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[GmasterT]

Right, thought Id start a new thread on this before I  and scrap the thing!

I have read that people have fitted facet pumps to replace the lift pumps in the tank with great success (also helps with veg oil) and wondered if anyone on here has done it?

To get the car home, I intend to borrow the leccy pump of my old landy and run it direct, but long term will get a facet pump, replace the lift nonesense with some weighted pipe and leave the standard return...

Maybe even get the pump running full time on its own power (I hear its ecu controlled?)

Thoughts? 

[Kevin Wood]

I assume you're talking about the carburettor type facet pumps (low pressure).

They would probably work OK. Begs the question of whether it's worth messing about with the standard arrangement, though. A 2nd hand TD lift pump would be cheaper and easier, surely?

If you do go that route, get one of the smaller square electronic pumps rather than the cylindrical interrupter ones - if you don't want to have to stop and hit it with a hammer every so often. Make sure you use a pre-pump filter too.

Kevin

[hoofing it]

You can add whatever pump you like just remember you will have to do some plumbing to create a return/preasure releave at the filter or you will blow out the fuel pipes/filter.
I fitted a senny fuel pump to a transit after its mech pump failed I added a bridge pipe from the flow to the return so the preasure filled up filter then returned fuel back to the tank.
I wired it into the ignition so it ran all the time

[Kevin Wood]

Is there no return to the tank from the filter, then? Not sure how it would prime in that case.

The facet pumps will just stall if there's no return, and pressure is limited to about 5 or 6 PSI. They are designed to pump against a carburettor float valve.

An injection pump from a petrol vehicle will clearly need a return line as it can achieve a very high pressure.

Kevin

[GmasterT]

Well, a couple of guys seem to have done this on 5series, abeit in a round about way.

i intend to use the standard 'cap' at the top of the tank with the new pump mounted externall to between the oe feed and the cap, then just have a weighted pipe replacing where the fuel pump is and try and keep the existing return setup (which seems to have a 1way valve on the oe holder) Not sure if the bottom of the swirl pot is the lowest point but that will have to stay in for the fuel level. If it isnt then can get the new pipe past it.

unless the ribbed pipe you disconnect inside the tank attached to the swirl is a candidate for the feed?

The other thing is having it run all the time on its own ig live as i understand the ecu controls the current one? I also understand if you wire live direct to the oe live it will also run the glow plugs.

Anyway, i have got a square solid state facet pump, 4-7psi on order with 8mm slide fit one side and same with micro filter on the other, under 40quid less than half of a new 'correct' one. I will find the link and let you know how i get on.

For now to get it home i have borrowed my landrover pump, wired to its own battery and switch to just hook up and run direct/seperate.

Can you explain the return pressure explosion thing though please? Cheers guys, all input appreciated...

[Kevin Wood]

Can you explain the return pressure explosion thing though please? Cheers guys, all input appreciated...

Fuel injection pumps are designed to deliver fuel at 3 or 4 bar or more and work by the FPR returning excess fuel back to the tankto keep the fuel rail at the correct pressure.

If there is no return line, or  one that can't take the full flow of such a pump, the pump will operate at it's stall pressure, which is likely to be up to 8 BAR. Furthermore, it will draw excessive current, overload the supply wiring and probably burn itself out.

But it's OK. You've chosen the correct type of pump for this application.

My only concern is whether fuel can be pulled through this pump while it's stopped. It "probably" can but that's something to bear in mind. if so, there's no reason to wire it to run constantly, surely?

Kevin

[GmasterT]

Ah, yeah,a little light just went 'ping!' Plus on diseasels it needs the return pipe varible to bleed it, although thats more or less what you said, its the not thinking petrol style too i suppose.

Anyway, got it home. The pump from the landy wasnt really man enough, but kept it below 2k and she plodded home.

Bit of hit and miss on pipe length inside the tank, but not to bad, retaining the oe return. Having issues removing the swirl pot as i think utalising that strange second pipe may be a good feed, with some holes drilled in the swirl pot! But then is the swirl pot needed as a collector or just a novel way of mounting the pump? The T piece bit seems a little odd tbh