Sorry to everyone for taking this thread slightly off topic.
Hello James,
I have tried similar using the wps500 & intially did the same as you to try & identify a specific cylinder leak. I did find though that using the wps driving under load you could see a definite rise in coolant system pressure in line with engine load . This was on a TD5 landrover, which can be difficult to confirm a gasket leak on.
Regards, Andrew
ps Malcolm, it may be possible to see the abs sensor operation better by using a standard low amps clamp & getting several windings around the jaws, if the wire length allows.