the tacho aint working when i bashed the ecu it came on for like 1 second any idea how to trace wat it could be

poor electrical connection in the connector, broken wire, or cracked PCB i'd say, in the order of likelihood. I think the tech docs has a diagram of the pin outs of the ecu. try wiggling the wire and see if it comes back. Note i am just saying what i'd do, i have never had this problem before.

i hit my dash and mine comes back

it hasnt got the wire for it where duz the wire go the motor that in it now never had a tacho