1971 911T Gauges

[TommyV]

I'm working on getting my gauges hooked up and working. This is a roller that was missing several gauges when I got it. I have the Tach hooked up but it doesn't work. I read a thread about Tach's from certain time periods needing a 24 volt square wave signal (up through Oct. of 71). I bought the tach separate from the car. How do I tell the date of the tach? I attached a pic showing how I have it hooked up. I'm interested in feedback if i have it wrong.
I also included a pic of a bulb holder. I'm missing one of these. Where do I source one and how would I describe it so someone would know what I mean?

[classic]

That's a 2.0 Lt Tacho, you can see the threads for the knurled screws that hold the gauge (69 and earlier).

I would guess that you don't have an intermediate unit? In which case you'll need to either get the Tach adjusted by someone like NHS or fit a Tach adapter....

As for the bulb holder that's easy...

http://www.stoddard.com/911-1965-73/...41-902-00.html

[TommyV]

Thanks Tony. Where is the intermediate unit? I'll look to see if I have one (probably not).

[Jim Breazeale]

That's a 2.0 Lt Tacho, you can see the threads for the knurled screws that hold the gauge (69 and earlier).

I would guess that you don't have an intermediate unit? In which case you'll need to either get the Tach adjusted by someone like NHS or fit a Tach adapter....

As for the bulb holder that's easy...

http://www.stoddard.com/911-1965-73/...41-902-00.html

Interesting that it has a 4/71 date stamp on it, though.

Regards

Jim

[Great_Escape]

I was told that printed on the inputs on the back of the tach one of the three terminal will have either a 1 or a C above it. If it is marked with the 1 it requires the boosted voltage. I know the tach in my car 69T had a 1 and needed a adapter to work with the MSD unit I added. Good Luck

[classic]

You can see what one looks like in this post (sorry I can't post photos for some reason at the moment)

http://www.early911sregistry.org/for...ermediate+unit

You should find it on your electrical panel in the engine bay, and SL33 wiring diagram shows how it should be connected.

Where have you got the black/purple hooked up in the engine bay? Is it directly from the dizzy?

My 69T was optioned with CDI and has the intermediate unit to drive the Tacho, which would appear to be a 69-70 thing.

[classic]

Interesting that it has a 4/71 date stamp on it, though.

Regards

Jim

Nice catch Jim......interesting, I would assume that it's been worked on in the past and had threaded posts added.

I think you may need to send the Tach to someone like NHS to see what you have, as it does appear that the stamping doesn't match the attachment method.

[TommyV]

You can see what one looks like in this post (sorry I can't post photos for some reason at the moment)

http://www.early911sregistry.org/for...ermediate+unit

You should find it on your electrical panel in the engine bay, and SL33 wiring diagram shows how it should be connected.



Where have you got the black/purple hooked up in the engine bay? Is it directly from the dizzy?

Thanks for the thread link. I don't have one (IU), my electrical panel in the engine bay was robbed of parts before I got it. I've got a friend 1 state over that has a lot of spares, so he may have an Intermediate Unit. The pic really helps.

Your linked post indicates tach's after Oct 1970 don't require an IU, but I found another post that said Oct 1971. Your link and the one I found were both by 304065, but your's is later, so I'll assume it's correct. It is strange that the date stamp is 4.71 on the tach. I didn't realize the mounting posts meant it was earlier.

The black/purple wire is hooked directly to the dizzy. I do need to trace it to make sure I've got the right wire in the dash. My harness was made up by my friend as I didn't have one and mine, in the engine bay, was messed with, so the black/purple at the dizzy isn't the same black/purple in the dash, he used the same color, but not identical markings. The one in the dash should look like the wire hooked to the fan motor but it doesn't, maybe it's faded because of the tach missing and the car sitting in the sunlight, not sure. I know I had a tough time deciding that was the one. Can I run a continuity test from the dizzy to the wire in the dash to make sure I've got the right one?

[TommyV]

Ah Ha! I took a pic of the Elec Panel in the engine compartment this morning on the way out the door. I do have an IU!
I need to make sure it is hooked up correctly! Thanks for the help and insight!

Also, here is the back of my Tach, I have +12, 1, - for terminals.

[TommyV]

Spent some time over lunch confirming the Intermediate Unit is hooked up correctly and it appears that it is. I guess I can put a voltmeter on the black/purple wire while it's running to see if I'm getting a signal. My buddy in Illinois is going to send me another Intermediate Unit and a couple of working tach's to see if one of them will work.