Write up on HOW-TO ground your laptop/USB controller/etc?

enjoyrth · Post by **enjoyrth** » Thu Jul 30, 2009 11:19 am

I don't know about everyone else on here, but I am really getting sick of not being able to datalog anything anymore. When I am in the car by myself, and can't constantly reconnect, it is impossible to do any sort of data logging or even realtime editing, which is supposed to be the beauty of nistune. I have read that we need to ground all sorts of things to make nistune work how it is supposed to work, but I am not sure how to do this. Do you think it would be too much to ask for a specific write up, maybe even with pictures, on how to do this?

Matt · Post by **Matt** » Thu Jul 30, 2009 1:16 pm

what vehicle are you using?

sure we can put a grounding etc document together ... probably part of the diagonsis document

enjoyrth · Post by **enjoyrth** » Fri Jul 31, 2009 7:59 am

i have a 88 300zx, using an 86 300zx ECU

Matt · Post by **Matt** » Fri Jul 31, 2009 11:55 am

added to my list. I'll put something together soon

enjoyrth · Post by **enjoyrth** » Sat Aug 01, 2009 5:30 am

Think I could get some guidance in the meantime? My ECU is grounded for sure. Other than that, there is the cable coming from the ECU to the laptop and my laptop. How should I go about grounding these things? I am also using a serial to USB adapter for my zeitronix wideband. I never have problems with that disconnecting and it doesn't seem to matter whether that is plugged in or not, as far as the nistune disconnect problem goes.

Matt · Post by **Matt** » Sat Aug 01, 2009 2:22 pm

Basically electrical noise from the vehicle gets into the USB cable and so much noise occurs that it disconnects the laptop

We have followed the design rules for USB with appropriate filtering etc so on a hardware side not much more we can do. Its the noise getting into your laptop from the ECU causing the disconnects

Electrical noise is generated by the ignition system and also injectors

It feeds back through the signal lines back to the ECU

However the ignition system is grounded via the plugs to the engine and the injectors to the ECU

Sufficient grounding of engine to chasis, chasis to battery and ECU to chasis are required

Check all grounding points are clean and secure for these items

Check the capacitors in your loom in the engine bay are clean and secure as these absorb the spark signal

Make sure ECU is installed to chasis and if still having problems with the laptop, try running from battery only and then also try grounding USB point going into laptop (ie shield) to an earthing point such as cigarette lighter ground

A properly grounded vehicle will not disconnect. I found during my testing that particular laptops were prone. My newer dell inspiron and vostro laptops never miss a beat on my Type 1 RB30

but with my last car the older dell latitude would suffer the issue you saw until I grounded the ECU and laptop itself to the chasis to abosrb the noise going into the chasis

Firehawk · Post by **Firehawk** » Sat Aug 01, 2009 3:00 pm

In all the vehicles (all z31) that I have tuned, not a one had a problem with disconnects. I have had other issues, and that seemed to stim from the laptop getting older, and replacing it with a newer one was the solution. Sadly, laptops don't seem to last nearly long enough. Escpecially the battery.

Matt · Post by **Matt** » Tue Aug 04, 2009 6:52 pm

im on my third battery with the inspiron, but this thing gets used for hours daily

Matt · Post by **Matt** » Thu Aug 06, 2009 10:07 am

i've updated the installation/diagnostics document with this info this morning