1.5 dci 'foaming' fuel after filter.

[DaveyLC]

I've got a 05 1.5 dci which is have cold start problems and every now and then when its warm the SERVICE light flashes up with "Check Injection", When I look at the fuel lines with the engine running the fuel looks like foam, also when I squeeze the hand primer the fuel in the lines doesnt move.. If I remove either of the lines from the pump and cover it with my thumb the lines instantly fill with fuel.

It seems like I've got an air leak but there is nothing obvious going on

Any ideas?

[davelowe]

AlexB has previously mentioned that pin-hole (undetectable) sized holes can appear in the fuel lines. Since there is no fuel tank mounted pump (both low and high pressure systems are integrated), this means that the fuel lines are under negative pressure and so air can get into the system without any apparent leaks.

According to the Haynes manual, fuel is fed to the low pressure pump, through the filter, and back to the high pressure side before the common rail. So you may have an air leak, or the pump may be failing. My suggestion is that you design some experiment to narrow down the options. There may be a fuel diagram in one of the online pdf manuals in the links section that could help.