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EJ20 Select Monitor logging

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ratbug aka toddy101

439 posts · joined Jan 2003 ·

#705095
Well, last week i've been toying with the idea of hooking up the subaru engine computer to some sort of laptop-datalogger. Did a bit of net searching and found a few programs and tools. 1st up I tried the B10 datascan, which hooks up the select monitor port on the ECU and uses the old parallel port of a PC. It's meant for US cars, hence why it didnt seem to work on my JAP one.

I looked at the VWRX.COM select monitor software. It uses a serial COM port to communicate, only problem is the ECU uses TTL type logic, the computer has CMOS type logic, and they arn't compatible. I ordered a special USB to TTL serial converter, wired it up, but couldnt get it to read even the ROM ID in the ECU. Then further research found other people having no luck with the same USB-TTL coverter, others found it to work ok. Also modern USB-Serial converters are a no-go as well. You need to use a laptop with a hard wired RS232 serial port. Software support for USB devices is coming in the new version of the software.

So today went to jaycar, grabbed a handful of components and a prototype PCB board, put them all together, borrowed an oscilloscope from work to verify my circuit was working, hooked it up to the ECU, and bingo, i could read the ROM ID. The ROM ID wasn't recognised by the software, however doing a memory dump i quickly found that the addresses which were for an 95 wrx sti seemed to match up, so used it's lookup table... And the result.



This is the memory dump straight off the ECU.



Now if only the old laptop (my new laptop and most new laptops don't have rs232 ports) had a working battery I could drive around and do some logging, will have to get a laptop-car power adapter.

One thing I found interesting, the 1sr radiator fan didnt turn on until the ECU thought the temp was 96 deg. It then turned them off at 88. Havn't got the manual in front of me, but thought it was lower than this.
Sharbuilt Beach buggy with Subaru 2L Turbo
Thunderanch Riot with Subaru 2L Turbo
Manxter with FA20turbo
Click here for wiring looms

1303Steve Scirocco Rare

8,650 posts · joined Aug 2002 ·

#705111
Hi

Good work, this will give you hours of fun. So I'm guessing that you can only look but cant adjust anything.

Steve

Mick058 Custom Title Time!

1,580 posts · joined Jan 2008 ·

#705165
i'd be interested to know if there is a display screen thing you can get to plug in - i've got a stock 2002 STi ECU - is there something you can plug in that displays water temp, oil temp, oil pressure etc.
http://forums.aussieveedubbers.com/viewtopic.php?tid=67295 (myride)

Romans 10:9

Joel Now containing 100\% E-Wang

9,368 posts · joined Feb 2006 ·

#705170
mmm id love a touch screen setup like this



another point i throw at the pursists when they ask why go subaru 😂
music navigation and GPS is pretty cool to

ratbug aka toddy101

439 posts · joined Jan 2003 ·

#705175
Mick058 wrote:i'd be interested to know if there is a display screen thing you can get to plug in - i've got a stock 2002 STi ECU - is there something you can plug in that displays water temp, oil temp, oil pressure etc.
2002, your car should have OBDII which is a universal protocol used by just about all cars, theres a lot more tools available for them.

The subaru select monitor is subaru's own protocal, which is what they used on the earlier models before OBDII was standardised.

And yeah, you can look but not touch!
Sharbuilt Beach buggy with Subaru 2L Turbo
Thunderanch Riot with Subaru 2L Turbo
Manxter with FA20turbo
Click here for wiring looms

seagull Compulsive Aussie Vee Dubber

4,979 posts · joined Dec 2003 ·

#705182
Mick , is your motor / front cut a JDM or ADM ?

I hope its a JDM !
Looking for that special lady : PM me for coffee & cake