Can't adjust timing...

[Lunch2000]

After going round and round with my 89 turbo, I finally got a timing light this week and checked the ignition timing. I have been having problems with high fuel consumption and smelly exhaust and my suspicions were confirmed when I found that the timing had been advanced off the scale of timing marks. My guess is that it is advanced between somwhere between 15-20 degrees BDC. My problem is this, I can't move the cam position sensor far enough to get it to where it should be, I believe factory is 12 and I can only get it just on the scale before it hits the lockdown bolt. Do I need to replace the cam sensor or can I open it up and adjust it somehow to compensate. I would also add that the compression on the engine is higher than spec as well, about 180 as opposed to 140, so if anything I would guess I want it a little below 12. I checked the TSRM and my Hanyes manual but can't seem to find anything. Any advice from the Supra Ninja masters out there?

Lunch