Now dont take this the wrong way but thats not quite accurate. Me and Russel had a tough time wrapping our minds around this! But basically, you cant do a map kpa to inhg conversion and have it end up right! Its essentially opposite! I fought myself on it for quite some time! An easy way to see the "wrongness" is to go here,
http://convert-to.com/195/pressure-units.html
Select kpa to inhg. type in 30kpa. Great idle vacuum right? probably around 22inhg? NOPE! its about 9inhg! Now type in 70kpa, full on huge cam maybe 10ingh tops! NOPE! its about 20.5inhg! Like i said, it warped my mind for quite some time. Basically, the further the map sensor is form 100kpa(atmospheric pressure), the more vacuum the engine is producing. In a few of my videos i have a vacuum gauge hooked up and it shows the actual ingh which if i remember right was around 16? About your suggestion to run it with vacuum lines capped. Been there done that! I have done every combo under the sun of having EVERY vaccum line plugged, cap one off at a time, swap pcv valves, you name it i have done it as far as capping off vacuum lines with no change in vacuum readings.
About the timing, it is set physically with the tss wire disconected at about 6*. I havent changed anything in the program to reflect that. Another word towards timing, i have adjusted it every possible way you can imagine in what feels like 1* increments! Started at 0*. Bumped it up a couple. Couple more. Couple more. Couple more. Couple more. Until i had gotten it so high that it started running way bad. with no improvement in vacuum readings or running condition. I have also done just the opposite to the retarded side just for fun. Retard 2*. Couple more. Couple more. couple more. Until it was about ready to die. With no improvement in vacuum readings or running condition. I have been fighting the idle on this thing for damn near 5 years. You name it, i have done it or replaced it. Short of dicking around with the cam and up until now, the computer. Even with that being the case im always open to any possible suggestion anyone can think of just cause "who knows?".