Here's what I know...

My model has a super complicated system of shutoffs (EGR?) and stuff, and no bowden cable. I've bypassed everything I could and am trying to isolate the shifting issue...

If I remove all vacuum connections from the modulator (no vacuum to modulator) it shifts late everywhere after 2nd gear. In other words, from 2-3 and 3-4 I have to reach a high speed before it shifts, revving up a lot.

If I attach the brake booster directly to the modulator, bypassing everything else (maximum vacuum to the modulator) it shifts early. This time, it's always slipping and doesn't want to stay in a gear if I floor it... it only wants to go reaaal slow.

If I attach the brake booster to the VCV to the modulator I get this reading:
https://goo.gl/photos/QHS1rU6Bjn1dkNaV9
It looks regular, right? But now it shifts late again.. like having not enough vacuum. Should I mess with the VCV to get it bleeding more/less? Should I play with the modulator? Both the VCV and modulator seem to leak slowly albeit consistently if I plug them into the mityvac..

I know, I've read that modulator shouldn't affect timing, but it does. So
there's something I'm missing... Depending on how much vacuum is going to the modulator, it shifts at different times with respect to speed and/or throttle. Are the vacuum numbers so far off that it's just mayhem, or is the problem elsewhere?


Any tips before I do more harm than good?