79 fuel pump v strainer

[RyanH]

1979 928
My fuel tank needed replaced and I found a good second hand one. My original tank had an internal pump with epoxy or some other material all over the exterior presumable to fix a leak. My new tank has what looks to be a strainer fitted, I haven't attempted to remove it in case I break something! There's info about pumps v strainers online but I was wondering if I fitted a second exterior pump would this help with fuel pressure/flow to the K-Jetronic system? Would this even be necessary? From what I've read the internal pump is really there for fuel vapor and not so much fuel distribution.

Any advice would be appreciated.

[stepson]

I have no experience with 1979 928s. I did have a 1980 Euro S that had fuel issues when I got it. My 1980 did not have an internal pump.

In the later cars, some models were equipped with the internal fuel pump (located in the fuel tank). Those internal pumps are now @$750-$1000. The internal pumps pressurized the intake to the external pump to only about 5 lbs of pressure to minimize cavitation in the external pump. I have replaced the internal pump with the strainer on several of my later 928s. As far as I can tell, it has made absolutely no difference in performance.

The strainer nozzle is approximately 1 1/2 time larger than the nozzle on the internal pump. Use of the strainer will require a different and larger hose from the strainer to the fuel pump

I advocate the use of the strainer in lieu of the internal pump for the cost savings, the minimization of things that can go wrong and the lack of credible evidence that the internal pump is even necessary.

[RyanH]

Originally Posted by stepson

I have no experience with 1979 928s. I did have a 1980 Euro S that had fuel issues when I got it. My 1980 did not have an internal pump.

In the later cars, some models were equipped with the internal fuel pump (located in the fuel tank). Those internal pumps are now @$750-$1000. The internal pumps pressurized the intake to the external pump to only about 5 lbs of pressure to minimize cavitation in the external pump. I have replaced the internal pump with the strainer on several of my later 928s. As far as I can tell, it has made absolutely no difference in performance.

The strainer nozzle is approximately 1 1/2 time larger than the nozzle on the internal pump. Use of the strainer will require a different and larger hose from the strainer to the fuel pump

I advocate the use of the strainer in lieu of the internal pump for the cost savings, the minimization of things that can go wrong and the lack of credible evidence that the internal pump is even necessary.

Thank you for your reply. From what I've read it aligns with your reply so I'm going with the strainer, I've also picked up a newer model and more powerful Bosch fuel pump that others have used with the strainer. My next challenge is getting the old strainer out without the insert coming free. It's stuck. Pouring heaps of release agent to the threads from the inside hoping it gets through, and have a hose clamp fitted. I'm aware there a part I can buy to replace the insert but tring to keep costs down. Fingers scrossed

[RyanH]

On a positive note, I got my pop up headlights working at the weekend!!!

[stepson]

Originally Posted by RyanH

On a positive note, I got my pop up headlights working at the weekend!!!

It's always a help to have working headlights.

You might be able to reach down through the fuel sender hole on top of the tank to "convince" the internal pump to let go. It is a TIGHT fit getting the internal pump out. It seems that it has to be almost exactly aligned to slide out.