6G Celicas Forums

hey whats up guys, once again i have ran into another issue. this past weekend i was doing some tuning on my car and i wanted to UP the boost a little bit more, but to my surprise i cant go past 11psi......


i did another boost leak test and my intercooler pipes( inlet to outlet) hold 15psi without trouble and the pressure stays pretty steady....so no mo major leaks there...



i got a cheap MBC


when the MBC is closed i boost 7spi which is the wastegate spring load

MBC half way open = 11psi

fully open = 11psi

if i remove the boost controller and leave the hose that connects to it by itself, still get 11psi.............


so i im assuming i must have a leak somewhere past the throttle body...im not sure how to test the intake manifold and all other vac lines to see if i got a leak there under pressure, because in idling i sprayed starting fluid around injectors, manifold, ects. and idle didnt change.


or is it possible that my EGR could be leaking???


any help is appreciated

C'mon guys, im sure somebody knows how to truouble shoot this issue

How do you know you're boosting 11 PSI?

Boost gauge or data log?

you are flirting with disaster at that high a boost. i dont think i went much over 10. its been so long, i just cant remember

I got no signs of detonation, or knock wat so ever and im a,little on the rich side on my afr (11.5} im using my boost gause to check my psi. Today I disconnected the line going to thee WG and still 11psi... What the heckk is going on .....boost should have gone way up!

Boost gauges can go bad. I bet that's your problem...

The booost gauge is still pretty new. If it was bad at least I would feel the extra power. Ive been searching other forums and I got the idea that my exhaust might be too small. Alll my exhaust is 2.25" starting from the downpipe

what turbo? wastegate door being blown open?

it could be the exhaust. it might be too restrictive causing it to prevent the turbo from spooling more.

Sounds like wastegate problem. It might be stuck open or the arm moving easily. GL.

i think i found my problem, i was checking the car while it was on with a hose to my ear trying to listen around injectors, TB, etc. and i heard hissing sound coming from the back of my throttle body right by the IACV....that might explain why my idle would not go lower than 1100rpm without retarding timing..... im gona fix that leak today and hopefully i should be boosting a little better. thanks for the replies

So, I fixed the leak on the throttle and still have the same problem. I even tied the wastegate arm with a wire to keep it from opening. I don't know what else to try. .

Maybe I'll upglsize the downpipe this week to see if that helps... any other thoughts?

did you ever find the issue? im begining to think im having a similar problem....

it turns out it was my wastegate arm. it was some what at an angle and even though the flap seemed closed it remained a little open.

i had tried holding the wastegate closed with a wire before and i had the same problem, only boosting 11 psi, but the wastegate arm was still connected......



i completely removed my wastegate and tied the flap closed again with a wire; when for a spin and shot all the way to 15psi. thats how i knew the arm was at an angle keeping the wastegate a little open.

soon after that i noticed my turbine wheel was chipped...i had no filter so most likely something flew in and broke it



so i got myself a new turbo, a i correctly positioned my wastegate...and this time i went with a 50 trim instead of the 57 and boosting around 14 psi and i get spool at 2500RPM and get full boost at about 3k RPM =]


happy camper! lol

thats good to hear!! i checked my wastegate and it too seemed closed. i havent took my entire wheel out (as my turbo/manifold is one piece) but i have to figure out something... im not getting any boost at all...