inside the 25 RPM increments to get "Engine RPM" - displays in discrete RPM. Or it may be using an expanded 16-bit field. In Datamaster, the discrete RPM entry is labeled "RPM-16". Not sure though.

Gary may have more insight into this.
Old Jul 8, 2015 | 10:51 AM
  #294  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

So with this i'm able to see why i've had an airbag light for the past 2 years? lol
Old Jul 8, 2015 | 11:52 AM
  #295  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

Gary indicates it will work. I have looked at a lot of data logs, but have never used the system myself, because I really don't use the stock PCM any more for anything other than the speedometer and the IAC valve.
Old Jul 11, 2015 | 03:01 PM
  #296  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

I ordered my FTDI cable but when I cut it open today, I have no white wire. The pin out on the opposite end from the USB is black-brown-red-orange-yellow-green. What color should I be using in place of white? Thanks!
Old Jul 11, 2015 | 03:30 PM
  #297  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

You may want to contact the developer of this system directly, using the link at the bottom of post #1.
Old Jul 11, 2015 | 03:57 PM
  #298  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

Thanks Fred, I just dropped him an email.
Old Jul 11, 2015 | 10:37 PM
  #299  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

Originally Posted by curly
I ordered my FTDI cable but when I cut it open today, I have no white wire. The pin out on the opposite end from the USB is black-brown-red-orange-yellow-green. What color should I be using in place of white? Thanks!
I responded to curly's email.

For others with the same or similar issues: If I remember correctly, in this case, you substitute the orange wire for the white one. The goal here is to jumper the TXD and RXD signals together and feed those to the car's data pin connector. If you have a signal diagram for an adapter (or markings on the circuit board), you may be able to figure out which wires to use.
Old Jul 27, 2015 | 09:36 AM
  #300  
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re: Scan9495: Free OBD1 scan app for 93/94/95 LT1

GaryDoug, any interest in porting your excellent program over to an Android and Apple Smartphone? That's something I'd pay for!



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