Hello,

I have Focus ST '06 with modification and I have boost problems. I dont have problem that I have always 1/4 of boost, but I dont have proper full boost as I shound have.
Also time to time its like.. its going to boost and then pressure wave around 1/4 of boost (you feel like car is not pushing constantly) and then continue into 3/4. With my Dreamscience ECU map I always had 4/4 of boost.
Boost seems to me also very slow... Turbo lag takes longer than before.

I once had problem with oil housing so I replaced it for new with breath pipe too.
Now I hear just a very little whistle from oil housing... not like when I had problem. Is there possibility that its faulted just a very little?

Or it can be problem with Boost solenoid? Is problem with solenoid shown on diagnostic as fault?

Thanks for help

 

The boost solenoid is a very common failure.

 

Is boost solenoid issue showing on diagnostic or not? I read error codes and its clean. No fault.

 

Is there any vacuum pulling on the oil dip stick?
There shouldn't be any, otherwise maybe you still have oil filter housing issues.

Boost solenoids are very common problems.

 

I tried pull oil stick but no vacuum. I ordered new MAP sensor and boost solenoid, so I will see if it helps.
I will also remove symposer and blank it's hose to prevent any boost leak.

 

Im having these same turbo boost issues with mine, especially in the lower gears, put a new boost solenoid on today and made no difference! When I take the oil cap off I do get suction noise and with the dipstick, do I need to replace my oil filter housing then people???

 

Yes, if you have vacuum under oil cap or oil stick, then fault is in oil housing. There is small rubber diaphram which is damaged, air is going through and creating this vacuum and typical whistle sound when cap is closed.
Only way how to solve is replace whole oil housing which you can order from Volvo too.

 

Thanks for the reply, put a new oil filter housing on today and its boosting alot better but still not feeling like im getting all the boost my gauge indicates! So thats a new boost solenoid and a new oil filter housing, gonna try having a pressure test on the air system next to check for boost leaks. Is there any other common problems on the ST that I should check for regarding boost issues guys? Cheers

 

Maybe MAF or MAP sensor. Did you tried diagnostic if any fault codes appear?

 

Gonna replace maf sensor and map sensor next so at least that's 4 of the most common problems covered and maybe then I will have the performance I should be getting! lol. Thanks for help and info its much appreciated.

 

I already had theese problems once, so I replaced solenoid... nothing. MAF helped, but it showed on gauges as ESP SYSTEM FAULT and in diagnostic software too.

Then I got issue with oil housing (typical whistle and vacuum under oil cap). Replaced. Fixed.

Now I have again issue with boost. Gonna try replace solenoid and MAP and will see. I dont have any engine light, ESP light... or any other error.
I update info here after replacement will be done.