[Engine] Low revs and Blue/Grey smoke 2.0HDI

[Agri_Yuppie]

Help !!!
My 52 Reg 2.0 HDI is causing me to tear my hair out, She starts fine but she wont go above 1200 revs. as you put your foot down, she runs lumpy and emits a Blue/Grey Cloud of smoke. The smell of the smoke is partially burnt Diesel. She is not using oil.
She was showing the temperature gauge in the red and flashing stop light on start up (Temp sensor ??)
I called out the AA, He hooked his code reader up and it threw up temp sensor fault and Mass airflow sensor. He was able to delete these fault codes, but was unable to get a live readings feed with the engine running.
 So was unable to clarify the problem. Potential causes so far are: Injector fault. ECU Problem or Mass air flow sensor fault. It seems to be getting an incorrect ratio of fuel and air.
Before i start spending, Any Ideas Please

[Col]

Try disconnecting MAF. If it runs OK with it disconncted. you have proved it was at fault.

[ffrenchie]

Stop calling it "she" and it will be a lot less temperamental

[Agri_Yuppie]

Well yes you could be right ffrenchie. I must admit all the vehicles and machines I have ever owned or driven are certainly referred to as "She"
For various reasons !!

[Agri_Yuppie]

Well today I made a major discovery, After taking the battery, battery box off  etc and checking various electrical connectors. While reassembling I forgot to push the two vacuum pipes back onto the EGR solenoid valve, that is bolted onto the Battery box. When I started her up, she would run and rev as normal. She was  still a bit smokey, but it cleared as she burnt the excess Diesel that was still in the cylinders.
I have had the EGR valve removed and the pipes blanked off a year ago. So was surprised that this part is giving trouble.
Obviously the function of this Solenoid valve is to control the vacuum that comes from one of the pipes, to the other which seems to open a valve when you suck on the pipe.
Do I need to replace this valve or could I get away with joining the two pipes together and leaving the electrical connector on the old valve.

[Agri_Yuppie]

After a bit of internet research, it appears the vacuum solenoid could be related to the turbo ??

[Col]

Boost control valve would cause loss of power. It's at the front of engine down low on a bracket.
There was another post about it somewhere and that had pics.

[Agri_Yuppie]

Hi Folks,
Just an update on the story, It turned out to be the EGR Vacuum solenoid, That was causing all the problems. I tried plugging the two pipes together, but that just caused the same symptons. So i left the electrical connector  and the pipe which is on the suction side, on the solenoid (I was advised it needs to be blocked off to provide the brake servo Vacuum). The other pipe is unplugged and  pointing upwards. She starts well and does everything as she should. She went for a MOT and I did wonder about the emissions test, but she passed fine.

I am not sure if it was related to the EGR Solenoid or the Mass air flow sensor, that I changed. But the engine is far more responsive than it had been for a long while. I can accelerate up hills again, instead of dropping down the gearbox, while still loosing speed