Hi Debbie and thanks for the data you sent, sorry I have not responded sooner.
Looking at the data it is very strange to see that every alternate cylinder reports low efficiency which indicates one bank of cylinders, given this vehicle is equipped with a flat plane crankshaft.
If you “right click” on the psdata file you can see the signal waveform which also supports the finding of the bar graph that alternate peaks do tend to fall after higher peaks. One thing to remember is the bar graph is an average of the waveform signal for a “at a glance cylinder performance indicator” and all values are approximate. It was interesting to see the compression values did increase by 10% on cylinders B, D and H with the throttle wide open, confirming airflow is everything with a compression test. However cylinder F remained lowest at 47% and this would be my cylinder of concern. I would really love to know how the airflow is distributed throughout the intake manifold and could this have had an effect on our result, or moving onto the exhaust flow rate via the offending bank exhaust manifold?
How we interpret the bar graph results is also important and that is, Cylinder F demonstrated reduced current consumption when under test in comparison to cylinder A, and not necessarily has a lower compression to the value of approximately 50%
Factors other than airflow that come into play when measuring compression via current draw are the influence of the flywheel, inertia dampers, variable valve timing, multi cylinder engines, (8 and above), internal friction, and electrical circuit resistance ( including battery type)
We must remain mindful of all the above when carrying out these tests and confirm the results in the correct manner as you did with additional tests once potential errors have been found. (Nothing wrong there)
As a “first look” approach the Pico diagnostic compression test is a really valuable tool, but to base a major engine repair on a single” first look” test alone would be ambitious, in the same way as measuring low voltage across a battery with the engine running and condemning the alternator with no additional tests.
Hopefully Debbie if you do manage to get this vehicle back and if you have the time it would be great to carry out some additional tests to help us all understand and explain all these variables, can you send the vehicle over to me in the UK?
I can but hope, take care……Steve