306 XS 2.0 HDi died suddenly not starting anymore

[TheMailPilot]

So, i'm new here.. had been a member before but cant remeber.  .

So this happend on my old pal..

I drive a 306 XS 2.0 HDi and i did already 510,000kms with no severe problems, and i still love it.

But last week it suddenly died whilst driving.

First some things..

- i noticed a week or two before that i sometimes had loss of power when i didn't start with throttle fully open. And i suspected a sticky egr valve. Especially in the cold from now. 

- after the motor dying i rapidly found a parking spot in the city. Then had a few minutes to check.. i heard no lp pump at ignition turning on (changed already that one two years ago) so i already know that problem. Aha no fuel delivery,.. thought maybe again a lp pump..
But most likely first checked if it even received power... And results was no... What it noticee was that when ignition was on some relays we're acting strange under the hood.. (which made me almost cry, because i know thats the place where the ecu is) not giving any attention to that at the moment, put 12v directly to the lp pump, it runs but the engine won't start.. so something is blocking it to give it through. As there is no receiving power to the lp pump theres only the way back and thats ?? Already changed the fuel pump relay (brown sealed) at the ecu box without result, only no ticking relays anymore now... what could be another option

[C2K]

If your relay and pump are working, then you have an issue with rail pressure. The relay is the only thing, short of a broken wire, that would stop 12v arriving for the pump to run on a healthy relay. It’s not very clear if your pump works with the new relay.

Regulator or pressure sensor, maybe hp pump. There is a guide on here somewhere about eliminating them, think poodle wrote it. Get it on Peugeot planet for Codes and measurements.

[TheMailPilot]

After the new relay installed all still the same. No 12v to the lp pump...

(I picked an external 12v battery and directly put it on the lp pump and tried to start the car that way but also no luck starting)

Are there any fuses that i should check ? 
I suppose that when i get 12v running to the lp pump all should be fine, as the diying happend when i was doing 70km/h i did not stall or humped.. just tick engine off... 

What logic has to happen to get 12v to the lp pump.. the problem is between the battery and the lp pump... 

I was thinking 

- Loss of keycode
- Crash-switch activated (dont know how it supppse to feel when reset, can this be bypassed for testing ?)
- Ecu fried
- ???

I still wonder what happend with all te ticking of the relays after engine dying...

[FuST]

Just a couple of ideas, might not be useful (or coherent for that matter )

To my knowledge a loss of keycode should not interfere with the lp pump, the immobiliser merely shuts off the injectors.
I don't recall off the top of my hat wheter the 306 has a pressure sensor on the lp system (don't have my Haynes or Autodata handy atm), but with my HDi I can hear the lp pump whizzing whenever I turn on the ignition regardless of how many times I do that.

One really simple way of testing the lp system is to disconnect a fuel line under the bonnet (before or after the filter, just make sure not to get any crud into the lines), put the end in a container and see if fuel gets pumped through when you turn on the ignition or manually power the pump.
Might be a blockage of some sort, or maybe the lp pump is simply not getting enough fuel to the hp pump. Might even be water in the fuel filter (seems unlikely to me).
Just because the lp pump was replaced 2 years ago doesn't mean it can't be at fault (rule #1 of problem solving: don't rule anything out )

Edit: also check the fuse for the lp pump, it's #35 under the bonnet iirc. You should also be able to feel the relays behind the ecu click when you turn on the ignition.

[TheMailPilot]

Yess indeed, but theres no 12v coming to the lp pump.. so the pump must be outruled for the moment.. how come does the 12v not being supplied to the lp pump, wich masters that...

---

I'll have a look to that fuse, is that the small black box with a lid, next to the battery ?, I'll have feel tomorrow aft of the ecu.. i'm sorry if my english isn't that good btw

When the relays we're flipping i felt al those relays clicking , i've put my hand on it that moment to give a quack :/. After installing the new fuel relay they didn't flip anymore so to my feeling or there is a small thing i oversee or theres stuff broken during install i had to bent the backplate of the ecu mount to get the fuel relay out. And heck my fingers almost frozen off in this temp outside... (No garage at house)

[FuST]

The lp pump is controller by the ECU. It switches the brown or black relay behind the ECU on when the ignition is turned on and switches off after about 6 seconds. Also, fuse #35 (I beleive) under the bonnet is for the 12v supply to the lp pump.
If the relay clicks and the fuse is okay (measure it, don't eyeball it), check that 12v is getting to the pump (use a lightbulb on the 2 thick wires, the thin ones are for the fuel level sensor)
If the relay doesn't click reset the crash switch.

Failing that, get the codes read with a PP2000 and see what the ECU tells you.

[TheMailPilot]

Yes i'm measuring everything, thats why im sure the lp pump doesn't receive anything. Tonight i will look/feel the relays... I asked a formerly peugeot technician to have a look and bring his material to read the ecu..

How can the crash sensor be tested or bypassed ?
Thx for the co-thinking guys, together to the solution. Also informed for a new ecu.. 1249€ crazy bastards

[FuST]

The inertia switch reset (under the bonnet) is just a 2 pin switch, it can be tested with a multimeter or bypassed with a jumper wire (pins 1 & 3 on the plug I beleive, check the terminals on the switch to be sure). I'm not sure about the inertia switch itself.