Strange starting problem

[Tenchuu]

after searching i decided that this is likenothing that anyone else has posted.

I have a S14, and the starter started to make a metal "pinging" sound whenever it started. so i go and replace the starter. pinging sound stopped, but starter still had problems. one week goes by, that used starter's nose come busts in 1/2 so i buy a re-furg from the parts store. now this one is good for about 3 days, then istart having to get a jump to dtart in the mornings. also sometimes i would turn the key and nothing would happen. othe times it would click once and then nothing. Next i get my 3 month old optima battery tested and sure as shit it is low. battery gets a fresh cange ans load tests good now. now it starts but the same things happen. turn the key and nothing, turn the key and one click then nothing. a week goes by and i am dealing with this.
then things change.
now the starter just makes a whirring noise, like it is turning, but not engageing. thing is the key is out, and all, i tried removing fuses, but nothing makes it stop besides disconnecting the battery. now heere is the difference between my car and stock, i have the battaer in the back, so the cable runs directle from the battery to the starter then up to the under hood fuse box.

any ideas to help? i check the ignition cylender, tried to move it, it is a little loose, but none of my accessories work, so i don't think it is stuck inthe on position. i also looked for a starter relay, diddn't find one and parts stores diddn't find one in thier system. altoh there is clearly a relay in the FSM starting diagram. thinking that maby the relay is stuck in the start position, but why would it not start if that's the case? think maby the re-man starter went bad? maby the selinoid isn't engageing and it is stuck spinning without moveing out and lineing up with the teeth in the engine? anyways i am on foot until i can get some help so please help out!