3.5 hot wire efi suddenly not starting

Got in, fired up and ran for a few seconds then dies; no sound from fuel pump. Thought it might be the connector to the pump which has a habit of coming loose but pressing/moving/twiddling it didn't make it come on again.
Tried to start and got lots of chattering and what's sounded like shorting noises (no smoke!) coming from the relays which are on the bulkhead wall engine side. Took out fuel and main relays cleaned terminals and replaced but still not firing, fuel pump o/s and chattering from relays.
Did wade through a flooded bit of road the other day but has been working ok until this afternoon. `damp ingress somewhere?
Have had some issues with the fuel pump, either the plug comes loose and couple of weeks ago it stopped whilst driving but started up again with some effort. If it's gone/going would the relays freak out or just no fuel supply?

A job for tomorrow.

Had two fuel pump incidents on my flapper.
1. was failed pump. Had been noisy & then just stopped working.
2. was feed wire corrosion a couple of inches up the main loom live from the connector (r/n/s wheelarch on mine on top of the chassis)
Neither caused any issues other than no fuel delivery.
Hopefully your guess of water ingress causing a short will be correct. I'd part the connectors & blow out with an airline.

For both my 3.5 RR and now 3.9 D1 chattering relay sound and not turning over was down to the battery flat. Just my 2 pennies worth, but as u say a look-see is required. Starting with a 12v supply to the ign. coil.

discool said:

For both my 3.5 RR and now 3.9 D1 chattering relay sound and not turning over was down to the battery flat. Just my 2 pennies worth, but as u say a look-see is required. Starting with a 12v supply to the ign. coil.

Click to expand...

Thanks, that what I was thinking, perhaps just enough to start it initially....
I tried again with the headlights on, turned key and the lights went out and engine did not turn, even the relays stopped.
Weird, the inline voltmeter read normal and she's been fine until this afternoon.
I'll check the supply to the coil etc. and the battery and alt with the DVM.
Looks like rain all day tomorrow......might leave it until dryer.

As above, check fuel pump - ideally replace with Bosch 044 unit [if feeling plush plumb in two units in parallel] + do check coil for breakdown under load + distributor & amplifier

v8250 said:

As above, check fuel pump - ideally replace with Bosch 044 unit [if feeling plush plumb in two units in parallel] + do check coil for breakdown under load + distributor & amplifier

Click to expand...

Mine is an in-tank Range Rover efi pump modified to fit a Ninety tank.
Waiting for the rain to stop to go and check the battery etc.

cappers said:

I tried again with the headlights on, turned key and the lights went out and engine did not turn, even the relays stopped.
Weird, the inline voltmeter read normal and she's been fine until this afternoon.

Click to expand...

In that case I'd charge the battery with a battery charger & then see what happens.

Now working fine.
It was two things and pure coincidence..battery was fine.

1. Exciter wire to starter solenoid had worked lose yet again hence chattering relays etc; recrimped the spade but needs a locking one really.

2. In tank fuel pump electrics fine, took it out, rotor felt tight, tapped it and a tiny bit of grit fell out, powered up and pump runs again! All back in place with new pump gasket.

It conked out a few weeks ago whilst driving, no fuel pump. Thought wiring but thumping the tank got it going again. So that bit of crud was blocking the impeller. Filter was a bit grubby, can you renew the filter sock on RRC fuel pumps?

Fingers crossed all ok now.

cappers said:

Now working fine.
It was two things and pure coincidence..battery was fine.

1. Exciter wire to starter solenoid had worked lose yet again hence chattering relays etc; recrimped the spade but needs a locking one really.

2. In tank fuel pump electrics fine, took it out, rotor felt tight, tapped it and a tiny bit of grit fell out, powered up and pump runs again! All back in place with new pump gasket.

It conked out a few weeks ago whilst driving, no fuel pump. Thought wiring but thumping the tank got it going again. So that bit of crud was blocking the impeller. Filter was a bit grubby, can you renew the filter sock on RRC fuel pumps?

Fingers crossed all ok now.

Click to expand...

Every thing I can cross for you is…Crossed… also