Help me understand why my MBC does not function properly
Apr 25, 2007, 03:34 PM
#34
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I found a small leak around the nipple FP put on the compressor housing for me... this will be a total PITA (maybe) to fix with the turbo on the car but i'm going to try. I also found a small leak around where the LICP bolts to the compressor housing.
I'll get these fixed and hope for the best! Sucks the damn undertray has to come back off ugh.
I'll get these fixed and hope for the best! Sucks the damn undertray has to come back off ugh.
Last edited by justchil; Apr 25, 2007 at 03:41 PM.
Apr 26, 2007, 06:49 PM
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&#@$&*@#*( this is annoying.
The WGA is now only holding 18-19psi when before it was 24. This is after fixing a couple leaks. I'll test again just to be sure there are no more but I'm already at 4 turns of preload on the WGA.
The MBC when hooked up with 10 clicks soft spring hits boost right one pull. Next pull it hits 34psi. With the MBC turned all the way down its hitting 23/24psi and pulls hard. Either way it tapers big time down to the WGA pressure.
Something is wrong here.. The fact that the WGA is now holding less has got me worried that I may have an exhaust leak or something. Does anyone know a good way for testing the o2 housing manifold etc.. for leaks? I have all the EGR stuff "disabled by running a hose from one nipple to another on the TB and the hardlines... I don't think this is the issue.
The WGA is now only holding 18-19psi when before it was 24. This is after fixing a couple leaks. I'll test again just to be sure there are no more but I'm already at 4 turns of preload on the WGA.
The MBC when hooked up with 10 clicks soft spring hits boost right one pull. Next pull it hits 34psi. With the MBC turned all the way down its hitting 23/24psi and pulls hard. Either way it tapers big time down to the WGA pressure.
Something is wrong here.. The fact that the WGA is now holding less has got me worried that I may have an exhaust leak or something. Does anyone know a good way for testing the o2 housing manifold etc.. for leaks? I have all the EGR stuff "disabled by running a hose from one nipple to another on the TB and the hardlines... I don't think this is the issue.
Last edited by justchil; Apr 26, 2007 at 06:52 PM.
Apr 27, 2007, 05:32 AM
#37
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I'm going to tear the car apart this weekend and look for problems. At this point I'm ready to give up alky so I don't have need for a MBC... or rebuild my hallman and use it cause in the 2.5 years I owned it I never had any problems like these.
I still need to give Forge a call to see if they want to do anything or look at both the MBC's and the WGA so I can get them sold to recoup some $$$.
I still need to give Forge a call to see if they want to do anything or look at both the MBC's and the WGA so I can get them sold to recoup some $$$.
May 1, 2007, 05:45 AM
#38
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I'm finally boost leak free. I still need to pull the under tray off and triple-check the LICP for leaks. I still need to look for any exhaust leaks which I'll be doing tonight.
When I leak test now the system holds 25psi. I've noticed that air is coming out of the breather hose on the valve cover. The car doesn't smoke or burn oil so I'm thinking it's not in "TDC" so this may be why air comes out here?
I still have boost issues tho... falls like crazy around 5-6k. Spikes crazy high in 4th and 5th gear even with the MBC turned all the way down (I'm talking 34psi here!). Once exhaust leak is out of the picture I'm out of stuff to try. The only thing left to do will be to preload the WGA another turn and buy another brand mbc to try.
When I leak test now the system holds 25psi. I've noticed that air is coming out of the breather hose on the valve cover. The car doesn't smoke or burn oil so I'm thinking it's not in "TDC" so this may be why air comes out here?
I still have boost issues tho... falls like crazy around 5-6k. Spikes crazy high in 4th and 5th gear even with the MBC turned all the way down (I'm talking 34psi here!). Once exhaust leak is out of the picture I'm out of stuff to try. The only thing left to do will be to preload the WGA another turn and buy another brand mbc to try.
May 1, 2007, 09:16 AM
#40
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I'm using the FP upgraded unit. I have a stock one but I really don't wanna drain the coolant again 
It could be that I set my preload with leaks in the system and now that the leaks are gone my boost is lower? Just doesn't make sense but adding more preload will fix this problem I'm sure... I just want to make sure I'm not missing anything else before doing so.
It could be that I set my preload with leaks in the system and now that the leaks are gone my boost is lower? Just doesn't make sense but adding more preload will fix this problem I'm sure... I just want to make sure I'm not missing anything else before doing so.
May 1, 2007, 09:49 AM
#42
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Soft spring... which works fine when the wga was preloaded to 24psi. Now it's only holding 18-20 for some reason. The stiff spring sticks after about 2 mins and I'm stuck at WGA pressure.
May 1, 2007, 11:01 AM
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I got rid of my forge wga which was giving me problems too, but the problems you're describing happened when I was running the stiffer spring. I guess you're going to have to try and preload the actuator again. I know that's going to be a pain but it should help.
May 1, 2007, 11:05 AM
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Why would you drain your coolant to take WGA out? but like you said you got FP one so theres no need to do that, maybe try to pre-load it again with less turns? I would definetly use stiffer spring for your mbc, make sure its clean inside and do not use any oils. Try different MBC.
May 1, 2007, 11:10 AM
#45
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Well I busted my stock radiator taking a WGA out so rather than make that 300-400 $ mistake any more I play it safe. I can adjust it no problem being in the car... I just put cardboard in the way of the radiator.
I preloaded it a full 4 turns and it would hold almost 25psi to 7000rpm. Shortly after that a vac line popped off and I found a couple other little leaks... after fixing all this the WGA is now only holding 18-20psi which made me wonder what else could be wrong.
If I preload the WGA more it should bring the boost back up where I need it but with 4 full turns it was VERY difficult getting the pin in the hole.
I've tried everything with the stiff spring tho.. I would clean it out reseat it and it would work great for a few minutes then start sticking. I have bought 2 Forge MBC's and both do this.
I'm about to the point of having someone else look at it... Maybe I'm overlooking something or making it more difficult than it really is.
I preloaded it a full 4 turns and it would hold almost 25psi to 7000rpm. Shortly after that a vac line popped off and I found a couple other little leaks... after fixing all this the WGA is now only holding 18-20psi which made me wonder what else could be wrong.
If I preload the WGA more it should bring the boost back up where I need it but with 4 full turns it was VERY difficult getting the pin in the hole.
I've tried everything with the stiff spring tho.. I would clean it out reseat it and it would work great for a few minutes then start sticking. I have bought 2 Forge MBC's and both do this.
I'm about to the point of having someone else look at it... Maybe I'm overlooking something or making it more difficult than it really is.