Alternator Output

[NCGermerican]

I can't thank you all enough for your help with this. I'll try to address the most recent questions and thoughts:

Gauge behavior:
*It's important to point out that I have the 911 style gauge pod mod (love it!). When screwing the housing to the bezel, the rings do appear to put pressure on all the gauge faces. Not sure if that makes any difference or not.

From left to right:
1) Coolant Temp gauge - works as intended

2) Fuel level gauge - with key on but car not running, gauge shows the correct fuel level. When starting the car, it immediately moves to "full". If I "flick" the lens, it will move down to correct level, then move back to full. Note that I cleaned any varnish off the very thin metal strands on the fuel level sender in the tank about 1.5 years ago.

3) Speedometer - works as intended

4) Tachometer - this is now the second tachometer I've tried and issues are consistent with my original. I have an F9 DME. Tach works as intended at idle and under normal acceleration. Under heavy acceleration, the gauge will start strange behavior (will either "flop" around or act like it's "stuck") starting around 3.5K RPMs. It returns to normal behavior when I let off the pedal.

5) Oil pressure - stays between 3.8 and 4 bar regardless of cold or hot. Has been this way before and after engine rebuild. Will be replacing FPSU with a new Porsche one when I change the oil after rebuilt motor break-in.

6) Voltage - stays consistently at 14v on the gauge

Battery/alternator/starter wiring
All wires replaced before my ownership, but still look very new and not oxidized. Look to be larger than stock wires but unaware of what kit was purchased.

Stereo/amp power/ground
Powered directly to the battery and common grounds to chassis in the trunk. It's not a massive 80s/90s thunderous boom style system. Just one small amp for door/rear speakers and separate to power 8" sub in the "cubby"

Grounds
I cleaned all of the grounds I know of (behind headlights on both sides and under dash) about a year ago. I used some sandpaper to get off any oxidation and also hit them with some Deoxit. The motor grounds were cleaned when I replaced the motor last month. The one I haven't yet touched is the main negative that bolts to the rear of the firewall (in the battery cavity). However, those are relatively new wires.

Gauge cluster main grounds - anyone have a pic that shows where these are? If each gauge has it's own ground, I'll run a separate wire to ALL of them.

[Tom]

You mean the Carpokes 911-style gauges with separate lenses, etc.? Did this all start after installing the kit? I can't really imagine any way for it to cause that collection of issues? A bent needle could be hitting the lens, but that wouldn't explain most of those issues. Could be multiple things going on there... I'll look up the ground points for you in the meantime. I have the F9 DME too, and no tach or other gauge issues...

[NCGermerican]

You mean the Carpokes 911-style gauges with separate lenses, etc.? Did this all start after installing the kit? I can't really imagine any way for it to cause that collection of issues? A bent needle could be hitting the lens, but that wouldn't explain most of those issues. Could be multiple things going on there... I'll look up the ground points for you in the meantime. I have the F9 DME too, and no tach or other gauge issues...

Yes - the Carpokes 911 Style gauges, but I really don't think they're causing the issue. I've had weird gauge problems with one or another ever since I owned the car.

I would love to invest in another gauge cluster, but finding one with low mileage (meaning low wear n tear, no faded orange markings, etc) is next to impossible - especially with a 180mph speedometer (87+ turbo's). I was also looking at that ribbon replacement (forget the name) but I have yet to read of someone with a successful install.

If you find the ground locations for the gauges, I'll wire it up to a separate chassis ground and see if that works.