If a pocket logger can pull the actual engine timing variable from the OBD-II connector......shouldn't the XEDE be able to pass that information along and stick it into a log somewhere?

 

What does OBD-II have to do with the Xede?

d

 

WOW.....

If this data can be extracted via OBD2 port.....then Xede should be able to extract it as well. Its just a matter of tapping into another wire on the harness.

 

What?

Do you know how OBD-II works? There's no wire with the signal. OBD-II could, in theory, be implemented with just two wires. It's a protocol, not a wiring standard.
They are several different physical interfaces to OBD-II actually.

d

 

OBD-II interacts with the ECU.....thats where the codes are stored and that is where the data is coming from. Xede communicates with the ECU and should be able to extract the same info.

 

OBD-II is an access protocol to internal ECM state. I suggest you read SAE J1979.

Actually, no it doesn't. The Xede intercepts signals meant for the ECU and alters them. It only works because the ECU doesn't know it's there. There is no 'communication' in any formal sense of the word. When you boil it down, the Xede is simply a signal processor.

On the other hand OBD-II is _precisely_ a communication mechanism, designed especially for engine data access. You seem to believe that there's a wire that will give you RPM, MAF, etc. There's not. When you want this data (PIDs), you send a request for a desired value and it gets sent back. Everything happens along the same leads. There is zero engine logic at the hardware layer.

EDIT: wow. we're way, way off topic here.

d

 

Guy....there is a wire for each of those things....and if you were to splice into them and feed them into XEDE it could output what we are looking for.

 

This has _nothing_ to do with OBD-II. The idea that you can make the Xede read anything that can be accessed with OBD-II is simply wrong.

d

 

So you think that the true timing is never sent to the ECU? Please!

 

I've already withdrawn from that debate. I'm talking about post #31. I feel that it's necessary to point out that the logic is wrong so when somebody finds this thread in 6 months they don't get wrong information. OBD-II is a very specific thing. That's all.



d

 

And I feel you are wrong.....OBDII is specific but all that data is also routed to the ECU.

 

But I'm not. The ECU has data that simply cannot be read by _just_ wire tapping. Examples include DTCs, freeze frame data, running time counters, ROM checksums, etc.

EDIT: all this data is accessable with OBD-II scantools, but there is no "wire" giving such information.

d

 

I guess we agree to disagree.....

Unsubscribed,
JJ

 

First and foremost: With regard to OBD-II, everything that donour is saying here is correct

Also, in the S-AFC wiring diagram that was posted earlier, none of the wires called out could give you the information you are looking for (ignition timing).


Since the Xede is intercepting/modifying the CAS signal, it can calculate RPM, but that is it. You cannot determine the ignition timing from the CAS signal alone.

In order for the Xede to be aware of *actual* ignition timing (and not just the CAS offsets that you entered in the Xede maps), the Xede would also need access to the ignition signal(s). The time between the CAS and the ignition signal(s) can be used to calculate actual ignition timing.

Can the Xede accept another input (or inputs) and get the necessary firmware and software upgrades to make this happen? I have no idea. Would it be worth it? Eh... maybe. As it stands, there are other ways to monitor ignition timing, so a project like this would likely be *very* "back burner" for the Vishnu/ChipTorque team, even *if* they were considering it.

 

The overall engine timing is critical to tuning. I know Vishnu probably wont take the time to make those values available but it would be a great piece of info to have.

Example.....

You add in race gas.....switch to your race gas map and make a pass.....logging timing. If your timing is maxed out without retard through the entire band you can add more timing. If you see some retard in specific RPM ranges you and remove a degree or from that area and still add timing in others.

Now, timing sometimes gets pulled due to intake temp and coolant temp so these would be handy to have available as well....but all this data is available within the ECU. How you tap into it.....that is a different story....personally I think a piggyback wasn't intended to perform this tasking. The best solution would be a complete ECU replacement using the OBD2 plug as the interface. Then you would be able to log all these values without hacking the harness and such. Instead of trick-F[]CKING the ecu the way the EXED does it would actually be a real to life change.

So the bottom line is.....spend the $100 and get a pocket-logger.