Possible turbo / boost problem??

Hi all I have a d40 2007 Spain build I have had a boost gauge fitted to it over a year ago, within the last month I have noticed on the gauge it's boosting up slower than what it used to? Max boost has always been around 20psi and it still hits that mark but a lot slower I feel. There's not a massive power loss but I do believe it's not the same as what it used to be. I have checked boost/vacuum lines and no splits right through. Maf sensor is clean. It has 169000kms on the clock could it be possible the turbo is knackered? Cheers.

check for a vacuum leak, - i have an 07 RX and changed all the vacuum lines, and it made a difference for me, cheap and easy, lol

vacuum lines cost less than 5 bucks from super cheap, they have it in bulk, i got 3 meters of the smaller stuff (if you have cruise control it may cost more as the throttle body actuator runs on vacuum, think about double the amount) from memory it is mostly the 3 mm stuff, but i would check

also remove and clean the maf sensor - i use electrical contact cleaner,

clean the turbo control solenoid (lives near the air filter, all the vacuum lines go through it) - i use electrical contact cleaner, magic stuff

then there's the SCV that may need a clean/replacement, i haven't had to do one of those yet so i'm not too sure about how long it takes, or cost, but reading on the forum its a couple beer job, (it lives on the back of the vacuum pump) evidently cleaning in diesel is the way to go with this

if everything on the vacuum control side checks out then there's possibility that the egr is not blocked and possible stuck open (robbing exhaust to spin turbo up quickly) - if you haven't blanked this i highly recommend it, made a huge difference in throttle response to mine when i did it, - also look for exhaust leaks pre turbo while lookin at all this

another thing that may sound completely unrelated but i was surprised what it did to mine, was look at when the last time your fuel filter was changed, over time it blocks up and turns into a fuel line restrictor - mine got so bad that the engine would actually miss and throw fault codes under heavy acceleration due to fuel starvation


im sure there will be lots more advice on this as well

remember always try the simple easy stuff first, cause it usually doesn't cost alot of money

Slow boost could be vac leaks but there's also the solenoid - which might be failing or may just have an electrical gremlin in its connector. There's also the possibility that the turbo vanes are sticking, or the vac diaphragm in the turbo actuator has a leak. Sticky vanes should be really obvious with a cold engine - tomorrow morning, pop the bonnet before starting and get someone to crank the engine over. Shine a torch under the actuator - it should be moving freely at idle, immediately after start. If it's not, chances are your vanes need attention - unfortunately that means a turbo rebuild, but thankfully a seal set on eBay is only around a couple of hundred $.

The SCV having problems is a distinct possibility at that age and fuel system cleaner does sometimes work wonders, but it shouldn't impact on boost pressures or the rate of boost rising.

Things that do affect boost rates are the MAFS, actuator, vac solenoid, boost pressure sensor (low on the right-hand side of the intercooler), charge air hose ballooning/leaking, EGR tube leaks. Look around the engine bay for sprays of black oil, particularly around the joins of the large hoses coming off the turbocharger outlet and from the intercooler to inlet manifold. Remove the top cover of the engine and examine the gold tube that runs around the front, looking for black soot expelled from a crack.

Ok will have a look at everything you guys have mentioned I appreciate the detailed replies cheers