My tach...I'm stumped! Help?
 

Last fall, I converted to a crane optical ignition with no problem (using a Permatune CD unit). My tach worked fine, the car ran well, I was happyman :) This summer, I replaced the Permatune unit with a Crane HI6 unit and LX92 coil. The car runs fine with this set up, but the tach doesn’t work, which I anticipated after reading the various posts here. I got the tach adapter to get my tach function back, and that's where my problems began. Now I'm sadman :( When I install the adapter as instructed, the car won't fire. She cranks, but she won't start. Once in a while she teases a little by almost firing just for a second, but then goes back to cranking. If I disconect the adapter, she fires right up. :confused: So I called the tech guy at crane and they had me send it back to them for testing. I just got a new adapter back today, installed it, and.... same thing.:eek:

The tach is a stock, VDO unit from a 1969 911L. This may be important as I understand this was different than that used on other models. Before the HI6/crane coil, I had to have another adapter on my old coil to get the tach to work, but that won't work with my new set-up.

I'd really like my tach back. Any ideas???

Yes, it's the crane tach adapter, and no, it makes no diference whether the tach is connected or not.

If the objective is simply to get the tach back, then find a tach from a 70-73 911 with a similar red-line to yours. It should look correct (I think the 68 looked like the 70-73), and the later tachs are set up to work with higher-output signals. I believe they will work with no adaptor. Or so I have been told.

Not sure what's going on with the adaptor...

--DD