Been having fuel starvation issues with my ae71, which has a weber carb and aftermarket fuel pump. Would I be correct in assuming that it is better to have the fuel pump near the tank? Seems it doesnt suck very well as it is, damn dodgy job the previous owner did xD. It's a brand new pump, old one died due to running dry and rust particles, lol.

Most aftermarket electric fuel pumps have to be mounted under the level of the fuel tank, so if it's not start there.

Facet's, Mitsuba's etc are all meant to be located near the tank, ideally lower, and act as a push pump as you suggest. Mitsuba's have a built in filter, whilst facet's don't. A very good idea to use a pre filter if not otherwise fitted.

 

Factory in tank pumps always incorporate a particle sieve at the pickup.

 

So whatever electric pump you have, locate it near the tank. Make sure you soft mount it, as noise can be very annoying.

Absolutely correct! The low pressure pumps don't suck very well.

The instructions usually state that they should be mounted within 30cm of the fuel source.

Cheers for the replies guys, it is infact a Facet branded pump, shall get stuck into mounting it up underneath the boot tommorow. I swear I havent found a single thing done correctly on this godamn car since I started working on it.

There is a phenominon known as 'vapour lock' as well.

 

Where, if a pump is asked to suck fuel a long way, it can lower the pressure at the pump inlet enough to boil the fuel (very local boiling I'm talking about, around the impella blades of the pump), and essentially it casues the pump to try to pump fuel vapours, which is not a good idea.

 

This phenominon is worse if the fuel is hot already (from either too big a pump, or fuel lines running close to hot things).

 

so yeah better to get as much positive pressure as you can at the inlet of the pump, which can be done by mounting it closer to the tank, or as suggested lower to the tank.

I had a facet soft mounted to the boot floor in a Datsun 1600. It was hellishly noisy.

Ran one hard mounted under the parcel shelf. Not for long though.... Wasn't to bad mounted on the outside of the spare wheel we'll on rubber isolators.

Only time a facet gets noisy is when it is trying for fuel, the one I fitted the other day came with a filter to screw in.

Only time a facet gets noisy is when it is trying for fuel, the one I fitted the other day came with a filter to screw in.

 

This has been my experience. The old one was hardmounted to the firewall, and unless you knew what you were listening for, you couldnt really hear it over the sound of the (loud) 4ac lol. Until it started to run dry that is, at which point you could probably hear it 10 metres away over the engine noise. Probably did have some vapor lock going now that I think about it, considering that it was fine some times and not others.

 

Looks much tidier, just above the tank near the rubber hoses between the tank and the hardlines.

The facet you have looks like the "up to 4 psi" model, this may be part of the starving problem. The model up from this one is the 574A, has a 4-6 psi (80 ltr/hour) range which is probably more what you need since your running a weber.

 

cheers!

Edited July 27, 201313 yr by Clapped out

Disagree. I ran twin 40 DCOE's with a 4psi facet.

Webers dig it at 2.5 - 3.5 psi. I'm using a stock k motor pump on my 32/36 dgv. Stock pumps move 2.8 - 4.3 psi from factory.

All sorted! Thanks for all your replys guys, managed to get it all working well :D. If I had to name the issue I would say it was probably vapor lock from the long path from the pickup and the pump mounted at the top of the firewall.

 

Cheers.