Perform a pressure test on the car because its not holding boost. The boost pressure comes on quick like normally does but it would fall down to 12 psi. I have secure down the snorkle, check and grease the bov, test the actuator they all seems to be working fine. During the boost leak test every thing is fine except for my Turbo xs mbc. It starts to leak at aroun 15 psi. I tighten the fine adustment down and it help alittle but still leaking from the mbc. Check the hoses and their fine. Is the mbc suppose to leak like that?

The car was working fine at 21 psi for 2 years until recently when I notice it after I got my X flash. Would the flash cause my boost problem? I only dive the car once in a while so the problem might be there before the flash.

 

If you say that same MBC worked fine for 2 years, then I don't really know, but if you do a quick search on that MBC, you will find a slew of people who ditched it for a better one. Again, if everything was fine until the flash, then I would try to find out what else changed when getting the flash.

 

I have a Hallman MBC and couldn't be happier. Goto Hallman's website and read up in the FAQ questions regarding their boost controller.

I noticed my Hallman held a little better than my Buschur MBC, although the Buschur is also a good design.

 

That is how a MBC works. It bleeds off boost at a certain PSI. Disconnect the boost source from the MBC and plug the hose while you do the test.

 

question.....

im doing my pressure test again right now and noticed that at 15psi it starts leaking from the hallman MBC.
I have the hose connected to the wastegate plugged up and i left the other hose from the MBC to the bov/intake manifold ON.
The leak is coming from the MBC where the wastgate is supposed to be conncected.

Am i doing this right?
Is my MBC leaking?

 

You're unplugging the wrong side.

 

I thought the wastegate side of the MBC suppose to bleed off PSI at the set point, not before it - which I have tried adjusting it to the max setting and it still bleeds off a little. Correct me if I'm wrong.

 

what are you boosting up to?

and was this a custom flash or mail in?

that and most likely it's your mbc not working properly that or something has gone wrong with your bov, lower ic piping, or your wastegate.

you know those springs do loose their tension after a while and if you had it for 2 years.... well...

 

Your boost controller can't bleed anything if it doesn't get a signal. You have to disconnect the boost source. I've been doing these leak tests for 10 years.

Trust me