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jimmcc jimmcc is offline
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Join Date: Jun 2005
Location: Birmingham, Alabama
Posts: 274
Originally Posted by 930 porsche View Post

On your test: I understand about connecting a ground with a 12volt power together but is it also connected with the BLK/PUR wire?

Do not connect the BLK/PUR wire to the tach.

Let me lay it out in steps as that's easier for me to explainthan an long sentenance.

1. Connect piece of wire to a ground point.
2. Connect the ground and 12 volt power to the tach
3. Do not connect the blk/pur wire
4. Turn ignition switch on but do not start the engine
5. Take the short grounded wire and repeatedly and very rapidly tap the wire to the connection terminal on the tach where the blk/pur wire normally goes.
6. If the tach is functioning you should see the tach needlejump around at the low end of the scale.

This technique only applies to SC and 930 era tachs where the tach is driven from the CDI. The 964 and beyond use a more conventional pulse to drive the tach.

Old 08-24-2009, 07:08 AM
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