'70 2.2T Connecting PMO FPR

[Attylla]

Hi Pelicans

I have no experience with this and need Your help.
I'm planning to connect a PMO FPR to Zeniths 40TIN.
Does my logic make sense on how to connect this?

[Attylla]

Anyone? Please

[356RS]

Yes your correct but the blanked out one should be the return line going back to the fuel tank IIRC.

[Attylla]

Is it the left upper one as seen on the picture?

[356RS]

Fuel inlet, upper left. Return lower left. There should be some kind of a mark or stamping that indicates which is which.

[Steve@Rennsport]

JMHO, but these FPR's are for CIS/Motronic fuel pumps and do not work with low-pressure pumps without return circuits.

For carbureted applications, you need a low-pressure (4psi) pump.

[Attylla]

@Mark, thanks. My FPR I ordered on Pelican hasn't arrived yet so I will check for any indicators on which is which when I get it.

I was hoping some used it with early 911 with success and can share experience.

@Steve, I have a low pressure Pierburg pump but I want to make sure pressure is correct and stable that's why I need FPR with reading.

I really hope I can use the MPO on early engine and not only on CIS backdated to carburettor fuel supply.

[jpnovak]

Steve is correct. This will not work for your application.

[Attylla]

Ok, can You at least let me know why?

[jpnovak]

This type of regulator is a flow through design. It works by slightly restricting the open flow pressure (usually 1-2 psi) from supply to return raising the pressure to the desired amount for our 911 carburetors (typically weber or Zenith). You set the fuel pressure by turning a screw to change the amount of restriction to the outlet port on the manifold. (BTW, I thought the lower port is inlet and top port is return).



Your Pierburg pump should put out the correct pressure. The PMO regulator only works on return flow. If you have a dead-head installation then the system will not have return flow through the regulator. This means the system will equalize at whatever pressure your pump puts out.

Your 70T should have originally had a Bosch 3 port pump. These are internally regulated at 3-3.5psi. Your car should have a supply and return exiting the tunnel and connecting to the pump located under the DS rear seat pan. Additionally, your Pierburg pump should be a 2 port design having a supply and pressure output.

It might work if you connect the pressure supply from your Pierburg to the regulator and then running the return hose down to the tunnel return fuel connection under the car. Make sure the return fuel is connected at the tank.

If you have a different fuel system then please investigate and describe. Perhaps we can help you get the pressure you need.

[Attylla]

Thanks a lot Jamie

I'll verify this in practice.
In general my fuel installation in the car is 100% stock and working.

I'm currently building an engine stand to start and tune rebuilt engine outside the car.
That's why I am using Pierburg and not stock Bosch.

I thought it's essential to supply stable and if necessary correct fuel pressure before it hits the engine and not on the return from it but looks like I was wrong.

I'll report findings after PMO is delivered and connected.

[rw7810]

What Steve@Rennsport and JPNOVACK said. Hey guys good to see your alias again. Been off the net for a few years, just now back.

[gamin]

Just get in touch with Richard Parr at PMO and he will send you the correct piece. He is a very nice gentleman and always helpful.

[jpnovak]

If you are running on a stand just gravity feed the carbs. This will work just fine with a fuel source reservoir gravity feeding the floats.

Also, if you are running on a stand just run a return line from the regulator back to the fuel reservoir (tank)

[Attylla]

Originally Posted by jpnovak

If you are running on a stand ... just run a return line from the regulator back to the fuel reservoir (tank)

That's exactly what I'll do
Thanks everyone for Your help. Much appreciated.

Regards from Poland
Marcin