Tachometer not working

[davis911s]

I finally got my 2.7 engine running in my 77. But the tach does not work, any ideas?

Shawn

[Early_S_Man]

Shawn,

The same lead from the distributor that triggers the CDI-unit is used by the tachometer. You may want to pull the Tach out of the dash and verify that it is getting power and an interupted ground signal at the 'C' terminal from the Black/Purple wire. A long temporary connection can be made, bypassing the wiring harness entirely to test the tach and see if the problem is wiring or internal to the tach.

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Warren Hall
1973 911S Targa

[davis911s]

I have 7-8 Volts at the black purple wire at the Tach, 13+ volts to the red wire at the tach,

Is this the Tach or wiring?

Thanks
Shawn

[Early_S_Man]

Shawn,

It sounds like an 'open' wiring problem.

You will have to take the Black/Purple wire loose from the tach and check to see if there is a solid ground when the points are closed ... at the tach end of the wire, I mean.

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Warren Hall
1973 911S Targa

[davis911s]

Thanks Warren

So with the points closed there should benO or very little resistance between the purple wire and the ground, is that right. (Purple wire detached!)

What are the VOLTS supposed to read?

Also to make a long temp test wire where would I coonect the wire to the coil?

Shawn


[This message has been edited by davis911s (edited 05-16-2001).]

[This message has been edited by davis911s (edited 05-16-2001).]

[davis911s]

Warren how do I check for this 'open' wire problem? Disconnect the purple wire and.....?

Also at the wires on the coil there are NO volts registering when the engine is running, where do I take this 'test wire' from to the tach?

Please help.

Shawn

[davis911s]

OK it has been over a year with NO TACH, I am around to trying to figure it out again.

I am looking for how to check for this open wire problem, can someone describe the process please.

Thanks
Shawn

[pookie]

Just trying to figure out if davis 911S ever found a solution to this problem?
Thanks
Ryan

[RoninLB]

below the engine relay/fuse board is a 2 to 1 wire connector.. kinda not easy to find.........Ron