I was looking to buy a speedhut tachometer and where is the ignition coil, I need to connect the yellow wire to the negative of the ignition coil pack. i have no idea where this is and if someone knows can you please send me photos or details to where this is, thank you!

 

Hello. Welcome to the forum. You might want to start by telling us what year your car is...there's 20ish years of RX7 on this forum, and we can't guess which one yours is.

Also, there are factory service manuals available for download for free online, which can provide you with anything you need to know such as engine and wiring diagrams.

Teach a man to fish...