Speedo Reading Double?!

[sskylinee]

hi everyone

i just got my car back from the mechanic. its an N/A r34 just dropped in an rb25det neo engine and has an r32 box (temporary until i find an 34 box)

mechanic has modified the speed sender to fit and has tested it and its working. ok first problem he couldnt get the speedo wiring to the dash working. the plugs in the engine bay bellow the battery doesnt work (must have a break in the wire?) anyway instead he tried going directly to the ecu pinouts and gets a reading BUT its double!! (doing 60km it reads 120km) he tried another wire instead it reads half (doing 60km reads 30km)

so now im stuck and hes given up. i've tried a gauge place to see if they can recailbrate my dash but its too far out to do anything

i havent actually had the chance to look at the wiring yet coz the car isnt with me at the moment

but my suspicion is that they got the wrong speedo wire??? few years back, my bro attempted to install a rev/speed meter in his r32 and had the same problem with the reading (double) so he just ripped it out ( wrong speedo wire??)

i'll have a look at the wiring tmr when i pick up the car (want to fix it before considering aftermarket dash gauges etc)

does anyone have any idea what it could be?? any help would be appreciated!

thanks