Thread: Replacing 300tdi lift pump with a Facet Posi-flo electrical pump

Mine are working fine up in the engine bay yes the single wire from the fuel cut solenoid has enough juice to power up the fuel solenoid, a fuel pump 2 normal horn type relays and a 12v400a solenoid for a winch.

the reason you put the pump down near the fuel tank is to speed the priming process and to prevent the pump drawing air through the sedimentor if a seal leaks. If you were going to do that I would strongly suggest that in that installation you would need to put a relay in.

Thanks Dave

As always your knowledge is invaluable.

I think I will install in the engine bay to make wiring it eaiser and also might remove the mechnical lift pump and fit a blanking plate.

Did you fuse the positive wire?

nope, its fused in the cab.

I just fit a loop hose to the inlet/outlet of the lift pump and left it there.

Thanks Aaron and Dave. My lift pump was leaking and was time for a replacement (outlet line was loose). The facet Posi-flow looked good so went ahead and got one, thanks for the link Aaron, called Powerflow direct and picked one up, didn't need the auction. It comes with 5/16" connectors, so to keep the lines the same size, with a little bit of grinding and drilling, silver soldered a 5/16" barb fitting to a spare filter banjo, and to a plastic push-in connector for the stock line (not really push-in but with gentle heat works well). Mounted it up in the engine bay and supplied power with Dave's instruction, works great, no leaks. Made a blanking plate to replace the original pump to neaten things up.

However, the facet pump makes a racket - not keen on the clunking sound, which in itself goes away when the TDI makes way more noise - but as I listen to AM radio all the time, the clicking interference when near buildings and bridges is really annoying. So I'm going to mount it on the chassis down the line a bit, maybe even at the back just to get the thing away from the radio.

One thing with this though - Dave, you say that a relay may be needed for this location, is it because of the voltage drop for the distance? Have no issue with installing a relay, but is it really necessary for a small motor like this? Thanks, Simon

I put it in for 2 reasons

1. voltage drop
2. it allows you to fit a fuse and warning light so that in the event of a wiring short you get an indication as to why it stopped and what parts caused the stoppage.

the clicking interference may not go away just by relocating the pump and adding a relay, you may also need to add a Choke and a small capacitor between the power supply and the pump.

I personally like the clacking noise just prior to start up as it gives you a warning about a fuel leak. If when you turn the key it rattles differently than normal then somethings changed and you're loosing fuel out of the system somewhere OR somethings blocking up depending on how the rattle changes.

Dave. Thanks for the info. I will relocate first with a relay and see what happens, can install a capacitor if needed later. Sorry to be uninformed but not sure what a Choke is.

thats easy, thats why theres no limits on the questions your allowed to ask.

A choke is essentially a ferrite bead or ring with a bunch of windings wrapped around it that aids in suppressing electrical noise. Jaycar has them so should any good auto audio shop.

Is there any advantage to installing an electronic pump other than to remove the original mechanical pump which is prone to leaking fuel?

Thanks,
James.