voltmeter is bouncing
 

i searched but i couldnt find anything conclusive. i just swapped back to my stock alt today, with the single pulley, and it creates alot better volts, especially at idle. but tonight on my way home with the lights on i noticed it was a tad less, and when i would apply the brakes, or the turn signals it would fall slightly, and it would bounce with the turn signal.

to me it seems like a bad ground or a bad connection somewhere but everything was fine today, all i did was disconnect the batter and the alternator, then reassembled everything. so i dont know why anything else would be different, unless this is a sign of a bad alternator. then idk.

sounds like a bad ground. i would start by cleaning all of the grounds in the engine bay. the ground on the left strut tower is a common failure point. finally, re-check belt tension. Aarokcake has a great write up for the FC guys here:

http://www.aaroncake.net/RX-7/grounding.htm

though it does not apply to the SA or FB, its still an excellent write up.

This should help somewhat:

https://www.rx7club.com/showthread.p...=carter+holley

Start at post 35 :)

I have this exact same problem, and moreso I definitely agree it is NOT the alt. Mine has been this way for at least 3 years and I have changed/upgraded grounds, cleaned a bunch of stuff and finally just gave up. I also added a ground from the alt tension bolt to the neg on the batt. I am thinking I will just use relays for headlights, and fuel pump. Hopefully this makes the symptoms better, although I know its best to just fix the cause, except I cant figure out what exactly the cause is.

I am thinking Dave just needs to come to my house and fix this stuff for me... Sure would be easier lol.

haha, i actually found this when i was searching, but i couldnt figure out if you were suggesting to re-wire the fuel pump to fix it?

most of the common voltmeter bouncing seems to occur in 81-83 cars. i had a similar problem in an 81 GSL that i had years ago. replacing the negative cable helped. i also cleaned all of the engine bay grounds. taking the grounding point down to bare metal is crucial. often times you can see the fuel pump pulses through the voltmeter. a very annoying thing to look at if you ask me.