Hi Guys
I have recently fitted a Lumenition Optronic Ignition System to my 1971 era TF and the car now runs beautifully.

However, the rev counter has ceased to work. I assume because I have substituted the old coil for the High Performance Optronic Mega Spark 4 coil and done away with the dizzy connection.

I have demounted the rev counter and find that the instrument has three terminals on the back, one a spade terminal that carries the green + supply wires and two terminals carrying white with black stripe wires, presumably negative - one with a bullet terminal, and one with a female termination.

I have buzzed the white/black stripe wires and the female terminal has a continuity with the negative terminal fitted to the coil. Question is, where can I terminate the other wire to make the taco work again, or is there some incompatibility with the instrument and the new Lumenition coil.

Any suggestions would be very welcome.

Hi Eric - sorry to hear that ignition update to Kermit has led to tacho problems.
You are not alone in this it seems
Early electronic tacho are designated RV1 type and often do not work well, or at all, with electronic ignition conversions.
Later models are designated RVC type which are usually ok.
There is a Lumenition Tech Sheet 15 on the subject, I will email you a copy.
There are various rewires done for the RV1 tachos but if you get it wrong you blow-up the ignition module.
The recommended method seems to be to get the RV1 modules redone internally.
Speedy Cables at Swansea do this - see Tech Sheet
We got Rocket's tacho rebuilt by Alan Davis at The Gauge Shop, Edenbridge, Kent so he might be able to help.
HOME 01732 863073
MOBILE 07773313474
info@smiths-gauges.co.uk

I hope this helps and good luck - Chris

Thanks Chris
thats very encouraging saves me tearing my hair out .
Greetings to the Ooops lady
regards Eric