ok i am very new to this so here is my problem i have a 2003 evo that is only boosting 9 Psi . I was told that there are special stock vaccum lines that cant be replaced this will mess the boost up. Is this true? also i think the person before me had some type of flashing going on can this effect it also . i bypassed the waste gate and still only 9 Psi. Please help

oh by the way i checked all the vac lines already and still have no clie what this could be

 

the stock lines have been replaced due to the fact the old owner had a boost control

 

u did a boost leak test?

 

Go buy a MBC and turn it up see what happens...what you have heard is true you need you stock lines if you are running stock parts.

 

ok so if what your saying is true the flashing of the compter could that have anything to do with it

 

If your stock boost controller(found below your intake) still has all the nipples on it then just connect your vaccum line to that.

 

ok so i put a mbc on it and i am now getting 10 or 11 Psi but it runs better i think previous owner messed up the ecu he flashed it and did his own programing instead of someone who knew what they were doing

 

^
If you put a MBC on it and it wont go over 12-14, then theres something wrong with the lines and/or MBC. The ECU being flashed in anyway wouldn't do anything when using a MBC.

Go buy the lines from Mitsu (you need to get tehm here not at auto store) and get the car workin correctly before puttin on a MBC or any other mods.

 

well he messed up the air fuel so as i understand the car won't boost if there is no gas for it to boost so i am taking it to the dealer to flash it to factory specs. what is the stock boost on these cars i was told 16 then i was told 19

 

i am pretty sure stock boost on evos are 19 psi.

 

was or is yours on your 03 evo