i was out driving today and i noticed my knock light coming on a lot. first thing i check when that happens is how much boost did i come upon during that little pull. well i saw my gauge went all the way up to 2bar. so i started trying to see what was causing this. i gradually let the turbo spool up and i saw that again and again it would just go right past 21 psi. I thought maybe it was my MBC so i stopped to turn that all the way down. still the same problem, the boost just doesnt stop. And im not just mashing the gas, i was letting the boost slowly build. It did this the whole way home... obv i stayed out of boost, but i checked a few times along the way

ive noticed this happen before a few times but usually its just random. if i just stomp on the gas sometimes it will boost all the way past my set limit of my MBC and it will just stay there. However if i catch it overboosting i can let off the gas and get back on and the problem goes away. it will stay at 21psi.

before today i thought these random situations were just the gauge and maybe it was reading the boost wrong. when i first installed it as soon as i would hit 1psi of boost the needle would just shoot all the way up to 2bar. so i rewired it and it has been working perfectly.

I think the gauge is fine, i checked all the lines and ive checked boost off the 2-step and its the same as usual. idk what it could be. Is it possible that my wastegate is stuck closed?? I have not checked the actuator, maybe it is stuck... ive read a few threads of ppl having them stuck open but none closed

 

i dont get it. I just checked and all the vac lines from my MBC are connected to the wastegate. everything looks good. its still doing the same thing. should i be able to open the wastegate by hand, like to check and see if its stuck?

 

How can "ALL" lines from the MBC be connected to the wastegate? You mean both lines from the MBC, as there are only two. Furthermore, the wastegate actuator only has one port(nipple), so you can only connect one hose to it. I can see why you are experiencing problems. What me worry?

 

[quote=Oki Panoki;697270.... i gradually let the turbo spool up and i saw that again and again it would just go right past 21 psi. I thought maybe it was my MBC so i stopped to turn that all the way down.....[/quote]

First off, we need to be speaking the same language. So take a step back. When you say that you, " turn(ed) that all the way down". Do you mean that you tightened the knob all the way in clockwise? Or that you backed the knob all the way out, counterclockwise to it's lowest boost setting?

 

yes two, all, same thing just the first word that came to mind. from turbo to mbc, then from mbc to actuator nipple. if you were wondering which boost source i was using

edit: woops, yeah i see what you meant by all... yeah stupid of me, but i already covered that so.
i turned it counterclockwise. ive messed with my MBC many times before with the changes in weather and what not so i know i did that correctly

 

problem solved. Not really sure what happened. i messed with the actuator a little bit and i got it to move. im pretty sure that it was stuck before. after i got it moving i went to drive it and the boost shot up past what it should have (12 r so psi). however it didnt go all the way to 2bar like it was before, it went to maybe like 1.7 then shot back down to the 12psi it is supposed to be at. Still a little confused what happened because the actuator seemed to move but when i drove the boost went up and then seemed to pop open. after that it held the 12psi perfectly fine so i turned it back to where i had it before the issues started.

not sure how i never hit boost cut or fuel cut either. i think my boost limit table is set pretty high thou so that might be why

 

I have the same problem with my evo 8 it boosts way to much and i got a mbc and its set all the way down...i was thinkin it could be stuck from sitting for a long time....its tuned to boost at 23 psi and on my boost gauge it gord past 2 bars and i dont know wat to do...how did u say u fixed urs exactly?

 

some mbc's will cause over boosting