Revcounter

[Gary]

I have just bought a Caerbont rev counter(new) but when connecting to the standard V6 coil and loom it doesnt read correctly, any one had any experience of this problem, it is set to v6 mode, but reads very high and erratic.
I wondered if the brain is upsetting it and there may be a way around the problem:rolleyes:

[Matt No VAT]

Where is the trigger wire attached? + or -?

[CorseChris]

Gary,

The Bosch ECU on the 12v V6 is effectively just a transistor assisted 'normal' ignition. Not CDi or anything fancy as far as I am aware so shouldn't be problematic I wouldn't have thought. Coil + should be just that, +12V from the ignition switch. Coil negative should go straight to the ECU and feed the tacho (like it does on the Alfa).

FWIW, the Alfa dash is fully electronic as well, with programming DIP switches for assorted variants in it so at a guess, the problem you are having is more likely to be related to the installation or car wiring than the basic pairing of tacho and ECU.

You could try putting a radio suppressor capacitor on the power feed to both coil and tacho. One other question. Have you got good quality, suppressed HT leads (particularly the king lead)? If not, this can be causing your problem. Long time ago, I spent ages adding lots of extra power filtering to the Stack tacho on a TVR Tuscan racer as it kept playing up. Funny thing was, we had two nominally identical cars to work on and one was fine.... Turned out that although I did solve the problem by adding some fancy circuitry, the real culprit was a solid copper king lead causing some serious spikes on the 12v lines. Even more strange was that later models of Stack that I looked at actually incorporated almost exactly the same suppression circuitry I had invented.....