He said switch was replaced. The reason the ford solenoid works well is will work with as little as 6 volts through the old wires.

Ah, but who said it was done correctly? Also plugging the connector back in could have pushed out the pin holding the black/yellow wire. If it's a wiring issue, fix the wiring.

I'm going to replace the old crusty piece that fits onto the solenoid anyway and then dig into the ignition switch to check it out. I remember it could shift a little to one side or the other; perhaps I didn't get it centered properly or it's just a bad one.

Are they still available?

Ah, but who said it was done correctly? Also plugging the connector back in could have pushed out the pin holding the black/yellow wire. If it's a wiring issue, fix the wiring.

Yes, they are: http://www.amazon.com/gp/part-finder/slide-show/1973/Nissan/240Z/ref=au_pf_cr_16?ie=UTF8&carId=001&partsNode=15732461

I obviously missed where he had replaced the switch.

But to answer the last question, Yes, they have been known to be bad out of the box. Try to rotate the brown electrical bakelite from the gray metal and if there is some movement, and this is where it's very subjective, it is highly possible that the Ignition Lock and Tumbler mechanism will not allow enough rotation to make proper contact to the Starter Contact.

My main point in this is to try the SIMPLEST things first before undertaking a complete disassembly and overhaul.

E

I added an auxiliary light relay to my starter last night and it works great so far. I had changed most everthing else and still had the click, click,click on many start ups. After adding the relay I started the car many many times over a few hours and it worked each time.

I used xenons30.com info to do the work, simple and easy to do...