Lack of boost

[ajc106]

Hi gents just a quick one as title says lack of boost has been fine over half way into the white then on way home from work yesterday stop going into the white altogether have changed the bcs this morning and checked all the vac pipes all seem fine but no change any ideas please

[deathrider311271]

weak actuator

[JamesT5]

MAF sensor could be at fault, the ecu will prevent boost because the MAF isn't telling the ecu how much air is coming in to the engine.

[hybriduno]

MAF sensor could be at fault, the ecu will prevent boost because the MAF isn't telling the ecu how much air is coming in to the engine.

this is another factor, there are a few sensors that would throw up an error like james says, maf scaling would screw it all up. but also actuator would too as deathrider has stated.

[graemewelch]

get your codes read. guess work is pointless. itll cost you more in the long run

[merc85]

could be maf, disconnect the vac tube to the turbo actuator the car should boost and boost. be careful not to much for obvious reasons.

if things don't change it wont be the actuator

Sometimes a bad maf wont throw a light, had this on mine once.

[ajc106]

thanks gents turbo was refurbed in the summer so will take a look at the maf have a spare so will try that tomorrow

[ajc106]

might also have a fault on the chipped ecu as i put the standard one back in and it seams to boost a bit better than the chipped one

[850 T5s]

my 2003 d5 done the same the other week, the fault logged was the boost control solenoid, cleared the fault and its been no bother since

[ajc106]

latest update have just put the chipped ecu back in and the boost is back to where it was before so will have to wait and see if it happens again thanks for the advice as always guys