My LCD screen project, boost, WBO2, Knock, etc

[Unlogic]

The chip in my post above is not the main CPU it's the chip used for serial communication. You shouldn't have to mess with that unless your having problems connecting to the serial expansion port.

[NickS VR4]

The chip in my post above is not the main CPU it's the chip used for serial communication. You shouldn't have to mess with that unless your having problems connecting to the serial expansion port.

Thank you. I will know in probably a year when I finally start working on my car again. Definitely going to be using the serial port to datalog with my android carpc setup.

[fastbikes76]

So a brief update,

I was on a drive all day yesterday and noticed the LCDBC would work fine if car was driven normally and on part throttle. It would stay connected for an hour or more if driven normal , as soon as I start doing any WOT runs though it disconnected straight away.

So I think we on the right track with noise suppressors

[Unlogic]

Did you encounter any slowdowns during normal/part throttle driving? I encountered it several times yesterday even with the filter in-place.

[fastbikes76]

Did you encounter any slowdowns during normal/part throttle driving? I encountered it several times yesterday even with the filter in-place.

I didn't initially but I do have to have my screen refresh set too #2 . Later on in the day after several hours of thrashing I experienced corrupt info where the coolant and ait readings were swapped around, as well as random stuff showing as constant disconnects regardless of driving style.

[BlackStealth]

So a brief update,

I was on a drive all day yesterday and noticed the LCDBC would work fine if car was driven normally and on part throttle. It would stay connected for an hour or more if driven normal , as soon as I start doing any WOT runs though it disconnected straight away.

So I think we on the right track with noise suppressors

My guess is when the fuel pump works harder, it draws more amps to maintain fuel pressure (or in the case of boost, additional fuel pressure) and this introduces unwelcome electrical noise. A weak ground connection introduces "ground loops" when there is large current passing through it.

Maybe this can be fixed by running an additional ground wire to the fuel pump?

I am currently drawing up an optically-isolated OBD2/MUT adapter -- this means a "ground loop" won't have any effect on it.

[Unlogic]

Optically-isolated sounds great.

Do you think the additional ground wire is needed even on stock cars?

My car has a bone stock fuel system and no hot-wire so it shouldn't have more electrical noise present than any other stock 3S.

[BlackStealth]

Most 94+ vehicles work fine with MUT, but there's a few cars that lose connection when the car is driven harder. Some have fixed their problems by cleaning up their ground connections (ie. removing paint underneath the bolt for better conductivity).

fastbike76 mentioned to me that he can maintain his connection using a notebook & USB OBD2/MUT cable. Since the notebook is powered by batteries ( a different power source ), it won't have the problem of a "ground loop". I am also examining the electronics inside the USB OBD2/MUT cable to see if it does anything better.

[2fnloud]

Most 94+ vehicles work fine with MUT, but there's a few cars that lose connection when the car is driven harder. Some have fixed their problems by cleaning up their ground connections (ie. removing paint underneath the bolt for better conductivity).

fastbike76 mentioned to me that he can maintain his connection using a notebook & USB OBD2/MUT cable. Since the notebook is powered by batteries ( a different power source ), it won't have the problem of a "ground loop". I am also examining the electronics inside the USB OBD2/MUT cable to see if it does anything better.

This is great because I would be less than thrilled to have issues like this.

Also how about that SD Card logging expansion?

[fastbikes76]

Most 94+ vehicles work fine with MUT, but there's a few cars that lose connection when the car is driven harder. Some have fixed their problems by cleaning up their ground connections (ie. removing paint underneath the bolt for better conductivity).

fastbike76 mentioned to me that he can maintain his connection using a notebook & USB OBD2/MUT cable. Since the notebook is powered by batteries ( a different power source ), it won't have the problem of a "ground loop". I am also examining the electronics inside the USB OBD2/MUT cable to see if it does anything better.

All my grounds are like new..the car has only had a genuine 4 years road use and 66K on the clock now. All wiring is original and MINT. I have relocated the battery to the boot and have tried adding additional earths. What I will do though is run a jump lead from the earth of the battery directly to the ECU mounting legs too see if that makes any difference.

I have to be honest and say there are no changes to my car, spec or wiring to cause this issue as far as I can see. Evoscan works perfect direct through the OBD port ...from my very non electronic experience its as if the LCDBC is too 'sensitive' and the info scrambles on big hard WOT runs.