Help needed servicing the fuel filter / regulator on a LP5000S Countach

Thanks EarlyCat.

Well things are going have to come apart again as I got the wrong diaphragm.
Ordered the proper Malpassi RA014 diaphragm from the UK yesterday.
Hopefully it will get here quick.

Working on a Countach is a slow and meticulous process. Sincerely Vic
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Looks like I am about to corner the market in Malpassi / Filter King pressure regulator diaphragms as the one that I ordered on January 29 is in shipping purgatory (more than likely sitting in a US postal location collecting dust).
I know have two additional diaphragms on order from two different groups with expedited shipping in order to finally wrap this project up.
Hopefully one of the two will arrive before next weekend.
For the record the diaphragm is manufactured by Malpassi and the part number is FSERA014.
If you need one right away contact me as I am going to have at least one or possibly two spares laying around. LOL

 

Well I am besides myself, I got both replacement diaphragms yesterday and rebuilt the filter / regulator again.
I am still getting 7 psi on my pressure gauge and the lowest reading I can get is 5.5 psi before the adjustment screw comes out.
HELP, I am going flipping crazy. LOL

 

The diaphragm is identical in everyway and I made sure to installing in the proper orientation.
It was straight forward in rebuilding it and the vent holes is free from any obstructions.
I verified the pressure with a number of different pressure gauges, all read 7 psi and the lowest operating pressure I can achieve is roughly 5.5 psi.

 

Raymond it is hard to find the proper filter regulator here in the United States.
All of the ones I saw had the outlet piping in the downward position as opposed to pointing upward.
I have since found an exact match of this unit and may purchase it.
I am trying to exhaust all options before proceeding with a new unit all together.
One of my concerns is what if I install a brand new unit and still get a 7 psi reading?
Does anyone know definitively that the pressure setting is 3 psi?
I know a semi retired Lamborghini technician who is trying to verify the exact factory setting for the regulator.

 

I finally got things sorted out and back together.
Below is a summary of what I did and what I believe the underlying cause of the high fuel pressure.

First a bit of history, the last time the car had a major service the OEM, Corona fuel pumps were replaced with Faucet pumps.
They were replaced with high pressure Faucet pumps that can produce up to 8 psi in fuel pressure.
The OEM 67mm Malpassi fuel filet regulator is equipped with an internal pressure spring that is factory set at 7 psi, this spring measures 15.8 mm
This makes the OEM filter regulator redundant as the OEM Corona pumps cannot produce over 4 psi, however when the new pumps were installed the pressure could not be regulated down to the 3.5 psi level.

I ordered a new Malpassi stand alone fuel pressure regulator that is factory preset for weber carburetors. However this is a fuel pressure regulator only (No Filter Element) see attached photo.
When I installed this new regulator and energized the pumps it read exactly 4 psi.
My original intent was the install this after the OEM unit however I could not find ample room to mount it, so I removed it,
I noted the height of the adjustment screw and then removed the screw to access the spring and to my surprise the spring was approximately 1/8" shorter than the spring in the OEM unit, as it measured 11.75 mm.

I then decided to remove the adjustment screw and spring from the OEM Malpassi fuel filter regulator and install the shorter spring form the new unit into the OEM unit.
When I did this, I set the jamb nut at the same distance it was set at on the new Malpassi regulator which was 0.310" of screw thread showing from the top of the jamb nut.
After I install the new shorter spring at the factory preset level I energized the pumps and they read exactly 4 psi. I turned the pumps off and then reduced the pressure down to 3.5 psi.

All is finished and the car is running well.

Sincerely Vic

https://photos.app.goo.gl/3f9fHeJiECgFDqTG8