I am sure vss cant be anywhere on the engine itself. It has has to be somewhere after the drive train. Anyway I dont think vss signal has anything significant to do with the ignition timing if any. As i havnt seen it, could u pls tell what type of ignition setup spectra uses. I mean if its dual coil waste spark type like in baleno or plug mounted independent type like in vti and corolla or conventional rotor distributer type. A couple of good photos of engine compartment will help.
Fli_Gti
I think he unable to get his ignition advanced enough even using an advancer.
personnaly I think its could be incorrect type of TAP and/or wrong installation.
Recently i came accross a baleno installed with a TAP ment for single coil ignition system. The TAP was only advancing one out of two coils and that too in wrong because it was getting one spark pulse instaed of two every 360 degree of crank rotation. So all its calculations were wrong. So be careful of the mechenics who cant even read in english let alone the complex installation instructions.
Sorry for making it even complicated an issue.
regard