Tried to fix bouncing tacho with a tachofix but now nothing

[Martyn123]

Hi,

Rover v8 engne with Megajolt, rev counter is a cai (part of Smiths range) Eclipse analogue tacho.

The rev counter was working fine and smooth up to about 3500 revs when it would suddenly start bouncing so i have bought a tachfix to try to solve the problem, with this connected the tacho needle jumps when i switch ignition but when i start the engine nothing happens at all.

To clarify,

My tacho has wiring as described in the manual

Green, lgnition power source
Black Ground and sensor wire
White/black tacho output ECU or W terminal on alternator but not both
Red/blue contact breaker (low tension side of coil)
White/red Dash lamp power
Brown/slate Tacho hourmeter only


The tachfix has the following wires,

Red/blue Live
Yellow, I have tried connecting this to both white/black and the red/blue without success
Black/grey Earth
Blue Number 2 pin on EDIS

I was advised to cut the white wire from the coilpacks which went into the black/white in the tacho when fitting the tachfix and connecting this to the yellow on the tachfix,


Please can anybody tell me why the tachfix is not working