hi my ef v8 has a small problem the voltage at the alternator is reading 13.9v idling and in diagnostics mode it reads around 11.5-13v idling also diagnostics mode shows 2 bar oil pressure on idle and the guage reads around 1 i think its related to the low voltage. all my ground cables are good i have put in some bigger 4 gauge earth wires and a bigger 4 gauge alternator wire voltage from the positive on the battery to the negative on the body reads 13.9v so i doubt its a bad earth under the engine bay ive checked the earth near the windscreen for the dash and that seems fine. when i switch on the ac the voltage will drop on the dash and same with the headlights but the alternator and battery voltage stays at around 13.9v car has no problem starting battery terminals are new and the battery posts are clean. fairly new battery.
is there a positive wire that could be causing this? im not too sure what to look for ? any suggestions would be great. thanks
