oil pressure

strugiling with oil pressure on my 1981 1.6 gti i have recently fitted vdo gauges to centre console and have found i have nothing connected to my low oil pressure sensor and that the vdo gauge is showing under 1bar on idle 1k rpm I'm running 15w40 oil so is plenty thick enough is this normal the pressure sounds low to me  is it time for new oil pump any ideas dont really want to be driving it low on oil ?

what does the vdo gauge show if you hold the the rpm at 2k? should be round about 2bar at 2000rpm i think. thats at full operational temperature.

its just under 2 bar at 2k but drops to 0.8 bar at idle does this sound normal I think I will change oil pump for price of mind anyway 

Is the pressure high when started cold? sounds ok to me. saying that its not hard to change pump.