FUEL PRESSURE GUAGE WIRING GTi MK1

Hi I have a MK1 gti with a fuel pressure guage fitted but not connected .
Does anyone know the colours (two wires) on the engine loom

not standard fitment so look for any random wires left over

Hi yes when I plug it into harness at the dash it pings over to maximum.There are 4 wires in the engine bay spare ,but the colours are very faded and they show no voltage or earth  .It was built by VW in 82 as a GRP A rally car so probably only they would know .Thanks anyway

ok assuming its the same as an oil pressure gauge this means the wire is disconnected in the engine bay, can you trace the wire from the gauge to where it goes to the bulkhead? hopefully it'll help you track down the matching colours in the bay.

if the wires are that faded it may be worth stripping the loom out to check it all over, the copper might be a bit crusty by now