I can and want to do this now... But I have no idea which one it is...

Is it this one...
http://www.tbichips.com/cable.htm

Or one of these?
http://winaldl.joby.se/aldlcable.htm

Ive also seen a few other. So which ones have the ppl around here use?

It must also work with the serial to USB adapter...

91' 305 TBI T5

 

The ones shown on JoBys site work well (never tried w/ an adaptor, though). The A-B resistor will not be necessary as the ECM continuously transmits data.

The other option is to use the USB OBD-1 cable from moates.net. That, too, should work fine with the older TBI computer.

 

I've used and well use on my test bench currently a MAX232 chip based interface cable. I have used it with both 160 and 8192 baud datastreams.
I have not had a problem with it.

I plan to build a two transistor interface to see how it works.

 

Price is the major issue, and thats why Ive gotta make my own. Do I have to have the 12v power source (one schem doesnt hav it)? I wonder if the USB will tranfer power through the adapter just as the serial would.

I have no idea what you just said.

 

I believe this is what he was referring to: http://www.techedge.com.au/vehicle/aldl8192/8192hw.htm

It's just a different interface, uses a chip from a company called Maxim, and a few other parts (voltage regulator, capacitors, and some resistors) rather than a couple transistors and resistors. I ended up using this because I couldn't get the two trans. to work. Granted, I didn't really give it a chance... If I remember correctly, the advantage to the MAX232 setup is that it does a better job of outputting the correct signal voltages for RS-232 (serial port) communication.

As far as I know, USB is 5 volts.

I wish I could be of more help, but I never really used the two transistor interface and I have never adapted to USB. However, I think I've read that some people are having better luck with certain serial-USB adapters than others... Good luck.

 

Thanks for the info! That first schem looks a little bit much for me. So looks like Ill have to do the schem on JoBys, the one with the external power supply. To bad a fuse blows everytime I put one in for the cig lighter...

 

what kind of supply are you plugging in? if it's like one for a laptop, the supplies for some reason reverse polarity and once you connect a laptop up to the system ground(chassis), you will pop the fuse. I've done that a few times now, so I use an inverter with the ac brick on my laptops.

you are much better off using the transciever chip (232) rather than the 2 transistor, if you can manage that. the 2 transistor is hit or miss sometimes.

 

I havent pluged in the laptop. Just say a radar detector or cig lighter and it pops. Now I dont plug in anything and it pops!?

My abilities are not well off enough to make the 232. Maybe Ill find someone here selling the USB cheap enough. Ill head off there now, or post in wanted sub-forum...

 

sounds like the lighter socket is bad or something. there might be some crud in there, I have seen where plugging in the jack will accidentally short the socket out somehow, leading to a popped fuse......maybe you can install the plug, then put a fuse back in once it's fully seated?

yeah, you are better off with the 232 circuit, but don't feel like you can't try building the 2 transistor unit. worst case is you are out a couple bucks and it doesn't work.

 

Thanks for the reply. Ive checked an old thread about the short. And most agree its the cig lighter, apparently common.

I heavent heard of anyone having issues with the transistor setup, until now, but thats the L03 TBI guys. Are you guys TPI? Maybe thats the issue.... Just a thought.

 

nah, it's the same either way. it's just the 232 circuit is more robust, and closer to the actual specified performance for the aldl port. the 2 transistor depends on the parts you use, and how well you constructed it, as well as the wiring in the vehicle being in good shape.

 

Well I think its apperent that my wireing has seen better days. Guess Ill give it some more time and see what comes up.