cars with carby engines dont have the speed signal due to different speedo
when i wire up carby cars with efi engines
i dont wire up speedo or ecu light cause if u dont do the speedo
wire then the light comes on
one way around it is to fit a newer speedo from an efi car
but if u leave it off on a 4a engine its ok
if u leave it of on a 1j and its auto then it might not change gear