Can the single wire used for the oil idiot light also be used to operate a pressure gauge? I mean instead of the light? Or is the two pole pressure sender a must have?

I have a 911 temp/pressure gauge I'd like to instal.

Anybody out there with a BTDT?

TIA,
Mike D.

Yes, the idiot light wire can be used to operate the gauge w/o the light. Indeed, I'm using the oil pressure idiot light on my 911 combo gauge as the low-fuel light, since I lost the fuel gauge when I pulled out the 914 combo gauge.

OK, so to operate the gauge all I will have to do is add a ground to the 3rd pole. But which one gets the signal from the pressure switch?

While I'm asking questions about gauges...

I just tried to instal an early 911 8K tach. when I plugged everything in I got nothing. I am running an MSD and have the tach signal connected to the points. Is it too low voltage to run a 911 tach. The 4 cyl. tach runs this way but run 1 1/2 x. Looks cool when I'm at 4K and tach says 6k but I'd prefer accurate.

Anybody know that one...
-Mike D.

Put a MSD on my 6, hooked up the tack, couldn't get anything, then found out the tach needed to be rebuilt to MSD spec, Hollywood Tach was recommend for the conversion. Anyway, found a local guy that rebuilt the Porsche CD Boxes. Charged me about $150, beats $1100 for a new one, Gave away the MSD. Hope this helps.

I would recommend keeping the light. It's a whole lot easier to notice the light going on than to notice a low reading on a gauge. Particularly if it gets low and then goes back up again.

And just to make sure--the wire is just a wire. The stock sender will only work a light, it won't work a gauge in any meaningful way. If you want to run a gauge, you will need a sender that has a signal that the gauge wants. As long as you're replacing the sender anyway, you might as well get one that also has a "light" sender in it, and run the extra wire.

D'OH! Just figured out it was for a Six. The above about the 'stock sender' is meant for a Four. The Six has separate light and gauge senders.

I still recommend running the extra wire (it ain't that hard) so you have the light as well as the gauge.

--DD

The sender used MUST match the instrument, so you need to know the year of the instrument to get the right sender. Earlier 911s had the instrument sender next to the thermostat, later cars had it mounted next to the alternator in the right cam oil line. There are different senders for this location. The earlier case mounted one has 10 x 1 mm tapered threads, the later ones have a couple of different sizes, depending on the year. Furthermore, the light senders are different, too. Early engines take a black one, later cars take a red one. As I recall, the threads are different, too. Good luck! The Cap'n