EFI fuel pump failure

[silverbullet]

Still trying to diagnose a leak-down fault on wbx(6) with EV14 injectors from Injector Rehab.
Its had two fuel regulator swaps now, seems to need a lot of priming pulses and still takes 3 or 4 cranking sessions to get it to splutter into life.
New Bosch pump fitted right from the installation of the fresh engine but was breifly subject to reversed connections (duh!) on initial fitting so have I fragged the pump?

[TwinTurbo]

Pull the feed off and see what the flow is like at the rail.  If you can get one a presure guage and see what and how quickly the presure gets up to the required level probably arround 3bar for most EFI systems. 

I don't think reverse polarity will have casued any damage unless it's jammed a flow valve. 

[silverbullet]

The valve inside the pump is my worry, never had one that behaved like this. Having two failed fuel regulators in a row - petrol seeping out the vacuum connection - was also a bit of bad luck.
Naturally all the hoses are secured with Oetiker clamps so thats a PITA...

[TwinTurbo]

Take an injector out instead then and see if you get flow straight away. 

Has it run since the rebuild? have you checked the compression and static timing on the "fresh engine" 

[silverbullet]

I let it stand for a few days and tried it today. Still need loads of repeated cranking (fuel pump running) so I reckon the pump is duff or damaged and not maintaining fuel rail pressure at all.
Usually any wbx will hold its fuel rail pressure for months, this can't hold it for a few seconds.
It was running quite well before the last fuel reg failed, basic ignition timing isn't far off but it didn't like a rapid change in throttle opening and if it closed suddenly it would also tend to stall.

[TwinTurbo]

clamp the return, that FPR may be faulty again

[silverbullet]

Three in a row? Even my luck isn't that bad!

I tested them all with an airline and they all blow off at 2.5 bar which is correct, no leakage to the vacuum side.

I'll try clamping the return and report back.