306 HDI non start

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bobbydon8360
Posts: 3
Joined: 25 Apr 2025, 15:34

306 HDI non start

Unread post by bobbydon8360 »

Hi all,

I recently uncovered a 306 which had been parked for around 10 years, so far I’ve managed to recover it and get it turning over and briefly running under the influence of easy start, however I can not get the car to stay running for more than around 10 seconds, when I plug in my diagnostic tool (launch) it reads that the ecu is not communicating, I have checked the connectors going to the ecu and there is no corrosion, fuel is pumping to the rail however I also believe there is not enough pressure to sustain the engine. Any ideas on how to sort it much appreciated.

Thanks
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mickthemaverick
Moderating Team
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Joined: 11 May 2019, 17:56
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Re: 306 HDI non start

Unread post by mickthemaverick »

You need to get a diagbox on it and see what live data you are seeing with regard to fuel pressure as a start. :)
I used to be indecisive, now I'm not so sure!
I used to ride on two wheels, but now I need all four!
PaulC5
Donor 2024
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Joined: 06 Jun 2023, 15:26
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Re: 306 HDI non start

Unread post by PaulC5 »

If it has an immobiliser then possibly the key is not being recognised. If you leave the key in the ignition and open the driver's door do you get a warning, if not it might suggest the key is not recognised.
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Oldpug
Posts: 558
Joined: 07 Aug 2010, 11:15
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Re: 306 HDI non start

Unread post by Oldpug »

I agree to both the posts above. Find an “old school” Peugeot specialist who has the Diagbox and the old diag2000, and has experience with these old Peugeots.
Obviously the battery has been replaced, that has probably triggered the immobiliser. Also are you sure the key is the original one and the chip inside is intact.
As it’s been stood for over ten years there could be other problems? Mainly poor wires, green corroded connections, bad earths etc.
Best of luck, that 306 would be a good car to restore. ( Last of the real Peugeots ).
Uberderv
Posts: 20
Joined: 01 Jun 2014, 10:47
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Re: 306 HDI non start

Unread post by Uberderv »

bobbydon8360 wrote: 05 Sep 2025, 20:32 Hi all,

I recently uncovered a 306 which had been parked for around 10 years, so far I’ve managed to recover it and get it turning over and briefly running under the influence of easy start, however I can not get the car to stay running for more than around 10 seconds, when I plug in my diagnostic tool (launch) it reads that the ecu is not communicating, I have checked the connectors going to the ecu and there is no corrosion, fuel is pumping to the rail however I also believe there is not enough pressure to sustain the engine. Any ideas on how to sort it much appreciated.

Thanks
There are only a handful of situations which prevent the engine from starting. Off the top of my head its cranking speed, immo, fuel pressure and cam/crank synchronisation.

After ten years of sitting idle I'd check cranking fuel pressure as there is a spring loaded valve in the fuel pump inlet which can stick.