ok so i have a mbc,catback,street tune,and 255 fuel pump on my evo 9 the car will not go over 15psi it just fuel cut whenever i raise the boost and everytime it hits around 6000 rpm it jus stop boosting i dont know what the problem is

 

u have a WB?? and who tuned it?

 

and sounds like your MBC is on backwards, or J-pipe return is bent... being that you are boosting only WG pressure..

 

no it was a local guy that tuned it around orlando the boost controller is on correctly but im going to have a look at the pipe thanks for the quick reply

 

the pipe is fine i still dont know what is it that is causing the car to stop boosting after 6000rpm in first and second gear its fine after that it just stop boostin

 

so in first and second gear you will boost above 15 but in 3rd and 4th no?

 

oh no im sry i mean first and second gear it will hold 15 psi past 6,000 rpm and the rest it wont

 

sounds like a bad tune...... go to a pro, also check for leaks just a suggestion.

 

yea thats what i was thinking maybe the tune

 

Did it ever work right after the tune?

 

i think this is why he is asking the question for its cuz its tuned and still not running right or there lack of a good tune

 

sounds like a leak or mbc set really low/ really weird tune?

 

yea it ran great after the tune and it was boostin more than 15 this started happening like 2 weeks after i installed the mbc they're telling me it could be a leak so far i checked the intercooler,intercooler pipes,vacum lines that is ran to the mbc that is it so far and they are fine

 

boost leak test it just by looking will not tell everything

 

getting somewhere now. So it started the low boost right after you installed the MBC then? Check how it's routed, what line goes where.