03 Evo 8 won't boost past 10psi, help!!
 

EDIT: Problem has been solved! Thanks to everyone who pitched in!

boost leak test

chances are you're just running off the wastegate pressure and your boost controller isn't doing anything (i.e. it's just letting air flow through it freely and not regulating it)

Demon is right about the BLT being the first step.

Def prob a boost leak from what it sounds like. I check for them once a month at least! Best of luck resolving the issue.

Thanks for the quick replies, guys. I'll be conducting a leak test asap. I forgot to mention that this occurred while I was driving the car rather lightly. I barely gave it any throttle at all and while putting it into third I let it creep up to boost and the turbo basically surged on me. My original thought was that one of the clamps or couplers gave out so that makes sense to me. Will update after boost leak test!

How are you controlling boost anyway?

The car was previously modded when I bought it. It's got a Hallman MBC.

So, have you tried adjusting the boost higher with your MBC, and it just wont go up past 10#???

Precisely. I tried turning it up yesterday to no avail. It just cuts out at 10 pounds. It like chokes the car and I get a bit of backfire. Still think it's a leak?

EDIT: I could add a couple of videos this afternoon if that would help explain the situation.

When I buy a used turbocharged vehicle, the first thing that I do is replace both of the MBC's existing vacuum hoses with new 4mm rubber hose. I secure the fittings with 1/4" hose clamps as I don't trust nylon zipties myself.

It could be a leak. But, to limit boost to 10# it would have to be a humongus leak indeed. Get down underneath and check the two connector hoses from the IC inlet and outlet to the intercooler pipes.

I hear ya, it's just strange because I've owned the car for almost two years now. The day after I bought it I took it to Mach V in Sterling, VA and they said it was one of the most solid 03's they'd seen in a while. You think I should go for the hoses first or test for leaks?

EDIT: Sorry, just read your post. I'll look into it as soon as I get home and update. Thanks for all the help, man.

Sometimes the vacuum tubing that connects to the nipple on the backside of your boost gauge can pop off, or the tubing can be punctured somewhere along its trajectory along the firewall or elsewhere in the engine bay.

Yes. Have you done one since you bought the car?

Nope, I know I should regularly but I just haven't. I used to do them all the time on the ol' DSM. I guess it's back to square one then I'll move from there. Thanks guys