Is the Fuel Pump in My 1973 911T Unfused?

[911gt2]

Hi everyone,

I’m currently reviewing the electrical diagram for my 1973 Porsche 911T (originally an MFI car, now converted to Weber 40 IDAP 3C carburetors). While tracing the wiring, I noticed something odd about the fuel pump circuit, and I’d like to confirm if this is correct or if I’m misinterpreting the diagram.

I used this diagram

What I’ve found in the diagram:
- The fuel pump (8) is wired to the left side of fuse 7.
- The left side of fuse 7 also has a black/red wire that gets power from the ignition switch (15, switched +12V).
- The right side of fuse 7 powers the rear window heater (35) and the glovebox lamp (24).
- This means that the fuel pump is being fed from the ignition switch (15) but BEFORE the fuse.

My concerns:
- If this wiring is correct, does that mean the fuel pump is not actually fused?
- Could Porsche have fused it elsewhere, or is it just an unusual design choice?
- If it’s really unfused, wouldn’t that pose a safety risk?

Additional context:
- The wiring diagram is for an MFI-equipped car, but since mine has been converted to carburetors, I want to ensure the electrical system is properly set up.
- I have traced everything back in the diagram, and it appears that the fuel pump is not protected by fuse 7, only using it as a distribution point.
- If this is normal, I’d like to understand the reasoning. If it’s wrong, I’ll look into properly fusing the circuit.

Does anyone have experience with this? Can someone confirm if the fuel pump in a 1973 911T is truly unfused in stock wiring?

Thanks in advance for any insights!

[gerakroo]

You are absolutely right, the fuel pump is unfused. This is 100% original. There are more circuits unfused, the same counts for the instrument lighting and supply. Its been running for many years, but I do agree that its not really German "Uber Engineering"

[cbpiii]

If you need to stop fuel from being circulated when ignition is on, it is easiest just to unplug the electrical connection at the fuel pump.

Bert

[NorthernThrux]

I think it's a failsafe approach actually. No fuse means the fuse can't blow while you are driving and stall the car at an inopportune time. Disconnecting the red/green wire at the Fuse 7 location is what I find easiest to turn off the fuel pump. I don't like connecting and disconnecting the more weathertight connections under the car if I can help it. If you do want to fuse it, just move the red/green wire to the other side of the #7 fuse. You shouldn't need a higher fuse rating unless you regularly use your rear defroster, which doesn't work on most of our cars anyways.

Ravi

[911gt2]

Thanks all.
I will leave it unfused. My pump is in my smugglers box so it's fairly well protected there. So I guess there won't be any problems.