[AED]

I have a Rover 429sli(D). 1996. Had it about 3 weeks.
Found Bio Fuel (man says 50 per cent diesel and 50 per cent Bio is the mix). The last few days I notice that on ticking over or when changing gear there is a lot of smoke from the exhaust. It does not smell oily or anything and the car car runs as well as it always has done. Any help would be welcome as to what the cause of the smoke is as it is a lot.
I have just gone back to diesel.

[E_T_V]

What colour is the smoke?

Have you tried unplugging the vacuum supply to the EGR valve and plugging the loose end of the pipe to eliminate the EGR as a possible cause.

[AED]

Light grey. I do not know what the EGR valve is

[E_T_V]

If it is light grey and smells of diesel or chip fat then that indicates injector problems or incorrect fuel pump timing (the latter usually gives poor starting and performance though)

The EGR valve is the brass mushroom shaped thing at the back of the engine with a thin black vacuum pipe going to it. Remove this pipe and plug the free end of it. (the one in this picture has already been disconnected).

[AED]

I will try plugging the pipe and thank you for the picture as it explains a lot. Also I will get some injector cleaner. Do you think the bio fuel was the problem then. Luckily I have not put more than 2 full tanks in.
Should I change the fuel filter. Many thanks for your help.

[AED]

Today I removed the tube from the EGR valve and sealed the tube off. I have also filled up with diesel and put Redex in. I have just changed the fuel filter and when it gets dark I will take the car for at least an hour's run along the motorway. After that I do not have any ideas.
Anyone tell me what has happened and the chances of success.
Thanks