Peugeot 806 2.0i turbo (Xu10J2TE) - died while driving, wont start, no gasoline, no spark

[ekjdm14]

Ah this is a good sign, yes I'd first go over the connections to the relay & make sure all is good there. (I've seen a few instances on this era PSA cars where the connector itself is OK but the wire is corroded/broken internally just where it goes into the crimp, so bear that in mind.) Then, assuming still no start once the connections are verified good I'd suggest load testing the ECU powers/grounds with a headlamp bulb to confirm they're all capable of supporting current, and perhaps also load-test the fuel pump signal coming out of the ECU to confirm it's giving the "prime" command and is able to put out enough to trigger the relay (would use a 5w bulb there i think).

I have a feeling given what you've found though that the majority of the issue is going to be in the double relay or it's connections.

[tortuga]

OK, so there is a lot of progress today. I was able to start the engine!
I reviewed whole fuel feed, lowering the tank, taking out the pump, filter and disconnecting all the hoses.
The fuel filter was definitely clogged I was getting gasoline from the inlet part of the filter but there were only drops coming out on the outlet part. I have cleaned it with compressed air (blowing air from the outlet inside) and fuel started to flow although there is quite a bit of pressure in the hose between the pump and the filter, much more than in the pipe that goes from the filter to the fuel rail.
Tried to start the engine with the pump out in a bin with gasoline but the pump did not start at all, so I connected 12V+ to the pump directly it started and the fuel started to fill in the fuel rail. Once I primed the pump manually, I tried to start the engine supplying 12V+ to the pump by hand and the engine started. Interesting thing though, once primed the pump started automatically after I turned off the engine and turned the ignition on again.
Could it be that the computer is cutting off the pump if its working without gasoline to prevent pump damage?

I have ordered new fuel filter and now that I have the tank taken out I have cleaned it inside, just in case.
Also ordered new plug for double relay, to fix the problem with the socket (the outer shell is broken and is not letting the double relay to get deeper into the socket).

What happened (i think) is the following, when I was driving the engine stopped because of double relay plug failing. It cut off both fuel and spark. But then I was testing the fuel circuit manually and probably I have clogged the filter completely. It was probably obstructing the fuel flow before but it was still letting enough to get the engine running. But my tests clogged it totally (thats my guess), when I was running the pump manually for 20-30 seconds in a row etc. Now that I think about it, sometimes idle was running a little bit rough, just slightly, this would always disappear when accelerating up to 2000rpm. I have run the engine now without filter for a minute or so and I noticed the idle was perfectly smooth. This could well be first symptoms of fuel filter needing replacement.

In other words, I have solved the main problem when I removed the socket support and connected the double relay to the inner part of the plug directly (after that I was getting spark) but I couldnt start the engine because by then the filter was clogged.

Still the ECU is not replying but at least we know its working so it should reply. Probably bad connections between ECU and ODB socket?