This mod will save lots of people lots of money. It is also a good basis for real ignition upgrades.

After 173,000 miles, my ignitor finally bit the dust. Not wanting to spend $224 for another one, or an equal amount for a feeble MSD, I wired in a $20 (Wells #DR-100) generic GM 4-pin HEI module instead.

In a nutshell:

The ECU's trigger output wire (BL/O) feeds the HEI's pin 'G'.
Ground the HEI's pin 'W'.
Ground the HEI's base.
HEI's pin 'B' taps into the +12V dizzy feed wire (BK/P).
HEI's pin 'C' taps into the coil's primary wire (Y/G).
Remove the internal strap connecting the old ignitor to the coil plug center terminal.

I mounted the HEI module on a bracket next to the LH headlamp.

If $20 is too steep, head to the wreckers and get a used module for a buck or two. Almost every GM car from the mid 70's to the mid 80's has one.

If you don't want the stock coil, it would be just as simple to use an external coil if you add the extra terminal to the cap for it. Lotsa places have hi-perf. HEI modules and HEI specific hi-perf. coils too.


http://store.summitracing.com/partd...art=ACC%2D35361
http://store.summitracing.com/partd...art=ACC%2D35367
http://store.summitracing.com/partd...art=PNX%2DD2000
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An external coil on a '94 like mine is pretty straightforward:

Besides the new coil, you'll need a new 1,000 ohm resistor to feed the tach because the Probe's old coil has this resistor built into it.

1) Do not plug in the 3 pin connector to the disty at all.
2) Pin #1 Black/Pink (power) will be new coil (+) and HEI "B".
3) Pin #2 Yellow/Green (IG-) will be HEI "C" and coil (-) and one side of the new 1,000 ohm resistor.
4) Pin #3 Yellow/Blue (tach output) will get the other side of the 1,000 ohm resistor.
5) Big connector pin 6 Blue/Orange goes to HEI "G" as before.

1,000 ohms is Brown-Black-Red, 1/2 watt will be fine. $.50 at Radio Shack.

The 3 pin connector (C170) is numbered 1-3-2. Not 1-2-3 as the incorrect All Data connector diagram shows. The correct order is:
1= circuit 2 Bk/P power
3= circuit 731 Y/Bl tach output
2= circuit 732 Y/G tach signal (ignition ground) or "IG-" on the DLC.

The faded wiring on my car makes it impossible to tell Y/Bl from Y/G. They both look like Y/G to me. You can be sure you have the right Y/G (IG-) wire by checking for continuity between pin #2 of the disty plug and the (IG-) pin of the DLC-its the same wire.

On to the '95:

You will need to do continuity checks to see where the three pins of the old ignitor go to. I suspect its electrically identical to the '94, just repackaged. If that's the case, then it will connect the same way. You don't have the strap to remove like the '94, but instead, you'll need to cut the corresponding pin on the ignitor. One ignitor pin will mimic the "G" function, one will mimic "B", and one will mimic "C" on the HEI diagram.

Or, screw the old coil and use an external one. Then you can forget about the ignitor all together. Just make sure the three pin C170 is the same configuration as the '94 is, and use the same Blue/Orange trigger wire on the big connector just like on the '94.