I have a 99 306 hdi and have possibly currently got the same problem except mine can take 2 hrs or more before it will start. It's happened 4 or 5 times over the last 3 or 4 months
today I had to sit in a car park in sweltering heat for 3 hrs, not nice
quite often you think it is going to fire but it just stops then just turns without seemingly trying to fire, then if you leave it 30 mins or so you think it's going to start then just goes back to turning over again
I've just had mine diagnosed today by the aa of needing a new multi function relay valve as pin 9 has burnt out, apparently a common problem with the 306, so possibly the 406 too? on mine the plug is on the passenger side, close to the bulkhead. by wiggling the wires the aa bloke managed to get the burnt pin to connect and it started. mine's booked in with an auto electrician tomorrow
i'm no mechanic but apparently it runs the fuel pump situated on the petrol tank
another common problem with my model is apparently if you leave the car on an incline facing downhill, the fuel can run away and the guages are not very true reading so it thinks the tank is empty, although i've never experienced this
>> Stay informed about: 406 HDI starting problem (1999)