Howdy,
Like VC said, how did you set the timing?
With our cars (S14 and S13 I think) you need to remember wasted spark, ie the spark plugs fire in batches of 2, Cyl 1 and 3 fire at the same time and 2 and 4 at the same time, all that happens is when Cyl 1 is at combustion then Cyl 3 is sparking an exhaust gas mixture. I dunno why they do that... any ways if you use a timing light that you can set the degrees on with the wheel at the back you need to double the degrees, if you're looking for 15 degrees, you set the light to 30 etc etc.
If you use the conventional light where you aim at a timing mark then I dont think you have this problem the light just "seems" dimmer as its flashing once at the timing mark and once 180degreed the other side of the mark.
I hope this all makes sense!
FYI, my timing is at 12.5 degrees AFAIK