[Hotrodjohn71]

I recently purchased a Powermaster 7294 alternator for my 1967 Pontiac to convert it from the old 10dn setup.

Let me preface with the detail that my distributor (HEI stock style) is powered by a 12v relay which relays battery power to the HEI and is triggered by a 'key-on' power wire.

My problem is that the engine wont shut off when I turn off the key. The charging is good.

Wanting to keep use of my 'ALT' dummy light in the dash, I connected the Powermaster plug '1" wire to connect to the brown wire that goes to my ALT dash ight. The Powermaster 7294 is designed to accommodate the dummy light option.

Also, by way of the adaptor plug I have that attaches where my old regulator was, the '2' wire on the Powermaster is connected to a wire going to my main positive 12v splice.

This seems to be correct from what I have researched.

I did notice that if I disconnect the adaptor plug where my old regulator used to be (which disconnects 1 from the ALT light, and also disconnects 2 from batt + 12v, then it will shut off with the key.

Is a diode necessary? Will it still allow the ALT light to function?

Can you shine any light as to why the engine wont shut off with the key switch?

[stellar]

The diode is necessary. The light will still work. Feedback from the alternator to your ign.

[Hotrodjohn71]

Just for a bit more description, here's one of my work-up notes. I followed this diagram.

[hobbygto65]

If you use a 10si alternator.number 4 and F should go together and 2 and 3 together.

[george kujanski]

Add a 1A. or larger diode in series with the #1 terminal wire, with the arrow (or "banded") end towards the alternator. The functionality is: with the key on, engine not running, current from the idiot lite goes thru the diode to the alt to 'energize it once it starts spinning. The lit lights up. without the diode the #1 terminal outputs about 14 volts which feeds back to the ignition circuit to keep it alive. The diode prevents the feedback but allows the lite to work.

George