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Old 12-14-2006, 05:07 AM
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bwilson4web bwilson4web is online now
Engineering first
 
Real Name: Bob
Location: Huntsville, AL
Hybrids: Prius Classic 03
Posts: 4,934
Thumbs up Re: Just days away from my new Vue!

Sounds like a good plan.
Quote:
Originally Posted by Xyrus View Post
I've considering getting a scangauge II, however I'm a little tapped out due to the holidays.

It seems there may be enough information on line to write a serial port interface (using a USB adapter) through the OBD port. I think I remember seeing the spec online somewhere so it should be possible to write a small program that would allow a computer to hook up to it and record whatever data one was interested in. If a cable doesn't already exist for serial to OBD, I'm sure wiring one up wouldn't be that difficult.

Though what I am most interested in is a dump of the firmware. I want to know whether the firmware in the ECU was tuned for best EPA test performance or was it tuned to more realistic driving condintions. I'd also need to know what CPU the ECU is running with.

Unless there is a seperate board controlling the battery/electric engine throughput, then I should also be able to see if it is possible to tweak the firmware to allow additional batteries or maybe a slightly more powerful electric engine. Not going to get my hopes to high on that one though.
Initially, I put my own instrumentation taps in and still do for time critical data. I now have a scanner and it is good new, bad news. The good news is it reports summary data from the control computers but the bad news is this data is sometimes not very real-time. Worse, the OBD interface changed with the new model year and folks are still struggling with 'reverse engineering' the interface.

The best results are coming from those who put in their own instrumentation. They don't have to worry about deciphering interfaces that the manufacturer doesn't seem all that thrilled about sharing. Send me a PM if you decide to try this approach and I'll be happy to share 'lesson's learned' about:

1) running Cat-5 as a data cable from engine compartment to cabin
2) using stereo audio line input for recording data
3) use of magnetic pickups to non-invasive pickup signals
4) a nice $20 TI microprocessor kit

GOOD LUCK!

Bob Wilson

.

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My
other 1500 cc car:

Automatic, stock, backup car.
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