early fuel pump to late fuel pump

[DAS914]

Hi
Just a question. Can you substitute the later fuel pump for the 1973 version??? If so what has to be done.
Thanks, Mike

[Dave at Pelican Parts]

Yes, you can. You will have to do some creative work adapting the fuel line sizes--the inlet on the late pump is much larger than that on the early pump. You can eliminate the "R" line from the pump to the return line in the center tunnel, and eliminate the Y fitting there as well. The return line should just go from the fuel pressure regulator straight to the tank in that case.

You can either duplicate the factory 75-76 setup, using factory parts or equivalent, or you will have to brew your own setup. Not that hard, I wouldn't think, but you will have to do some adaptor magic.

--DD

[Tidybuoy]

I did exactly what dave said - switched to the 75/76 setup.

I got rid of all the extra fuel lines (tee,s y',s etc). Switching to the later pump is easily done. the fuel lines out of the tank, to the filter, and then to the fuel pump are very easily done. But, when you get to the back of the car, the fuel lines coming out of the tunnel are a different size than the lines going around the engine. so, you will have to convert the larger line down to the correct size or you will get a dangerous leak. I simply used a plastic reducer. This has worked well for several years.

Since I had a '76 parts car, I used the '76's original wiring that goes from the relay board to the front trunk. However, after hours of trying to feed the OEM wire thru the original harness, I gave up and just ran the wire to the front via the Vern way (rigged). Now that I have the engine out and doing some rear suspension work, I'm going to try again to get the original wiring fed thru that rubber tube - I want it perfect!


Vern

[DAS914]

Thanks for the reply. What size are the inlet and outlet ports on the newer pump?? I have to install "new" gas lines through the tunnel and I wonder if I can change the line size there.
Regards, Mike

[Dave at Pelican Parts]

From here:
http://www.pelicanparts.com/914/technical_specs/914_18FI_diag.htm
The diagram is for a 1.8, but all 75-76 cars had the fuel system setup pretty much the same way.

7mm inlet (fitting), 12mm outlet (fitting).

--DD

[Tidybuoy]

I'm not sure of the line size. I know that the lines thru the tunnel are two different sizes. and the output of the '75/76 pump is smaller than the input which matches up to the smaller tube.

Your best bet is probably to remove the tank, measure and figure out what you need and then get the parts. Another idea, many guys replace the plastic tubes (in the tunnel) with big-rig truck brake fluid lines. I haven't done this but I would guess that you could get everything just right doing it that way.