am I correct thinking your regular leak down tester (dual gauge on the right) only measures general pressure loss (regardless whether it's through rings or valves) but your gauge hanging off the bonnet connected to the crank case, helps you measure precisely what leaks through the pistons? I was thinking about running compression and leak down test on my 2.2 in peugeot boxer (puma engine). ever since I bought the van it's got this weird behaviour where it blows a lot of bluish smoke when cold and revved to 2.5k rpm. it just blows big amounts of smoke. when warm it stops. over the years I changed the injectors, the turbo, cleaned the intake, blocked the egr off, changed the timing. recently I took the inlet manifold off to see if inlet ports ale blocked but because I ran it for a couple of years with the egr blocked there's no carbon build up. the only weird thing I noticed is while all the ports are a little wet with the oil film one particular port was outstandingly wet. that makes me think, maybe that one particular valve is letting pressure back? my second thought is piston rings are already pretty worn so they seal up properly only after warming the engine up.
