3 replies to this topic

[z31jaime]

OK so 2 days ago i finally put my MBC back in for testing. Im still trying to track down the vacume leak. (which i suspecte is why my car is pulling timing at WOT and Ideling at 1200RPM). I figured I could have a bad BCS and maybe I'd get luck and fix it with this. Anyways, I set it up, and its hitting 13psi but I'm having 2 issues... #1 its not feeling like a strong 13Psi. Like I remember before at 13PSI this thing would spin the hell out of the tires now it honestly feels the same as without the MBC. #2 I spike to 13psi, then slowly bleed boost to about 8psi.....where the car shifts and back up to 13 and bleeds again....

I'm throwing no CELs so Im having a hard time finding the leak. Most recently I replaced all the Intercooler lines with silicone ones. so that "should" be covered. Replace the hose from the IACV to the vacume tree. New silicone TB connector. I removed a cracked Snabb intake manifold spacer and replace it with an OEM gasket, so that should be new. All my silicone lines are new rubber lines. Intercooler has been checked and has no visible cracks.

So at this point I'm lost as to what it could be.

Anyone think maybe the CBV is torn? any other ideas?

[Tommy.]

Check intercooler pipes with soapy water out of a spray bottle.

[z31jaime]

update with video....

[SeedyRom]

Had the same issues with boost fade before upgrading to OBX turboback. CBV is possible too or also the wastegate might be too loose.