[spuggy]

Originally Posted by dipso

I realize I could ground my fuel pump wire and that would stop the fuel delivery, but that only kills the car after it has been driven a few miles.

Have you tried it? Based on my motorcycles, I'd expect that even with float bowls, you'd be unlikely to get to the end of the street. With CIS, I'm betting nowhere near that far.

Earlier 911s with CIS fuel injection ('73-75) have no fuel pump relay. They are directly wired from the ignition switch to the fuel pump. This third version kill-switch can be used on these cars as well as most other later cars were you will want to shut off the fuel pump (914, 944, 928, etc.).

For this version we will use a factory Porsche relay kit. This consists of a relay plug (part #901.612.333.00 - $28.49) and a round black relay (part # 911.615.109.01 - $19.20). When installed, this will have a factory appearance as seen in pre-1989 911s fuse boxes.

When this relay is installed power will flow through the relay from pin #87a to pin #30. If the fuel pump is connected to pin #30 and power to the pump is connected at pin #87a, every thing will operate normally (see diagram #3). However, if pin #86 and #87a are connected together and pin #85 is grounded, the fuel pump (or whatever is connected at Pin #30) will not operate. Pin #87 should not be connected to anything (see diagram #4).

A grounding switch can be installed to the interior of the car to activate the relay when desired. The biggest advantage to this type of switching is that a bad relay can never keep you from starting your car as the relay off position starts the car.

From http://www.dietersmotorsports.com/tech/2000/2-00.html