Electronic Spark Advance stopped working

[Ineptitude01]

I convinced my poor dad that more Z's is always a good thing, so we've been fixing up an 83 Turbo. He was driving it around town, getting a new muffler welded on, etc etc. when he killed the car (slave cylinder seeps; slowly came into gear) in the parking lot of the exhaust shop and couldn't get it started again. It would crank, but not catch.

 

We brought it home and since there was no spark from the coil, decided that the thing that must be happening is that the CAS stopped working. Replaced his distributor with my known good one from my build, car fired up on the first try.

 

We then started trying to time the engine, and just when I was homing in on 24˚BTDC, the timing mark disappeared and the tone of the engine changed. I figured "Oh great, I must have advanced it way too far."

 

Turns out I couldn't find it because the mark was at TDC, and now will not advance properly. It sort of wiggles around a bit, maybe 3˚ in either direction, but definitely isn't advancing. The car runs and drives well enough, and the turbo spools, but it's just... gutless, and awful.

 

Is there any common problem that would account for this?

 

Other information:

 

Plug wires are OLD. Old enough that they've gone from black to gray. I keep telling my dad that he needs to replace them, but he's convinced they're fine.

Plugs are new and clean.

The four pin EFI connector is connected well, and making contact on all pins.

The black wire with the spade lug is similarly well connected.

The distributor is turned 'full advance', and the motor sputters and dies if you turn it back.

We've ordered a reman'd dizzy, but I'm not convinced that will fix whatever's wrong with this.