prosport gauge strange issues
 

ok removed i af prosport gauge from my classic and a friend has had it fitted in his

this is what happens
ign on does the opening sweep as normal but the needle moves up and down a little , turn car over and the needle drops to the bottom and wont move ???

have also noticed that when the ign is on and the needle is moving about (without car running) and you turn the lights on it does the same and needle drops to the bottom again

have had a quick check and the tested the wires and all seem to read on the meter as they should

anyone???

faulty gauge if all is well with wire, but where is it earthed, have you tapped onto a wire or is it chassis ground

Make sure that it has the correct wiring:
PERMANENT live,
Switched ign live,
lights
Earth.

And that all are correctly wired.

Then look to the sender wiring: is it the correct sender for the gauge, (NOT all are compatible)?
Is it wired correctly, all plugs FIRMLY in place?
Does it have an earth if it needs one, (ie: if screwed into the engine block, try earthing it's casing to the block with a short piece of wire)?

cheers for the reply
gauge was working fine when removed,
as i didnt fit it think its best to start again
af gauge doesnt have a sender just one wire you connect to the ecu

i have checked all the wires with tester all all seem fine, not sure how to test the wire going to the ecu with a tester