Hondata

I was data-logging on-board (USB not connected) for 20+ minutes with P72 S300 V2.

The internal memory was 50% used

After downloading the data log, the data log, though viewable had lots of jagged lines on any sensor trace.

Also the ECU would not accept an calibration upload.

When I downloaded the calibration in the ECU, it was the stock P72 calibration (instead of my duno tuned calibration)!

What are the potential causes for this that should be looked into?

I have done shorter on-board data logs with no issue

I have installed the Analog wiring connector (on top of the heat sink) as per the help file picture

if the tuner didn't upload the tune to the s300 tab/button the one to the left of the Tables button which is next to the parameters button on the top tool bar, then you'll have to get him to email you the copy. the S200 ecu's just overwrite to the main board where as the s300's you can chose when to upload the config which I find more handy so that If I screw up I could always pull the file off the ecu's memory kind of like an internal USB drive where it stores the calibration file, and doesn't have to pull the calibration from where the ECU reads the calibration, they probably did this for consistently good downloads, and that's probably why you always have to read the disclaimer about making sure the tune is the proper one after downloading.

as for not being able to upload, you sure you have the USB drivers installed correctly? and the tuner didn't set a password for uploading.

From Help, About, what version of software are you using?