boost problem once again!

[218dsm]

can anyone out there tell me what im doing wrong? I just replaced my cracked up 14b with a ported one just til i get back on my feet but anyways...i put this new turbo on and it boosts fine and pulls hard but even with my m.b.c. the boost shoots past 20lbs....it hits fuel cut really bad and it boggs out when it goes past 20.....i dont have the mods for this much boost i know and im not trying to have that much...i had left the m.b.c alone since it was on the last wastegate...i called slowboy racing and told them how i had my vac lines ran and they said it was wrong but i have always ran that set up with no problem...so i changed it and still have the problem....i have a vac line from the wastegate to the m.b.c. then from that to the intake...and i have my b.o.v.. connected to the p on the throttle body....what am i doing wrong.....i think im going to switch the wastegates...i think this other one might be bad...

 

[92dsmtalon]

Check for boost/vac leaks. If you have a leak, that can cause your boost to spike.

 

[No_Skillz]

i have a vac line from the wastegate to the m.b.c. then from that to the intake...and i have my b.o.v.. connected to the p on the throttle body.

One of the lines needs to go to the wastegate. Make sure the other line that goes to the intake is somewhere that holds boost pressure (nipple on J-pipe is the norm with 14B). Also make sure the lines to the MBC are not swapped. What kind of MBC are you using?

 

[numlock666]

the nipple direct opposite from the adjusting screw on the mbc goes to the boost source (ie j-pipe) and the one that isnt goes to the wastegate actuator.

 

[SpeedJUnkyz]

I would remove the turbo pipes and wash them, then re check the routing of the MBC to ensure proper routing, be sure to clamp or ziptie them tight, Then also check the seals and gaskets on the turbo. Make sure all bolts and screws are snug. I would switch to t-clamps if you havent already. After buttoning everything back, run a boost leak test on it to make sure its not that. Ensure all clamps, bolts, screws or tight on the turbo/intake system.

 

[JDM_DSM]

You could also try making sure the wastegate is still functional by connecting a line directly from a boost source (I believe there should be one right after the turbo) to the wastegate with nothing in between. That should boost to about 9psi.
If that still surges really high then the wastegate is likely seized. Check that by disconnecting the rod from the actuator and trying to move the rod in and out. It should move freely.

 

[218dsm]

the wastegate is fine...the rod moves freely...i just dont understand why it would do this....it never did it before on my old turbo.....all my ic pipes are tight and there are no leaks....im gonna try the tru-boost controller and see if that helps it..

 

[numlock666]

run it without a MBC, Just run a vac line from the boost source to the wategate actuator.

 

[218dsm]

and if i run it like that and it still happens...??? then what?

 

[JDM_DSM]

Then your wastegate acutator is pooched. If you have a straight line from an intercooler pipe to the wastegate actuator and you boost past 10psi the wastegate isn't opening, or at least not opening enough.