Hooking up my tach!

[drophit]

I have a 75 911s with an 87 Carrera 3.2 in it, the tachometer was never hooked up and i currently have 1 red wire in the front trunk area marked tach that is not hooked up to anything.

Is there a how to anywhere to get this connected correctly?

Z

[Jonesee]

post this to the 911 technical forum.

[Henry Schmidt]

Originally Posted by drophit

I have a 75 911s with an 87 Carrera 3.2 in it, the tachometer was never hooked up and i currently have 1 red wire in the front trunk area marked tach that is not hooked up to anything.

Is there a how to anywhere to get this connected correctly?

Z

The trigger for the tach in a 75 [points CD] and a 3.2 [Motronic] signal are different.
John Bell, on this forum can convert your tach to read the 3.2 signal.

[wjdunham]

You need to buy a "Tach Adapt" unit which will take care of it for you. I put one in a 69 with a 3.2, the Tach Adapt takes the signal from the Motronic and converts it to the voltage levels required my by 69 tach. It should have settings for your 75 tach as well. Google it and you should find it. Was in the $75 range if I recall.

Bill

[E Sully]

Do you have the complete 3.2 DME harness in the car? You should trace the red wire out to see where it leads to. The DME harness uses a Bk/V for the tachometer signal.
I'm not sure about the '75 tachometer, but my '73 tachometer worked with the Bk/V wire from the 3.2 harness.

[inaminit]

Get a color copy of the 87 wiring diagram and determine the pin with the Bk/V wire in the engine side of the 14 pin connector. Then find it on the chassis side of the connector and make sure that they connect.
+1 for the tach adaptor

[boyt911sc]

Originally Posted by Jonesee

post this to the 911 technical forum.

Jonesee,

Were you aware that you replied to a 18-year old post? Same to others.

Tony