brucec59

Where can I get the rectangular OBD connector? I tried Radio Shack and Mouser, searching for "OBD" but no luck.

Thanks.

maurice97C2S

Try here .. waiting for mine now ..

cheers, Maurice

http://www.obd2cables.com/products/p...products_id=43

tj90

All I can find is 1.8V. I built the board with these and will try it. If it does not work, ill just short them out and try again.....

raycm

LED's.
I don't know of any standardized/spec'ed part numbers for LED's. (Like 2N3904)
Do I guarantee that your LED will work? I understand what is involved in being sure it will or wont work. Therefore I know the answer to "will 1.4V, 1.8V, or 2.2V work". Probably in most situations but not all. Adding the LED was an after thought for your benifit. As tj90 said, if it doesn't communicate short them out. If it then communicates you know why. Check the required current spec for the part. 20mA or less which implies only the voltage drop is high, I wouldn't rush out and buy different LED's.

If you looked at Newark One you would find many choices. From my experience 1.4V is the normal bare LED.

Ray

tj90

Dang it - got the board assembled and realized that my OBD-II cables that I already had in my garage will not work with the board.... It turns out that pin 3 (K' Motronic) of the OBD connector does not wire out to the DB9 plug. I opened up the OBDII preabbed cable to see if the pin 3 wire was connected to the plug and it not. I guess I will need to buy another cable and OBD plug that has pin 3 connected.... More delays!

To the others ordering the OBD plugs - make sure that pin 3 is connected. You will need this for K'. I think the OBD-II standard does not use it and therefore will not work with the OBD-I 993..... I saw this:

http://www.obd2cables.com/products/p...products_id=35

Im thinking that this cable or just a plug will be required to get this interface to work.

Edward

I hope I didn't miss anything, but are the complete units done yet (Chris?? ), or are we still discussing the PCB+parts orders?

BTW, this is an enormous thread ...anything we can do to separate the discussions? Say, one thread for assembly/troubleshooting and another for complete units? Just a suggestion
Thanks for all the work, guys!!


Edward

maurice97C2S

Damn, I wish I'd spotted that, I ordered the connector without cable .. looks like it would be easier !

I had a cable which I had wrongly ordered from OBD-2 with their software - only five pins connected OBD end - 4, 5, 7, 15, 16 ...

Has anyone thought about picking up the knock detection on OBD pin 11 ? I can't find a reference to the signals used ...

cheers, Maurice

raycm

Maurice,

You can move the pin 4 wire to pin 3. Pin 4 is chassis which we don't need.

What does the knock detection signal on pin 11 look like? Data, analog?

Ray

Thaddeus

Hey, I'm slowly putting my board together and I have 2 questions I was hoping somebody could answer:

(1) The switches I got have 3 prongs coming out the back. They are each supposed to be connected to the three solder holes on the board via wire. Do I just attach middle prong to middle hole, side prongs to side holes, or is there some other order they must be attached in?

(2) What do the switches do? I assume they allow you to check different subsystems or something? Is there a 'key' that tells you which subsystem you are looking at when the switches are in any of the 4 possible combinations (2 switches times 2 positions)? Or will this become apparent when I have this puppy all together?

I am not an electronics guy. So far I've managed to attach the resistors, transistors, and diodes. I'm actually quite pleased with myself.

cowtown

1) Yep, connect the switch pins in the same order as on the board (this was one of the recent board revisions).

2) One switches between K and "K-Prime" lines, and the other switches between Motronic and other function groups. Easiest to write your own key down when you get it running - it only takes a few seconds to see which Scantool functions connect with which settings. Or you can look at the schematic to see which ODB lines are routed where with the different settings.

Thaddeus

Do we connect while the car is running, car is off but key 'on', or car off and key off?

Thanks for your patience, I am a nincompoop when it comes to these things (and several others ).

Don Plumley

Key on, but press the alarm button on the key fob to defeat the immobilizer.

JasonAndreas

In most cases you are better off connecting with the engine already running.

brucec59

Just realized my laptop doesn't have a serial port. Can I use a standard Serial-USB converter?

Lorenfb

"What does the knock detection signal on pin 11 look like? Data, analog?"

That output is a data output which provides a knock count per 10K cylinder ignitions.
At 3000 RPMs, it takes about a minute to do the sampling, i.e:

Time = 10,000 / (3,000 RPMs X 3 (fires/rev) ~= 1 min.

On the PST2, it provides a progression indication (moving bar) and the number of knocks
at the end of the sample period. Usefiul data only results under heavy load,
high temperatures, & with a standard/normal octane being used. The Hammer
provides a similar output.