Is it possible to split the OBD2 data??

[Redline Motorsports]

We just got our new dyno last week and it the capability to log OBD2 data. It's actually pretty cool logging spark advance over torque!

Only issue is that doesn't allow me to log with EFI Live as the ALDL is know used. I am trying to figure out if I can somehow split the data signal so both the dyno and Live can read data. Does anyone know if this can be done?

I thought I wasn't going to be able to split my WB output between the dyno and Live and it works like a champ. Don't know if the PCM data is different.

Anyone have any thoughts?

Thanks

Howard

[Redline Motorsports]

ooooooooooohhhh!! Just found this!

http://www.carplugs.com/Product_view_Cables_2.html

[MMLMM]

ooooooooooohhhh!! Just found this!

http://www.carplugs.com/Product_view_Cables_2.html

Im pretty sure it dont work like that. First request gets the data, second one doesnt get the right data. iirc that was a test pat did on a Dmax

[Blacky]

Link to a similar problem, saves me typing out the reply again.
http://forum.efilive.com/showthread.php?t=8322

Regards
Paul

[Beerman]

I've used a Y cable with an ELM 327 chipped interface. Using hyper terminal and the "MA" Monitor All command I was able to see scan tool messages. But I don't think you can send a bidi message while requesting data unless you figure out a way to time the messages so they did not interrupt one another.

[Blacky]

I've used a Y cable with an ELM 327 chipped interface. Using hyper terminal and the "MA" Monitor All command I was able to see scan tool messages. But I don't think you can send a bidi message while requesting data unless you figure out a way to time the messages so they did not interrupt one another.

Messages interrupting one another is not a problem with VPW and CAN protocols. The hardware takes care of message contention using prioritized, non-destructive, arbitrated, collision detection and most hardware implementations will retry sending a message that is bumped by a higher priority message. (Message collision is a problem that needs considering with the old OBD-I ALDL protocol.)

The problem is that the scan tool (i.e. FlashScan) programs the controller to send back a certain set of PIDs at regular intervals. Any other scan tool or device on the OBDII bus will not know what those PIDs are and will not be able to interpret the PID data being transmitted by the controller.

If a scan tool is simply working with the generic OBDII commands, requesting single PID data, then other tools should be able to issue commands as well. Although that will cause problems if both tools are using the same ID (which is likely*). Neither tool will be able to distinguish replies sent to it or the other tool.

*FlashScan uses the same ID as GM's Tech2. Originally we didn't, but programmers for some aftermarket equipment appear to have hard-coded their devices to send/recv messages ONLY using the ID that the Tech2 uses. That means we have to use the TechII's ID to send/receive replies to/from those devices. Which also means most other devices will probably do the same.

In other words it probably won't work, but given the right set of (unlikely) conditions it may work.

Regards
Paul

[mr.prick]

:offtopic:
looks like you found a replacement V2 to OBD2 cable
for anyone that has lost or damaged theirs.
http://www.carplugs.com/Product_view_Cables_12.html

[Blacky]

:offtopic:
looks like you found a replacement V2 to OBD2 cable
for anyone that has lost or damaged theirs.
http://www.carplugs.com/Product_view_Cables_12.html

Interesting, I never knew any other scan tool used an RJ45 connector. If it is the same pin-out then it should work fine. The pinouts for FlashScan are described in this doc:
http://download2.efilive.com/Tutorials/PDF/Bench%20Harness%20Tutorial.pdf

Regards
Paul

[mr.prick]

Interesting, I never knew any other scan tool used an RJ45 connector. If it is the same pin-out then it should work fine. The pinouts for FlashScan are described in this doc:
http://download2.efilive.com/Tutorials/PDF/Bench%20Harness%20Tutorial.pdf

Regards
Paul

out of curiosity,
why isn`t a spare cable available here?
http://www.efilive.com/c-4-Spare-Parts.aspx

[Blacky]

out of curiosity,
why isn`t a spare cable available here?
http://www.efilive.com/c-4-Spare-Parts.aspx

It should be, the new store will have it as a spare part.
I think we've only had about 3 requests for a replacement cable.

Regards
Paul