[Engine] Purge Valve

[Landmark]

Hi Folks,
Trying to get to the bottom of black soot out of the exhaust i.e running rich on start up. Done the usual - air filter/cleaned MAP sensor & breather pipes/ injector cleaner but was wondering if it could be a faulty purge valve i.e letting dirty air into the combustion process on cold startup. I know it allows recirculated gases through when hot but is there any way of checking it please.
1.4 petrol Berlingo Multispace with 115k on clock and original valve (& MOT due!!)

Cheers,
Griff

[geoff]

^^^^ Looks like another poxy spammer !!