Tach Problem with 911 SC Engine Transplant
 

Hi all,

I've acquired a 1968 912 with a SC 3.0 transplanted into it. The tach has been changed to a 911S tach and does not work. The previous owner indicated that he hasn't had a tach working in the car since the transplant.

There is an older Perma Tune module present and seems to be working fine. It has the lead for a tach signal. The wiring checks out.

I believe I need to either get a SC tach or and intermediate switch (?).

Any guidance would be very appreciated.

Jim

Open the 14 prong connector off the engine. with the cap off, the first wire in on the top is purple/black, thats your tach wire. Jump it to a purple / black off the chassis in the left rear area and your tach should drive.
Bruce

Thanks for the reply Bruce but I don't have a 14 prong connector but a 6 which connects to the Perma-Tune unit. The 6 prong connector has a purple and black wire which I've connected the tach to with no luck.

My problem is that the signal coming from the Perma-Tune is not compatible with the 911s tach in the car. This tach is looking for a signal from the coil but, according to the info I found on the Perma-Tune, this could damage the unit ($500 replacement).

Any ideas?

Thanks again

send it to north hollywood speedometer and tell them what you have, or find an SC tach.