I'm trying to see how many fuel injectors a NA RX-7. I've only been able to find two, but I've looked through the forum, and see that others have four for the 1990 version. I also want to know where the 2nd set of fuel injectors are. Thank You!

 

Four. There are the two secondaries (which are the ones you can see easily with the manifold on) and the two primaries (which are buried under the manifold).

If you look in this section in the intake rebuild thread, there are photos provided. It's for Series 4 (1986-1988) models, but it's largely the same.

 

As wondrous bread said, there are 4.


Only thing to add is:
If you're planning on replacing them make sure you're using the correct injectors. 1990 was high impedance, and the plug was different than the S4's. Make sure you get S5 injectors as they are different.

If you're just wondering where they are, there's a great writeup by the man, wondrous bread, himself in the sticky section of this forum. That'll have all the info you need