Datalogs exported as CSV or TXT, can be viewed with MegaLogViewer. It can read those files, you can select the fields in the logs you want to see and even make (zoomed) screenshots if you want.
The paid-version will also do scatter plots which is a nice feature. You can also open multiple logfiles at once and view them as a combined scatter plot.
It's mostly used with MegaSquirt setups but the MegaLogViewer can be used with just about anything that exports text-based logfiles.
