Sparkfun OBD-II Serial UART Board

ruan

New member
Hi Guys

Can anyone tell me if I will be able to access my ECU (to see what software is on it and maybe later on do so tweaks) on my 2006 impreza sti with this OBD-II Serial UART Board:

http://www.communica.co.za/catalog/Details/P1954322247

It looks like i'll need a extra board or something to connect to USB/computer, but I've only started looking into this.

I found a instructables guide which uses this OBD-II Serial UART Board to read codes of the ECU. This got me interested in doing something similar in my car.

http://www.instructables.com/id/Custom-OBD-II-Gauge-in-With-OEM-Look/

Any help/info would be appreciated.
 

HolyCrapItsFast

Drinks beer!
You will only be able to access general OBD2 data with that. If you want to access the subaru specific parameters you will need to access the SSM protocol and the only adapters that I know of that do that is the Tactrix or a VAGCom cable.

What exactly are you looking to do? Do you want to simply look at data or create a custom gauge? If it is as simple as looking at data then you can use RomRaider for that but If you want to create your own gauges then that is a different story. I do know people that did it but it was very complicated.

I have been looking into doing a custom gauge for monitoring OBD2 parameters but then decided to build a stand alone gauge. Then I setup a car PC and found a program called DashCommand to display OBD2 data in a gauge display. I also have other various displays and I use the Arduino to achieve them all

Check out my journal. I list it all there...

https://www.igotasti.com/vBforum/threads/8757-HolyCrapItsFast-Back-in-the-Suby-again!
 
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ruan

New member
Awesome thread/projects! I think my main objective is to create a custom gauge or 3... The main info i would like to display is: Air/Fuel ratio, water and oil temp, boost.

I was hoping to get all this info from the stock sensors on the car. Parts in South Africa are very expensive and my parts budget is also my beer budget.

My future plan is to install my car PC that I had in my previous car, but that was mainly just for entertainment.

My first thought was to use the OBD2 but after reading your thread I am now thinking it's a bad idea because I would like the gauges to work when the car is getting tuned.

Will I be able to connect into the oxygen and MAP sensor's wiring without confusing the ECU?

I don't know much about Arduino programming but I have access to people that can help me with that. I just need to decide on what I want to display the info.
 

HolyCrapItsFast

Drinks beer!
I highly recommend not tapping into any sensors. It can introduce noise and skew the reading. For the 06 sti the O2 sensor is not a true wide band and the ecu will not display the correct AFR at WOT. It also will not provide oil temperature. It seems as thought you would be better of making stand alone gauges Or just buy some standard gauges and be done. The only reason I did what I did was to put everything into one display for easy access to the info I am interested at the time. My boost gauge is also stand alone because it is far more accurate than the ECU and any other gauge you can buy because it is atmosphere and altitude compensated. All of the sensors are standalone and I bought them on Ebay for cheap.

I did all of my own programming and I am sure I could help you with a lot of it if you decide you want to go the custom route.

Also check out this link. This is my project thread on 4D Sysytems forum... http://forum.4dsystems.com.au/forum...-systems-as-an-automotive-multi-gauge-display
 
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ruan

New member
Ok, so the more I think about it, the more I'm leaning towards replacing the stock boost gauge on the steering column with a custom 4-in-1 gauge (AFR, Oil temp, boost and volts). The display will either be an OLED or TFT screen.

1. What sensor do I need for the Oil temp? you mentioned that you used a DS18B20 digital sensor. The DS18B20 sensor I can get here is not in a adapter with thread. Did you buy the sensor as a unit?

2. How do I know which wideband oxygen sensor to get?

3. Did you add a separate MAP sensor for the boost?
 

HolyCrapItsFast

Drinks beer!
I made the sensors. I simply drilled out some NPT adapters with a 6mm drill bit and epoxied them in. I used JB Weld for that.

There are several options for the wide band. For mine I installed an AEM wideband hidden in the glove box and the 0-5 volt output drives the display. Another option is to use the Spartan 2 controller from 14point7 here... http://www.14point7.com/products/spartan-lambda-controller-2 Both use the LSU 4.9 sensor.

For the map sensor I used MPXH6400A from Freescale and built it into the internal circuitry. Technically you can use any MAP sensor you like as long as it has a 0-5 volt output and is at least 3 bar.
 
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HolyCrapItsFast

Drinks beer!
Best place is right after the turbo before the bend in the down pipe. Second best place is just before the first catalytic converter.
 

Alin

Diehard Car Enthusiast!
1592D134-969F-4735-B9BF-9C4E3A7F778E_zpszbmtsimp.jpg


Here is where mine is! :tup:
 

HolyCrapItsFast

Drinks beer!
I use to recommend that location and it is still a good place because it gives smooth results. However it is not ideal for tuning purposes because the signal is delayed and you may not be adjusting for the actual AFR at the time. Since your MAF is very smooth it has little impact so what ever previous AFR was read still applies to the next cell in the MAF.
 
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