Parallax USB-RS232 converter (DIY ALDL ODB1 cable)

[yoda69]

This may be a long shot, but try the following:
1. Load the ads file using "Acquisition" and then "Import Definition".
2. It will prompt to save as ADX, just follow prompt.
3. Select "Acquisition" and "Edit Definition"
4. Select "Values" and the select "Engine Speed"
5. Change "Command Association" dropdown from "All" to "Transmit Stream Reply"
6. Save ADX

Try and log now and see if Engine Speed looks OK in the log, if it is, you will need to do the same with all the other data variables under "Values" and "Bitmasks".

Good Luck,
yoda69

[cidium]

I did some searching for a copy of TP4 and came up with a goose egg. On the TP website they don't offer TP4 download, so any ideas where to get a copy?

Gave it a try yoda and nada, the item list, engine speed is just cycling values from 0 - 4500. All the other values are jumping around too.

[yoda69]

There maybe a bit more to getting it working, follow up Robert and the TP forum and see if he can update to the TP5 adx format, as he is mnore experienced than anybody else with these.
Should be able to download TP4 from here.
http://www.tunerpro.net/downloadAppLegacy.htm

[cidium]

Now the problem is TP4 can't connect to the ECM. I am using the Max232 / 2 transistor setting on 10hz - com port is still 4.

This is frustrating, lol, this DIY isn't for the short attention span people~

[antus]

What your doing sounds right, im not sure why it wouldnt be working for you. It might be better to ask on the tunerpro forums if anyone can help you out with exactly what you need for your car. If you find out whats wrong, update this thread for others that may land here. There may be a resistor or something for your model, but I dont think anyone here has tried it (most of us are Australian).

[cidium]

Here's a bit of an update....

I have been posting at the TP forums and haven't had much success getting answers. I also have been exchanging emails with robert saar, he's been really helpful. I have concluded the parallax USB to serial converter and TP4 doesn't like the 2 transistor ALDL to serial circuit. So, my next move is to use a max chip circuit between the OBD1 port and the parallax converter. Since robert was the one that wrote the ADS file I am trying to use I thought he would know if TP5 could convert the file and render it useful. He confirmed that TP5 might have issues converting the ADS to ADX and it would be best to use TP4 for ADS files. As soon as I can get a chance to run TP4 with the max circuit I'll give a heads up to you guys.

peace~

[cidium]

Well, the max circuit between the OBD1 and Parallax circuit returned a failed connection in TP4. I was able to get a connection in TP5, but was getting the strange cycling data. I am just about to say "F" this~

[cidium]

Update:

It works finally. The deal is I had a diode on the TX line of the max circuit for one way transmission. Decided to take that diode off and now it works. Final configuration - home made OBD1 connector, schmartboard TTL to Rs232 ( http://www.schmartboard.com/schmartboar ... ematic.pdf ), Parallax USB to serial converter ( http://www.parallax.com/Store/Accessori ... fault.aspx ), Tunerpro v4, A178 ADS file from ( http://tunerpro.net/gmOBDI.htm ). Test truck, 92 S10 blazer 4 door 4x4 (vin W)

total cost: schmartboard and parallax converter - 33.00 usd
................. connector parts - 2.95 usd

Finally thoughts - buy a pre-packaged OBD1 cable, it will save you alot of frustration~