Modified harness/engine won't shut off

[IdahoKidd]

Helping a buddy with his 75 280. He's taken the efi off and put on the tripple webers, etc. He says the motor won't shut off with the key. I have read where it needs a diode installed but can't remember where it would go. Anyone onboard that can give us a hand tonight?

Thanks!

Leonard

edit: crane xr3000 fireball ignition

Edited January 6, 2011 by IdahoKidd

[Arne]

IIRC, the diode in a 280Z is built into the alternator. Should be no need for a separate diode on that car.

[IdahoKidd]

Man that was fast! Thanks for the memory trigger Arne. He has a gm alternator so that makes sense. Newly modified harness so no real clue exactly what he has going on. First time start tonight.

[Zed Head]

Actually, they used the external regulator up to 1977 (I did the ZX internal regulator alt swap on my 76).

I think the diode is need with the ammeter, which passes current, as opposed to the voltmeter, which doesn't. When did they go to voltmeters?

Either way, I found this link - http://www.zcarcreations.com/howto/voltreg.htm - which says it's the L wire, if you need it.

[geezer]

You can either use a diode on the field wire on the alternator or instead use the charge light/idiot light to prevent run on as a field feed. I looked for an example and found this from a past project. My crude diagram shows both the diode and charge light but only one or the other is neccesary.

[geezer]

I forgot to mention that for a GM alternator, either a "SI" or "CS" type, just substitute the Nissan "L" field connection in my diagram with GMs #1. Also just ignore the jumper bypassing the remote sense. I drew that diagram up for another member creating a bare bones electrical system.

Edited January 6, 2011 by geezer

[IdahoKidd]

Thanks for the response guys! I am boogered up and can't get out much so was helping over the phone. It appears the crane ignition was fed from a fuse that didn't go off with the key, and thus.........well, it doesn't go off with the key. When I know for sure, I'll pass on the info for closure.