OBD1 scan program for free

63972 Views 136 Replies 26 Participants Last post by GaryDoug, Sep 1, 2018

GaryDoug

Discussion Starter · Mar 20, 2013

Starting a new topic and this is copied from the "OBD2 scan program for free" topic:

I am well along in writing an OBD1 scan program for the 94/95 LT1 F-series cars. It will contain more data than the Freescan app and about the same basic material as Datamaster (a few less "cute" features) when done. I will add some bi-directional actuators as well: Fans, A/C, MIL, evap purge, EGR duty cycle, AIR pump, and closed/open loop mode. Most of it is already working but I will take some time to dress it up and add some graphs (maybe) and datalogging before offering it for free. Anyone who wants to try it now (or at any time) can just ask.

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GaryDoug

Discussion Starter · #2 · Mar 20, 2013 (Edited)

I placed the first beta version in the same folder with the GDScan app:
My Files
The filename is Scan9495.zip.Two files, just place them in the same folder. No dialoging at this time (edit:added later). Many actuators though, something the others don't have. This version is for the automatic, but I can adapt it to manual. For those with a newer pc and no serial port, you will need a USB-type cable. You can make you own setup for about $20-30. let me know if you want instructions.

GaryDoug

Discussion Starter · #3 · Mar 20, 2013

An OBD2 cable will NOT work on any F-series car before 1996. It is a completely different format.
There are a few ways to go to get one that will work. The simplest way is to buy one already made like this one: ALDL OBD1 OBD cable OBDI OBD2 engine codes
The only difference in these two is the different connector at the car's end (12 pin versus 16 pin). Another way to go that is cheaper but harder is to buy an FTDI-based USB-to-serialport adapter [ame="http://www.amazon.com/Chipset-Speed-Serial-RS-232-Converter/dp/B005S72HHO/"]

[/ame] Amazon.com: FTDI Chipset High Speed USB 2.0 to Serial RS-232 DB-9 Converter: Computers & Accessories
for newer PC's without a com port, or a simple 9-pin serial cable if your PC has a com port. In either case you would then have to build a simple 7-component circuit to perform the interface to the car. I can supply the details if you want.

http://www.ls1lt1.com/forum/members/...st-cables.html

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bobdec

· #4 · Mar 20, 2013

Gary, cranked up the program on my bench test PCM w/ my XP laptop seemed to work OK. Should I be running it in emulation (95/98/2000). I have to play with my resolution settings as it does not completely on my screen, no scrollbar yet. I'm using a Arduino FT232RL USB to Serial Module instead of a ALDL cable. I'm wired USB-FT23RL-PCM directly. I will put some feedback together an PM you when I can get it organized. So far so good I like the looks of the display. Any specific input you are looking for at this stage..??

GaryDoug

Discussion Starter · #5 · Mar 20, 2013 (Edited)

I think it should be ok with XP now without any emulation. It works ok on my older XP PC. The O2 sensor values should be around 450 (mv) and the BLM and INT values are probably 128, all with nothing attached. The PCM VIN should look correct. I am actually needing someone to test it on a car so that the ABS and SIR modules are present, to make sure they won't cause any conflict. If I can confirm it works well, I will continue with the development.
There is a word missing from one of your sentences. What did you mean here: "it does not completely on my screen". Does not... FIT, FILL, ?

Thanks

sorry for all the edits...

Abrown2006

· #6 · Mar 21, 2013

Hopefully Ill have my transmission back together and in the car saturday. If no other problems Ill give it a shot and see how well your program works.

bobdec

· #7 · Mar 21, 2013 (Edited)

Gary.. I was saying the display does not fit on my laptop, an older IBM T30 I use for tuning. The right side O2 data is cut off. My laptop screen is 11 wide by 8 1/2 high using 1024 X 768 resolution, normal font size and 32 bit color settings. I can not make the display any wider, I can drag the window up/down & left/right Ok, but grabing the right border trying to see O2 data only expands to the pic below and then stops. It works fine on my desktop with a 23 wide screen the window requires 12 inches of width to see everything.. The pic below is a simulation of what I see on the laptop sent from my desktop.

By the way RPM=50, RPM scaled = 45, desired RPM = 3188, ignition voltage 11.8 (using old PC AT power supply) are displaying correctly. Not sure what 'Min IAC' is, it is 112, looks like IAC park as coolant temp is -40 w/o being connected. Scans engine at 95 Ms, tran at 79 Ms and both at 175 Ms. If I can get display working I'm ready to try it w/ the ALDL cable on my car, as I have a spare PCM already programmed I'm not to worried..

[/IMG]

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Mystery Bird

· #8 · Mar 21, 2013

Will it have the ability for custom inputs? For example setting up wideband input from the AC port.

GaryDoug

Discussion Starter · #9 · Mar 21, 2013

bobdec said:
Gary.. I was saying the display does not fit on my laptop, an older IBM T30 I use for tuning. The right side O2 data is cut off. My laptop screen is 11 wide by 8 1/2 high using 1024 X 768 resolution, normal font size and 32 bit color settings. I can not make the display any wider, I can drag the window up/down & left/right Ok, but grabing the right border trying to see O2 data only expands to the pic below and then stops. It works fine on my desktop with a 23 wide screen the window requires 12 inches of width to see everything.. The pic below is a simulation of what I see on the laptop sent from my desktop.

Bob,

Thanks very much for the detailed feedback. It is appreciated greatly. First, I would try resetting the screen resolution if you can. But I have actually duplicated the problem here with my other PC. So I will be working on fixing that today. It may be a simple as locking the right side of the tab display to the right edge.
I would love to see your setup as I think it must be like mine. What are you using for a signal source for the setup? I have programmed a 19 pin PIC device to provide several signals (Opti (hi and lo res), VSS, O2's, MAF, and VATS) and be varied from a pot, which can be either the TPS input or a separate one (RPM). I could give you one if you like; they're only about $1 each.
In order to expand the capability, I ordered today a used ABS module and will see if I can get DTC's and parameters from it also.

Gary

GaryDoug

Discussion Starter · #10 · Mar 21, 2013

Mystery Bird said:
Will it have the ability for custom inputs? For example setting up wideband input from the AC port.

I don't really know what that is. What are you using now for custom inputs, anything? I think the problem is getting an A/D converter into the adapter cable, unless you are aware of some capability of the PCM that is undocumented(?). Unless...
What is this "AC port" reference? Does that involve using the AC temp or pressure input to read other signals? Sounds interesting.

Abrown2006

· #11 · Mar 21, 2013

GaryDoug said:
I don't really know what that is. What are you using now for custom inputs, anything? I think the problem is getting an A/D converter into the adapter cable, unless you are aware of some capability of the PCM that is undocumented(?). Unless...
What is this "AC port" reference? Does that involve using the AC temp or pressure input to read other signals? Sounds interesting.

I could be wrong but maybe hes talking about the a/c pressure switch input when people use it to monitor a wideband o2.

GaryDoug

Discussion Starter · #12 · Mar 21, 2013

Abrown2006 said:
I could be wrong but maybe hes talking about the a/c pressure switch input when people use it to monitor a wideband o2.

Makes sense, maybe use the a/c temp sensor for a 2nd one? I assume the ac is not present or used in the car. I would like to learn more.

GaryDoug

Discussion Starter · #13 · Mar 21, 2013

I just uploaded a new version with the screen size set to just under 1024x768. Hope that works better.

Mystery Bird

· #14 · Mar 21, 2013

Abrown2006 said:
I could be wrong but maybe hes talking about the a/c pressure switch input when people use it to monitor a wideband o2.

You got it correct.

Abrown2006

· #15 · Mar 21, 2013

GaryDoug said:
Makes sense, maybe use the a/c temp sensor for a 2nd one? I assume the ac is not present or used in the car. I would like to learn more.

People wire a relay to toggle between a/c pressure switch to the wide band when datalogging then switch it back through the relay when needing a/c. Theres a few write ups on it

GaryDoug

Discussion Starter · #16 · Mar 21, 2013

Abrown2006 said:
People wire a relay to toggle between a/c pressure switch to the wide band when datalogging then switch it back through the relay when needing a/c. Theres a few write ups on it

Thanks guy, you were very helpful, unlike some.

Abrown2006

· #17 · Mar 22, 2013

GaryDoug said:
Thanks guy, you were very helpful, unlike some.

No problem. Im not a pro at tuning or know everything there is but Ill always give any advice that I know is true.

Mystery Bird

· #18 · Mar 22, 2013 (Edited)

Here is a pretty good write-up on what I was trying to say.

Logging wideband O2 with stock PCM and Datamaster – WRITEUP - CamaroZ28.Com Message Board

http://www.ls1lt1.com/forum/pcm-tun...63-tts-datamster-interface-lc-1-wideband.html

Oh, no need for comments like this either, I don't have as much time as others may.

GaryDoug said:
Thanks guy, you were very helpful, unlike some.

bobdec

· #19 · Mar 22, 2013

Gary detailed info an WB topic.. TTS Datamaster EE has a utility to add a display value .. you select the scan data stream offset value (byte #30 in Datamaster), then build the equation to calculate the display value, and name the display AFR.
A/C pressure is a 0-5 volt input to the PCM on pin C23, it is an 8 bit field at offset 26 or 27 Decimal (i think) in the scan data stream. 0 volts = -14.95 PSI and 5 volts = 452.459 PSI the equation is PSI = N * 1.83300 - 14.9500 . To convert C23 to AFR in Datamaster you put a switch on the feed to pin C23 that allows switching the wideband 0-5V output to pin C23 of the PCM. The Datamaster allows you to write a new equation. Since the WB should read 0 volts = 7.35 and 5 volts 22.39 the new equation s/b AFR=(3.008*0.0196)*N + 7.35 as per the post referenced by Mystery . To do this you would have to add a new display box, add a utility to identify the data scan offset and an equation to calculate the display value and name it.
Very key is the ability to create a recording of the log data and ability to play it back so the user can correlated AFR to specific operating conditions. Brings up a point are you planning a log to storage like Freescan, it creates a CSV file.

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GaryDoug

Discussion Starter · #20 · Mar 22, 2013 (Edited)

Bob,
I am absolutely not done with this app as long as I can verify that it works ok in an actual car. I really don't want to waste any more time and effort if there are basic problems to overcome first. I don't expect any problems but I can't be sure yet. As soon as I can verify operation, I can continue. BTW, I will add some ABS functions also, if my plans work out (module on order now).

It should be easy enough to supply the readings for an alternate PID (AFR). What I don't know is what becomes of it later, i.e. what is the goal for this app. From your description, I am assuming I would provide a table or graph showing the new PID and some others, unspecified as of yet. I was about to ask the forums for suggestions on the format for the datalogging, in order to make it as compatible as possible with others already in use. My first choice was Freescan, since it is a fixed format, while Datamaster is highly configurable and set by the user.

I see that data byte 26 is the A/C evaporator temperature (another possibility) and byte 27 is the A/C pressure, which are for the 94/95 LT1 of course.

Btw, I think this can be a good thing to be able to talk directly with the developer whenever you want.

Also....I am not getting email notices when someone replies to this topic. Is that supposed to be working, and does it work for you guys? I have checked my setup for proper email address and notification setting and it looks ok.

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