Problem with MBC/BOV

[4GSixty3]

What he said.

 

[CBT8503]

Yeah im still a newbie at this whole thing, so im still having a hard time picturing what you are telling me to do. So I take off the line that i'm T'ed into?

 

[oldman]

Yeah im still a newbie at this whole thing, so im still having a hard time picturing what you are telling me to do. So I take off the line that i'm T'ed into?

Basically the goal is to connect the shortest hose possible between the nipple on the mbc and the nipple on the compressor housing nipple (originally connected to the right of the T), then eliminate all other hoses and the T. If you look to the left of the T, you will see the bcs (boost controller solenoid). You will also need to remove the hose between the bcs and the intake pipe, then cap off the nipple on the intake pipe. It's a lot harder to explain than it seems.

The problem you have is that the bcs should have been disabled when a mbc is installed, who ever installed the Joe P got it all wrong. You eventually have two boost controllers hooked up side by side.

 

[CBT8503]

Yeah the guy that installed it apparently didnt' know what he was doing, I already fixed a few of his mistakes.. but you live and learn I guess? So i'll take the line I T'ed into off, and go straight from the MBC nipple opposite the knob stright into the bottom of hte turbo (where it's connected now but suptract the T)? And cap off the line that leads from the BCS to the intake pipe?

 

[oldman]

Yeah the guy that installed it apparently didnt' know what he was doing, I already fixed a few of his mistakes.. but you live and learn I guess? So i'll take the line I T'ed into off, and go straight from the MBC nipple opposite the knob stright into the bottom of hte turbo (where it's connected now but suptract the T)? And cap off the line that leads from the BCS to the intake pipe?

I think you got it.

 

[CBT8503]

Thanks i'll try it out and let you know how it goes.

 

[GS_EX_99]

Weird how im having the same problem, I have a Greddy type S but it is working fine. And i have a Bleed type MBC by Turbo XS. I have already corrected the way it was hooked up and now i am hitting 16psi and dropping to 14 and holding. I am trying to get it to hold 16psi, but it just wont. any other tips?

 

[oldman]

Weird how im having the same problem, I have a Greddy type S but it is working fine. And i have a Bleed type MBC by Turbo XS. I have already corrected the way it was hooked up and now i am hitting 16psi and dropping to 14 and holding. I am trying to get it to hold 16psi, but it just wont. any other tips?

First perform a leak test and make the system is leak free. If problem persists after that, you have boost spike not boost dropping off. I have helped some Turbo XS bleeder type mbc users and this seems to be a common problem. Instead of thinking you set the boost at 16psi then drops to 14psi, you actually set it at 14 psi but it spiked to 16psi. To run at 16psi, you would let set it at 16psi and let it spike to 18psi for a split second. Again, this is only true after you're sure the system is leak free.

 

[CBT8503]

I did what you said and still it seems to want to go to 20+ PSI.... im in the dark as to what could be wrong here, and have noone around here that knows abouts DSMs enough to take a look at it. I think my next bet is to take the MBC apart and see if thats the problem, but then again i've never done that before either. Any help is appreciated.

 

[oldman]

I did what you said and still it seems to want to go to 20+ PSI.... im in the dark as to what could be wrong here, and have noone around here that knows abouts DSMs enough to take a look at it. I think my next bet is to take the MBC apart and see if thats the problem, but then again i've never done that before either. Any help is appreciated.

Relax, you're almost there.

go straight from the MBC nipple opposite the knob stright into the bottom of hte turbo (where it's connected now but suptract the T)?

Since we can't see this nipple on the picture, make sure that it's coming from the compressor housing and is a proper pressure source. More pictures would be helpful.

 

[GS_EX_99]

I did a Leak Test on Monday, and Fixed 2 leaks. Everything is leak free. Heres my Problem, I set up the MBC from the wastegate to the comressor housing(MBC nipple opposite the Screw went to the Compressor housing nippple on the bottom side of my t-25)
When the screw was set all the way in I was getting 12psi spike and 11psi holding(3rd gear pull) It took 4 Full turns to get 1psi on the. So by the time i got it up to 14psi the Screw was almost all the way out the top of the MBC. So then I came on here and did a search and saw that a ton of people were T'ing off the Bov Vacuum line to the Intake Manifold, so i tried that, got 13psi before i realized how stupid i was( bleeder holes turned into boost leaks after 13psi). So I am out of ideas and I took off the MBC for now.

Also when i hooked the MBC up to the Compressor housing I left the Boost Solenoid pluged in, Not sure if i should have unpluged it or capped the 2 nipples off.

 

[oldman]

I did a Leak Test on Monday, and Fixed 2 leaks. Everything is leak free.

Make sure the system is able to hold 20psi for at least 30 seconds.

Heres my Problem, I set up the MBC from the wastegate to the comressor housing(MBC nipple opposite the Screw went to the Compressor housing nippple on the bottom side of my t-25)

Unless there is a new model out, I'm pretty sure the Turboxs unit is oposite of a ball/spring type mbc. The pressure source should go to the bottom nipple and the nipple opposite the adjustment screw should go to the actuator.

t-25

Forgot to check your profile before my last post, T25 is known to spike.

Also when i hooked the MBC up to the Compressor housing I left the Boost Solenoid pluged in, Not sure if i should have unpluged it or capped the 2 nipples off

Leave it plugged so you won't throw a CEL. I would cap them off in case if you want to return to stock later and don't forget to cap off the nipple on the intake near the mas.

 

[GS_EX_99]

It was holding 25psi, but not sure how long.

I'll post tomorrow and give some results.