not boosting over 10psi???

[wicked98gsx]

Ill get straight to the issue... I installed a MBC a few months ago and had issues with the I/C pipes staying together.... problem fixed and now No matter how much I turn my MBC... the psi wont go above 10psi..... I turned it down to 0(zero) and adjusted it after each pull. My MBc bumps up +2 each click. Im now up to 6 clicks (12psi) and its not boosting at that... only to 10psi and thats it. Now maybe I read a thread wrong but I removed the smaller spring from my GReddy BOV cause Im getting compressor surge also still and I set it like multiple evo and DSM forums tell me to.


I have no boost leak and my piping has been tested up to 35psi. Someone point me in a new direction.

 

[Spanky_DSM]

have you checked your wastegate?
disconnect your waste gate line and see if it builds boost, just make sure you dont over boost it, just enough to verify it does build boost and if it does, most likely its opening prematurely.

 

[PrimerPLus]

Do you have your MBC hooked up correctly? What MBC do you have?

How did you test for boost leaks? Did you leave your MBC hooked up during the BLT?

 

[WES_393]

the psi wont go above 10psi..... I turned it down to 0(zero) and adjusted it after each pull. My MBc bumps up +2 each click. Im now up to 6 clicks (12psi) and its not boosting at that

Your MBC by itself should not be able to turn the boost to zero. The way MBC's work physically won't allow you to boost lower than wastegate pressure. So I'd suspect issues with the wastegate, actuator, or actuator arm. Hook a boost line straight to the actuator and see how much boost your making. Then remove the actuator arm and make sure the wastegate flapper isn't sticking or sitting slightly open.

 

[wicked98gsx]

have you checked your wastegate?
disconnect your waste gate line and see if it builds boost, just make sure you dont over boost it, just enough to verify it does build boost and if it does, most likely its opening prematurely.

If I unhook the wastegate line... it hit damn near 22psi fast(as in soon as it starts to spool... it hits 22psi)


Not sure what MBC I have but you bring up a valid point... Im probably about to feel dumb as f**k but pressure from the I/C pipes is supposed to blow into/towards the wastegate actuator....right? WTF

Your MBC by itself should not be able to turn the boost to zero. The way MBC's work physically won't allow you to boost lower than wastegate pressure. So I'd suspect issues with the wastegate, actuator, or actuator arm. Hook a boost line straight to the actuator and see how much boost your making. Then remove the actuator arm and make sure the wastegate flapper isn't sticking or sitting slightly open.

you posted while I was replying... like i said above.... if i unhook it the it boost high... but I was able to turn it to zero so now im concerned. hooked straight to the actuator then it boost at 8psi every pull

 

[WES_393]

Then I would try hooking it up differently. If it's backwards I suppose the ball and spring could keep the wastegate actuator pressurized which would keep the flapper open.

 

[wicked98gsx]

Then I would try hooking it up differently. If it's backwards I suppose the ball and spring could keep the wastegate actuator pressurized which would keep the flapper open.

Could this also cause the fluttering sound that im still getting from the turbo when of let off the throttle after boosting?

 

[PrimerPLus]

That fluttering noise it coming from your blow off valve.

Was your MBC set up correctly?

 

[wicked98gsx]

es the BOV was hooked up correctly. And im very certain that the fluttering sound is NOT my BOV... it is not recirculated and I can hear two distinct sounds.... I replaced the BOV gasket yesterday( it was baked on the valve flange ) And I replaced a coupler that I found had a few very small cracks on the underside of it.


Now when I say a distinct sound.... My BOV chirps very loud.... but im also hearing a "ch-ch-ch-ch" sound coming from the filter and like I said... Im vented, not recirculated. But I set the BOV like I've read... loosen it till I start to hear a hissing sound then tighten it 1 full turn and I also removed the small spring and just left the big one in it. I have 0 shaft play so I just want to fix this issue also..



Oh and I think the coupler and gasket were my boosting issues.... Im back up to 12psi now.

 

[asianandy87]

Check the spring in the wastegate, or maybe your vacuum lines, or if you have a boost controller it could be bad.
Keep running over the intercooler piping, or get a boost leak tester.
check your throttle body and sensors on the throttle body.

 

[wicked98gsx]

Check the spring in the wastegate, or maybe your vacuum lines, or if you have a boost controller it could be bad.
Keep running over the intercooler piping, or get a boost leak tester.
check your throttle body and sensors on the throttle body.

Im going to assume the wastegate spring is fine cause right now it's plugged directly into the I/C piping and im boosting at 8psi. I think the MBC was bad cause no matter how much I opened it up... it wasn't getting over 10. I BLT'd the piping like im supposed to and my piping is holding psi. One thing I noticed.... When I would really push the car, It would buck and jerk hard but pick right back up and haul a**. My coil pack that controls cylinder 4 & 1 was spazzing out. Could this be what could have been causing the psi not to rise up any higher?