400 Fuel Pumps

Even with 1 pump running, there should be at least some pressure at the carbs.
You can see how there are connected here:
Ferrari 400 GT (Mechanical) - Fuel Pumps and Pipes: Page 008 | Order Online Eurospares

 

Good day,
Before I would replace the pumps, I would start with the basics and remove and examine the fuel filter and the hoses. It is possible you have a plugged filter or perhaps a collapsed/worn fuel line.
Cheers,
Sam

 

Dont know the 400 system but looking at the eurospares diagram it appears there are 2 pumps supplying the fuel to the carbs via a single pipe and a similar return line. I would assume that the outlet of each pump has a non return valve, so either the non return valve is stuck shut. Other option is that the fuel is going back through the other pump- ie 1 pump is running and other is not. No pressure makes me think non return valves if fitted.
Eurospares pt list is in Italian so u need to tranlation.
Hold off buying pumps until you break the pipes and run pump outlet into a container from each pump

 

Good day Mike,

This is a similar arrangement to the carbed Boxers that also have two pumps, and there are no dedicated non-return valves. Effectively the pumps themselves are the non return valves

Cheers,

Sam

 

If u can suck it up then no blockage -there must be something between the supply and return lines so as you develope pressure from the pumps, otherwise it would just go around in a circle

 

As the tanks are lower than the engine you would expect that-can you disconnect the fuel supply line in the engine room and try pumping into a container- that will prove the supply line, when doing it your putting finger over the end to see if it develops pressure - if no pressure we are back to the pumps-either no discharge pressure or 1 pump is pumping through the other.
We can then disconnect the wire off 1 pump and block off the outlet pipe, this will test 1 pump, them do the same on the other to compare both pump outputs

 

If you get it on a ramp you should be able to use a 4 amp battery charger as a power supply direct on the pump terminal ( it should be enough) if you get fuel and it starts then it is electrical, if no output of fuel, do on both and see if 1 buggered, donr see both pumps failing but can see fuel going back through 1 pump

 

I'm not sure if the dual fuel pump solution was designed to offer a limp-home mode in case one of the pumps died or maybe a pump with sufficient flow was not readily on the market. I have been using a single Carter P4070 pump and it provides plenty of volume at the correct low psi for your carbs.
Take a good look at your fuel lines too and see if it isn't time for a change.

 

Brave man having a 400 as i believe parts are rare and expensive - any pump might do if it pumps enough fuel
Have a look on Superperformance site, they have 3 types of fuel pumps, 75-120- 1100 quid plus a repair kit and a load of other fuel bits re a 400

 

Nice to able to afford a new g/box. I am living on tesco bears to run a 430

 

The Carter pump is somewhere around 7psi but Weber experts suggest 2.5-3 is better. I bought a pressure regulator but haven't installed it yet because it runs well as-is.

 

It would be interesting to see how much pressure is actually at the carbs. I'm sure quite a bit of fuel pressure is bled off from the return line but I'm not sure exactly how much.

 

Mike, I had to go to google to discover wot the 'ell you're talking about.

Barny Chocolate Kids Sponge Bear 5 Pack 150G
Suitable for vegetarians £1.69
Soft sponge cake with chocolate filling. Sponge bears with a hidden chocolate centre

Discover the world of Barny He's a playful bear with a cheeky chocolate centre.
We bake them with quality ingredients such as: flour, eggs, milk, chocolate

An exciting bear-shaped sponge snack with a delicious chocolate filling, providing a little discovery in every bite. Carefully baked with ingredients including wheat, flour, milk, chocolate and eggs. Barny comes in a pack of 5 individually wrapped portions
No artificial colours or preservatives added. Suitable for vegetarians.

[this last was very reassuring]

 

Good try, we have tesco supermarket and i use their baked beans- 3 stars for effort mind you.

 

I think you may find a single Facet will not flow enough fuel for high speeds and loads, instantaneously our cars may need 4 mpg (U.K.) ? Insufficient flow could cause starvation, weak mixture, detonation, boom !


Sent from my iPhone using Tapatalk

 

Nice easy fix then
How much are the pumps each ? Assuming you have 2 scrap pumps be sure to clean out the pipes in case the pump has been machining itself to bits and put the crap in the system
If you need the rubber mounts with the threaded ends , have a look at RS Componients web site as very cheap