Just a quick couple of questions:

1. I have been investigating the various DIY OBD ALDL-RS232 cables. I have found 2 types. 1 basic with a few resistors and transistors, and the 2nd has a more complex IC setup, presumably for the OBD 2 4th gen types.

Ques:
1. Which of the cables is required for data logging etc. on the OBD 1 system, and which baud rate is reqiured?


2. What baud does the 7165 use?

3. Do all TBI use 160 baud?


Thanks, Art

*Rest assured that I have made great use of the "Search" feature already.

 

1) It depends. There's a 1-transistor cable that works for 160-baud. There's a 2-transistor cable that works for 160 and 8192 baud. There's the MAX232/233 that works for everything as well. The one with the series diodes on the data line is good for the reflash of the 94/95 LT1 also.

2) The 165 uses both. It starts in 160 baud mode, and then when you send it a properly timed request, it switches to 8192 mode.

3) No. Later model TBI (93+ stuff with the 27C512 memcal) use 8192. But most of the 3rd gen stuff TBI is 160, yes.

 

So the 2 transistor cable will read both 160 and 8192 baud?

Sweet

 

Is this why Diacom would not read in anything other than special mode (IE. 10K across A-B)? I recall never being able to get anything more than the 160 mode and it would always idle at 1000RPM.

Mark.

 

I prefer the MAX232/233 cables. In datamaster I have not been able to get a 2 transistor cable to read up to the full 10 records a second where my MAX232/233 cable holds steady at 10 records a second. I could just as easily be doing something wrong though.

 

Thanks for the info.

Due to the simple ease of the 2 trans cable I think I'll try that for now.

What clock speed does the early TBI operate on?
Is the only problem with this setup then is the low comm rate for data logging etc. ?