82EUROATM

So I have been chasing down a voltage issue but having trouble narrowing down where my problems coming from.
first started with voltage drop in my radio shutting off when I put the headlights on and in drive at a stand still.
so I put a new battery in and checked the charging system which reads 13.5 when nothing on but with the lights on it’s 12.5 so I went to power lead of the radio and it drops to 11.7 and even lower when I turn in the lights.
the issue is getting worse where the temp gauge is jumping erratically and getting pinned where it appears it’s over heating but the engine at the thermostat is 190 degrees and the oil pressure gauge is also giving a false reading.
when I accelerate hard with all the lights and radio on I lose power at high rpm also.
I’ve checked and cleaned all my grounds but still having issues.
the car doesn’t overheat and the fan kicks on at 205
the way it’s supposed to.
im leaning that my alternator is shot or my green wire or ignition coil.
alternator is old and my green wire looks like it’s time to replace but not sure

Mrmerlin

sounds like you know what to do
I will suggest you replace the green wire with a new Bosch wire,
its more expensive than the URO version but,
the URO version might not fit properly and can short out,
so get Bosch,
Also you need at the least a new voltage regulator with fresh brushes. prolly the slip rings are worn as are the bearings,
take the unit to a re builder,
make sure to get a Bosch regulator,
or have them replace the brushes in the regulator you have if its bosch

Petza914

Also, if you have any extra electrics like an amped stereo, HID headlight conversion, etc, it would be worth getting a higher amp output alternator from Greg Brown.

Instigator56

According to GB, currently his alternators work on MY1985 and above. However, I believe that he's looking into getting it to work for someone with a 1984 Euro, so that mod could work also for your 1982 928.

Speedtoys

These use -less- current. By a mile.

82EUROATM

I just took it out and this thing looks old I have a local rebuilder that I’m going to on Monday so I’ll see if he can rebuild it for me.
I don’t have the hose that runs into the fender or the sensor but I see the plug in the fender where the sensor plugs into.
could not having the hose caused this issue and going forward should I put the hose on

Instigator56

@82EUROATM you can source the hose from Porsche (OEM) or from GB (silicone aftermarket). I believe that the missing sensor that is in the hose (and plugs into the fender) is the exterior sensor for the car's climate control system. I don't believe that the system will work properly w/o that sensor.

Good luck on the alternator rebuild.