Boost won't Exceed 7-8 PSI

[SHOFox29]

Hello SHO Forums! So I have a Stock 2010 Sho PP 106k Miles. My baby won't make above 7-8 at any RPM at any Speed. Many many things have been replaced all within the last 6 months by the dealer and myself.
By dealer:
Used engine with 85k miles(will include internal pics if I can)
All VVT Solenoids
All Plugs
All Ignition coils
Both Exhaust Flex pipes
Front turbo
All turbo oil lines
By me:
160⁰ Thermostat
Knock Sensor
Both Camshaft Position Sensors
MAP Sensor
Boost Solenoid
All Intake manifold gaskets
Valve cover gaskets
Many misc orings and seals related to intake manifold and valve cover
__Intake Valve cleaning job__

The car runs very well. No misfire, no studder, feels powerful but its not all quite there. Ive inspected all charge pipes and the clamps are tight. BOVs are clean and diaphragm is not torn. Took off rear catalytic converter and the exhaust inpeller on the rear turbo looks good and little to no play, wastegate flap is sealed strong. Im moments away from putting on a new rear turbo but I want to make sure im not missing anything and wasting my money and time. Thanks so much for any help!

 

[SM105K]

Have you checked the charge piping for cracks? The rear charge piping has been know to come apart near the turbo. Have you checked the intercooler for leaks as well? What about the noisemaker? They are known to leak under boost.

 

[Ecoboost_xsport]

Stock turbos still? Stock wastegatr spring is about 3-4psi, but ATP turbos have a 7-8psi spring....

Or it could be the boost solenoid is going out as well.

 

[SHOFox29]

Have you checked the charge piping for cracks? The rear charge piping has been know to come apart near the turbo. Have you checked the intercooler for leaks as well? What about the noisemaker? They are known to leak under boost.

Yes, charge pipes are all good, I've removed them all and cleaned them well. At one point I took off the noisemaker and put a plug in place because I was worried about boost leaks through there and saw no difference so I put it back on.

Stock turbos still? Stock wastegatr spring is about 3-4psi, but ATP turbos have a 7-8psi spring....

Or it could be the boost solenoid is going out as well.

100% stock, brand new OEM boost solenoid as stated in OP. The wastegate was concern as I swear I could hear it clacking and open/closing quickly at high load but when I took the catalytic converter off, the waste gate flap was still firmly clamped and didn't seem like it would be leaking or loose.

 

[doit221]

Yes, charge pipes are all good, I've removed them all and cleaned them well. At one point I took off the noisemaker and put a plug in place because I was worried about boost leaks through there and saw no difference so I put it back on.

100% stock, brand new OEM boost solenoid as stated in OP. The wastegate was concern as I swear I could hear it clacking and open/closing quickly at high load but when I took the catalytic converter off, the waste gate flap was still firmly clamped and didn't seem like it would be leaking or loose.

What about the actual pipe from the throttle body to the intercooler where the noise maker mounts to? The plastic hose clamps on them are junk and sometimes the pipe itself can get loose. I ended up replacing mine with the noise maker delete.

 

[bpd1151]

I am confident it is the diaphragm on one, or both of the electric bov's.

Remove them (the entire bov) from the piping, then extract or pull on the center plunger gently and inspect the rubber portion (should be orange in color, but could be another).

If you notice even the slightest of a tear, that'll be your culprit.

The only other issue I could think of (which that model year was prone to) the dreaded chafing of the knock sensor wires / wire loom.

Report back your findings and good luck.

 

[SM105K]

What are the stock boost levels?

 

[Ecoboost_xsport]

What are the stock boost levels?

Around 11-12

 

[SHOFox29]

I am confident it is the diaphragm on one, or both of the electric bov's.

Remove them (the entire bov) from the piping, then extract or pull on the center plunger gently and inspect the rubber portion (should be orange in color, but could be another).

If you notice even the slightest of a tear, that'll be your culprit.

The only other issue I could think of (which that model year was prone to) the dreaded chafing of the knock sensor wires / wire loom.

Report back your findings and good luck.

As a long time lurker, im happy to have your help =) I've inspected them before and thought it looked fine but perhaps im mistaken? Ive already replace the knock sensor, it was in fact chaffed.

 

[SHOFox29]

What are the stock boost levels?

Around 11-12

Yes, this is the number I used to see.

 

[SHOFox29]

Addition bov pic

 

[SHOFox29]

I just took off and inspected the other one too, they both look fine and identical.

 

[jasong_10]

You mentioned changing the MAP sensor, which one did you replace? There are (2) indentical looking sensors, (1) on the intake, and one on the intake tube near the noisemaker.

 

[Quimicax]

You Have P0299 In OBD2 Codes?