Fuel pump wiring 77 911

[cfassett]

Dumb and simple question... The fuel pump was missing from my '77 911 when I bought it. I'm about to put in the new, along with some new hoses, etc, which just arrived from Pelican.

So, which of the wires down there is the positive/negative?

[blg5035]

Black is positive
Brown is ground

[cfassett]

Thanks, Ben!

[M491Cabriolet]

BTW, if I’m not wrong, the contacts on the pump itself will be two sizes. The bigger one (5mm nut) will be negative, and the smaller (4mm nut) will be positive.

[cfassett]

Thanks for the guidance! Got the thing wired up, and the front hoses replaced today. Then ran some fuel through the system, out of a pirtablebgas tank.

Discovered a fragile and leaking hose in the engine bay. Keep in mind, this car has been in someone's yard since 94.

Can you tell me where this hose routes to? It is attached to a 3 way splitter through a coupling, and runs parallel to what appears to be the inbound hose on the left rear fender inside wall.

[Knockdown]

I believe the 3 way Tee you are referring to is for the fuel return line back to the tank. It picks up the return fuel from the fuel distributer pressure regulator and the warm up pressure regulator. The fuel supply line going to the accumulator and the return line off the Tee route down to the tunnel area under the transmission mount and connect to the polyamide lines running through the tunnel.

[Knockdown]

[cfassett]

That looks right. I appreciate the diagram and the help!

The CIS is so complicated... If they weren't so expensive, it's enough to make me want to pull it out and switch to carbs!

As it is, it's time to pull all the rubber lines in the back and replace them all. The polyamide lines appear to be good and flexible, and I've read they last forever. Would you all recommend replacing the polyamide lines too, or is it generally only the rubber lines that rot out on the likes of a 77?

[boyt911sc]

Originally Posted by cfassett

That looks right. I appreciate the diagram and the help!

The CIS is so complicated... If they weren't so expensive, it's enough to make me want to pull it out and switch to carbs!

As it is, it's time to pull all the rubber lines in the back and replace them all. The polyamide lines appear to be good and flexible, and I've read they last forever. Would you all recommend replacing the polyamide lines too, or is it generally only the rubber lines that rot out on the likes of a 77?

cfassett,

CIS is NOT so complicated as you think. You are simply not familiar yet how CIS works. It takes time and practice to understand it. Since you are working on the revival of this car, make sure you use fuel injection rated fuel lines. The rubber fuel hoses commonly used in a carb set up will not last long in CIS. In case of a flow restriction, the pressure build up would register as much as 100 psi.

Before you attempt to start the car, learn to test run the FP. Double check the fuel lines and make sure there is NO sign of fuel leak or wetness. Leave the FP running for several minutes and inspect again.

Everything you need to know in CIS is available in this forum. There are plenty of helpful guys to guide you. All you have to do is ask (nicely) and you will receive. Welcome to the club.

Tony

[cfassett]

https://www.pelicanparts.com/More_Info/21340600-M20&SuperCat=Y&SVSVSI=1047.htm

Are these the guys I need for the engine side (type and size)? It is what was used up front.

[boyt911sc]

Originally Posted by cfassett

https://www.pelicanparts.com/More_Info/21340600-M20&SuperCat=Y&SVSVSI=1047.htm

Are these the guys I need for the engine side (type and size)? It is what was used up front.

Fabricating CIS fuel lines is not for the novice unless you are willing to take the risk of accidental engine fire. Leave this job to the professionals. The amount of money you save is not worth the risk. While I could successfully fabricate fuel lines, I use them only for my projects. And will NOT sell them to others.

Contact Len Cummings aka (BoxsterGT) in this forum. He does excellent fuel lines fabrication better than anyone else we know. Stay safe.

Tony

[Knockdown]

I didn’t replace my tunnel lines on my 77 and from memory I believe the fuel line I used were high pressure 7.5mm ID. If you do decide to do this yourself, make sure you are using high pressure clamps, I used Oetiker clamps.