OBD-1 Dash Display

General discussion forum about the 240sx, and a great place to introduce yourself to the board!
jacob005
Posts: 11
Joined: Wed Nov 06, 2019 2:50 pm
Car: R32 Skyline GTS-4

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Hi all,
I was wondering if anyone has found a solution to getting data from their OBD-I Nissan’s ECU? I don’t want to replace the whole computer with a standalone due to the cost and wiring. I want more data on my r32 skyline but don’t want to have a bunch of extra gauges on the dash and sensors wired in everywhere.

My current idea is to use an Arduino microcontroller to read data from the stock computer, through the OBD port and display it on a screen mounted on the dash somewhere. It could be configured to send signals to ECU just like the Nissan Consult devices. One could then see things like engine temp, voltage, injector pulsewidth, fuel economy, etc while driving. It could also read and clear error codes.

The really cool part is that it would be easy to control outputs like progressive water/methanol injection, boost control, or read an ethanol sensor for a flex fuel setup. The Nistune setup allows you to use ethanol as fuel but you have to convert the sensors frequency signal to a 0-5V signal.

Ultimately the idea is to create a cheaper system of displaying data from the car, in real time, to help with tuning and diagnosis.
I would love any feedback on how you all have solved this, thoughts on this idea, or if any threads already exist.

btw I posted this in the RB engine forum at first but thought I'd try here since this gets more traffic and the 240s use the same consult system


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IanS
Posts: 10090
Joined: Thu Dec 23, 2004 3:07 pm
Car: 2002 Subaru WRX, 2010 Subaru Forester XT, 2004 Infiniti G35 Coupe.
Location: Esko, MN
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It is possible. Its been done with a raspberry Pi, using a tablet as a display/interface.

I read into it a bit, but needed more functionality out of my system, so I went standalone before attempting to recreate it for my own car.

jacob005
Posts: 11
Joined: Wed Nov 06, 2019 2:50 pm
Car: R32 Skyline GTS-4

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https://drive.google.com/file/d/1-i2tGv ... sp=sharing

https://drive.google.com/file/d/1-iMRYF ... sp=sharing

Does that picture work? Im using a touchscreen thats made for data display to make it easier to program the gauges

Thanks for the feedback! Can you tell me more about what functionality you needed that made you go standalone? I figured that between a Nistune and this controlling boost or meth injection it would come pretty close to a standalone functionality

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IanS
Posts: 10090
Joined: Thu Dec 23, 2004 3:07 pm
Car: 2002 Subaru WRX, 2010 Subaru Forester XT, 2004 Infiniti G35 Coupe.
Location: Esko, MN
Contact:

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jacob005 wrote:
Tue Nov 19, 2019 3:07 pm
https://drive.google.com/file/d/1-i2tGv ... sp=sharing

https://drive.google.com/file/d/1-iMRYF ... sp=sharing

Does that picture work? Im using a touchscreen thats made for data display to make it easier to program the gauges

Thanks for the feedback! Can you tell me more about what functionality you needed that made you go standalone? I figured that between a Nistune and this controlling boost or meth injection it would come pretty close to a standalone functionality
Nistune was in its infancy when I made the change, and I was building a 12/1 compression KA with Individual throttle bodies so I needed the ability to not only tune but configure inputs/outputs.

jacob005
Posts: 11
Joined: Wed Nov 06, 2019 2:50 pm
Car: R32 Skyline GTS-4

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Oh nice that sounds fun!

Can you tell me more about what sorts of inputs and outputs you needed? Its easy to have the arduino read sensors or control solenoids, but you wouldnt be able to change the tune based on inputs.

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IanS
Posts: 10090
Joined: Thu Dec 23, 2004 3:07 pm
Car: 2002 Subaru WRX, 2010 Subaru Forester XT, 2004 Infiniti G35 Coupe.
Location: Esko, MN
Contact:

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jacob005 wrote:
Wed Nov 20, 2019 4:10 pm
Oh nice that sounds fun!

Can you tell me more about what sorts of inputs and outputs you needed? Its easy to have the arduino read sensors or control solenoids, but you wouldnt be able to change the tune based on inputs.
I needed the ECU to be able to read an aftermarket TPS, as well as control fueling based on speed density, not a MAFS. So I needed a MAP sensor, and an IAT sensor and the ability to scale the fuel and ignition tables via both inputs. I also wanted launch control, and the ability to force the engine into limp mode based on IAT, CTS, or Oil pressure inputs.


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