electric speedo conversion - dancing speedo

[clarkson23]

h recently changed mech speedo to a electric one , clocks were all ready electric(rev 1 engine in a rev 2 shell) i got a possitive from a black wire in fuse box , that gets power on ignition on and earthed it to the earthed to where the side panel is and the purple wire to the solid purple wire with white dots on the blue connector on back of clocks, now when i turn car on it dances up and down, and if you rev it it flies all over the place - now have i earthed it bad or have i got purple wire wrong? please help ive had no speedo for ages!!!!!!#
pics

[bobhatton]

If its a rev 2 car all the wiring is there. Just fit the plug onto the spedo drive in the gearbox

[clarkson23]

no mate sorry its a rev 1 engine loom as well , body was a rev 2 loom behind dash is rev 2 , and engine loom is rev 1, i know i should have re-pinned it, but any ideas?

[bobhatton]

no mate sorry its a rev 1 engine loom as well , body was a rev 2 loom behind dash is rev 2 , and engine loom is rev 1, i know i should have re-pinned it, but any ideas?

You need to extend the speedo wires from the Rev 2 loom, the body one if you have that if not the dash one down to the sensor and fit the right way round.