Peugeot 406 hdi 90

Join the club. You are not the first. The same thing happened to me and Peugeot's answer is to replace everything from the tank to the injectors at a price (quoted by my local dealer two years ago when mine went) of £3,500. In the event a local mechanic did it by cleaning rather than replacing and I was fortunate that the particles had not got past the filter. That cost me £800. Other people on this group have had the same problem, it seems to be an HDI thing. Mine was 5 years old and at 92,000 miles so I could not really complain but since then I have seen people at under 30,000 some have even been early enough to be done under warranty.

It is a fault in the fuel lift pump in the tank. The bearings were clearly badly designed, and you get little bits of bearing metal getting into the fuel system. How these get through the fuel filter, I do not know, but if they do then they can damage the high pressure pump, and even the injectors. So the only safe way to deal with this is to replace the lot, though it might be possible to strip and clean components, and just replace the lift pump. I hope they have redesigned the lift pump by now, so a replacement should be more reliable. (I have a 307 HDI, which is so far OK).