Yep, for some reason my tach works, I just ordered a tach adaptor for my 93 240sx and since it's gonna be here friday, I thought why not, I can do 2 days without a tach so I installed it. To my surprise, my tach works just fine!?! Confused I took a look at the MSD incase I wired it up wrong but it seems right to me, wires are going into the ignition box then to the SS coil pack then to the distributor bypassing the stock coil pack completely... So why is it that everyone else needs a tach adapter??? Thanks for putting up with my questions everyone.

You have a DOHC, right? I needed it on my SOHC. I honestly dont know how the DOHC differs from the SOHC when it comes to the ignition coil. I installed my 6AL becuase it said some applications may need the adaptor. Of course, mine did. I had to cut the wiring harness off of the stock coil pack and those 2 wires (black/red and green/black) go to the black and red off the ignition box. Then the orange and white wires go to the Blaster coil. This turned my factory tach off, so i had to purchase the tach adaptor in order for it to work. The white and red wires off of it joined with the white and red off the ignition box to turn the tach back on. Im sorry if this wasnt the case for you. Again, im not sure what the difference is between the coil pack on a 90 and a 93. Hopefully, if u dont need it, you can still return it. Again, sorry! :slap

Hey, thanks for the info on the 90, When the tach adapter gets here, I'll install it to see if there's any difference.

the DOHC tach runs off a 16v system, whereas the SOHC tach doesn't, you don't need the tach adaptor in a DOHC for that reason. : ) Its the same reason you need a DOHC tach to read the signal from a SR20 motor when you swap into a SOHC, its a 16v signal.

I see... so that's how it is. Well, I got a Tach Adapter here, might just keep it around just for the heck of it. Thanks Daunt... that sure got rid of any doubts I had about my setup.