EVOIII 16G, Still cant control boost, Tried EVERYTHING...Please Help!

[TurboDreamzGST]

So I have a 98 GST Spyder, newly installed ebay version of the big 16g turbo. Im having problems controlling my boost all together. It doesnt hit a certain point and than "creep" up, it just constantly jumps straight up to over 20 PSI easily. I have a ported 2g exhaust manifold, Megan Racing O2 housing, 3" cat-back exhaust (the problem occurred before AND after the cat-back exhaust), and manual boost controller. Ive tried turning the boost down completely using the MBC but nothing happened. So than I adjusted the waste gate actuator arm and loosened it so that it just slides right onto the wastegate flapper because it was much too tight when I first installed it and nothing happened. I than pulled off the turbo and ported out the waste gate opening underneath the flapper and re-installed it and still nothing happened. So I hooked up an air compressor directly to the line to the waste gate and it opens fine. What else could it be? This is REALLY frustrating and im just completely lost. Please help me out guys!


Also forgot to mention that Ive tried several MBC's to see if mine was bad, I even pulled one off of my friends 95 GST so I knew it was in good working condition. I also tried using his boost gauge and than a new one that I purchased to make sure that the one I had wasnt just giving me wrong readings. Neither of this things are the issue.

 

[srpjosh]

Is your boost gauge electric or manual? Also, try replacing your MAP sensor. Mine did the same thing and a MSD MAP sensor fixed it.

 

[the_mork]

His car doesn't have a map sensor, it has an MDP sensor but it has nothing to do with controlling boost or really anything else. It detects if the EGR system is working or not so putting a new map sensor on the car wont help anything.

It sounds like you aren't getting vacuum/boost signal to the actuator or the wastegate flapper itself is stuck. Start by taking off the actuator entirely then drive the car and see if it spikes, it shouldn't build more than a couple psi without the actuator on. If that is fine then do a boost leak test and see if you are getting enough signal through the vacuum line or if it has a leak or tear in it somewhere.

 

[viperlp01]

That or try bypassing the mbc and run it straight to the wastegate... It should open at after 7psi.. Sorry to hear all these probs your having

 

[14spectre88]

It sounds like you aren't getting vacuum/boost signal to the actuator or the wastegate flapper itself is stuck. Start by taking off the actuator entirely then drive the car and see if it spikes, it shouldn't build more than a couple psi without the actuator on. If that is fine then do a boost leak test and see if you are getting enough signal through the vacuum line or if it has a leak or tear in it somewhere.

I totally agree.

That or try bypassing the mbc and run it straight to the wastegate... It should open at after 7psi.. Sorry to hear all these probs your having

He already said he's tried multiple boost controllers and he tested his actuator...

 

[TurboDreamzGST]

I dont think my actuator is stuck because I tested that already and when i hooked up the air compressor to it, it opened up fine, and I'm sure theres no leaks in the vacuum lines because i also changed to new vacuum lines and when I tested the wastegate with the compressor I had the air running through the same lines that i use. I just cant figure it out and its KILLING me. BTW I have my MBC set up as follows: The line coming off of the wastegate solenoid going into the boost controller and than a second line coming off the other side of the manual boost controller going straight to my waste gate....i do not have a line that goes to my turbo itself like my t-25 did because there is no nipple on the new 16G to hook up a line to it...just wanted to throw that out there in case i may have missed something or if it helps at all....please help me guys, im pulling my hair out over here.

 

[Jafro]

Your boost controller's boost source is a solenoid.

Your actuator is not seeing any vacuum so the wastegate isn't opening. Take your boost control solenoid out of the mix entirely. Leave the electrical connector on it, and leave it in the engine bay, but lose the vacuum lines. It will throw codes if you remove it, but it won't if you take off the vacuum lines. It's really not doing you any good now that you're running the 16G, and disconnecting it won't have any effect on how your car runs. Tee your MBC off the BOV hose and your problem will be solved as long as it's a ball & spring MBC.

 

[TurboDreamzGST]

Ok i'll def. try your suggestion but the MBC i have is a little unclear as to which way it should be installed...could you just take a look at the pic i posted and tell me which vacuum line should go to which port on the MBC please? i just wanna make sure i'm doing everying 100% right...thanks again...right now i am only using the MBC itself because i am unsure on exactly how to hook up the "T" because i dont have a nipple on my turbo itself...can someone please explain to me in detail how I should go about properly installing this style boost controller, i have searched all over and realized that this is a bleeder style MBC and not a ball and spring type which i didnt even know...now i'm thinking that my boost issue might actually be caused by connecting my MBC incorrectly because i was installing it as if it were a ball and spring type and using only the MBC itself without the "T" that was included.

 

[debbie]

I would say the arrow is not pointing away from anything its telling you that's the direction of the air flow from the source and the other barb would go to your actuator, Basically in and out? So you should, looking at the picture above, take an air line from say your J pipe and connect it to the bottom barb, the one with the arrow beside it, and then run a line from the top one to the actuator.

I just noticed that you said you have a bleeder, I;m not sure about them but i think i read they arnt good for our cars???

 

[rush2252]

I think the issue might be the MBC. Those got Negative reviews with everybody that bought them.

 

[debbie]

I think the issue might be the MBC. Those got Negative reviews with everybody that bought them.

He said he tried other MBC, it looks to be the way he has them set up?

 

[AndrewD5418]

Look on how to hook up a turbosmart MBC. http://www.turbosmartonline.com/index.php?s=file_download&id=200

 

[eclipse-gs-t]

well what about the wastegate, mine did the same thing and it was because of the wastegate.

 

[the_mork]

Considering you don't have a nipple on the turbo where are you getting your boost source from? Do you have one on your intercooler piping now? If you have to you can T into the bov vacuum line but this is generally not suggested because there is a bit of signal lag and it can cause your bov to be harder to open. This sounds like your problem, that everything is hooked up enough to work (though not ideally) but you have no reference to start with.

 

[purewake07]

Have you checked to see if the MBC is just too tight or backwards? Unscrew the MBC all the way until it almost falls out of the threads, then tighten it a half turn just to keep it together and floor it again. if you feel it jumping to wicked RPMs, stop and turn the mbc around and try again.

 

[Jafro]

There won't be any nipples on a '98's intercooler piping unless the J-pipe he's using has one added to it.

I would get a ball & spring MBC, tee it off the bov, and call it a day. When I used to have the needle-valve style MBC, I had to connect it in 4 different places with 2 tees and one vacuum line even had a restrictor in it. One line on the intake, one on the BOV line, one on the wastegate, and one on the MBC. I don't know which one went where, but it was a pain. Junk, IMO. The ball & spring units are so much simpler to deal with.

 

[Dert]

There won't be any nipples on a '98's intercooler piping unless the J-pipe he's using has one added to it.

I would get a ball & spring MBC, tee it off the bov, and call it a day. When I used to have the needle-valve style MBC, I had to connect it in 4 different places with 2 tees and one vacuum line even had a restrictor in it. One line on the intake, one on the BOV line, one on the wastegate, and one on the MBC. I don't know which one went where, but it was a pain. Junk, IMO. The ball & spring units are so much simpler to deal with.

+1, I would check out NXS's MBC on ebay, they have excellent reviews, alot of people use them, they are only like $20 and if you email the guy (his name is Phil) and tell him you are a dsm tuner you will get a $5 discount. Again these little ball and spring mbc's work really good and I don't think anybody has had a problem or anything bad to say about them. The T style like the one shown in the picture are known to not hold boost, they either spike waaay to high or you get no boost at all, never a happy medium, so try the NXS one, might fix your problem and be the best $15 you spent on your car yet

 

[debbie]

+1, I would check out NXS's MBC on ebay, they have excellent reviews, alot of people use them, they are only like $20 and if you email the guy (his name is Phil) and tell him you are a dsm tuner you will get a $5 discount. Again these little ball and spring mbc's work really good and I don't think anybody has had a problem or anything bad to say about them. The T style like the one shown in the picture are known to not hold boost, they either spike waaay to high or you get no boost at all, never a happy medium, so try the NXS one, might fix your problem and be the best $15 you spent on your car yet

+1 i bought the bleed type and didn’t even bother fitting it i just sold it and got a ball and spring type.
The problem is he said he tried other MBC, so unless he can come back and confirm if they were all the bleed type or were some ball and spring?
It sounds though he may have two problems 1 he’s hooking them up wrong and two he has an incomplete BOV set up and or the wrong type.

 

[TurboDreamzGST]

Ok so i set up my MBC like the Turbo Smart set up and it worked! only 1 problem....the boost spikes to 15 psi but than just drops off to like 8-9 psi and holds there...i'm thinking it probably just because of the sh!tty MBC itself, i'm thinkin of ordering a ball and spring type today and just setting it up that way...do u guys think that could be why thats happening? Or do you think if i now tighten up my wastegate actuator arm that should help to hold my boost around 15? because i loosened the arm because i thought that might be the reason that i was boosting so much. and i just wanted to tell everyone who contributed, thank you sooooo much! i am eternally grateful for all the help you guys have given me....i'm just happy that my boost is FINALLY at a safe level thank you all again.

 

[Dert]

Ok so i set up my MBC like the Turbo Smart set up and it worked! only 1 problem....the boost spikes to 15 psi but than just drops off to like 8-9 psi and holds there...i'm thinking it probably just because of the sh!tty MBC itself, i'm thinkin of ordering a ball and spring type today and just setting it up that way...do u guys think that could be why thats happening? Or do you think if i now tighten up my wastegate actuator arm that should help to hold my boost around 15? because i loosened the arm because i thought that might be the reason that i was boosting so much. and i just wanted to tell everyone who contributed, thank you sooooo much! i am eternally grateful for all the help you guys have given me....i'm just happy that my boost is FINALLY at a safe level thank you all again.

If you have the $$ get a hallman, if not go with nxs off ebay, as I stated before it's inexpensive and extremely reliable, you can try to tighten your actuator arm up a little but to be honest that t-style mbc is known for not holding steady boost, like I said the nxs mbc will be the best $15 you spent on your car

 

[TurboDreamzGST]

ok sounds good man! thanks a lot!

 

[rush2252]

If its dropping off you might have a boost leak.

 

[mrTalonAWD95]

i used to have that mbc and it started messing up after a while. that second little piece that comes with the boost controller has a ball and spring in it, youll have to modify it to work properly. i threw my boost controller away and used the second piece as an mbc. i just pulled the spring and made it stiffer and it stays on 15psi without problems.