6G Celicas Forums

Hi all, was wondering if i can get some feedback on something i was missing. here's the story:

recently a friend and I fixed a leak due to stripped thread in the head causing a leak between the exhaust manifold and block.

after rethreading and putting everything back togehter leak is gone BUT now im seeing much lower boost numbers after taking it for a drive.

I own an AEM tru boost controler/gauge and the boost is currently set to stock wastegate pressure (8psi) and consistently held this pressure PRIOR to fixing the exhaust leak.

as of today, my first drive out, my car would not pull past 5psi and touched 6psi BRIEFLY. I double checked my IC piping and adjusted and retightened.

when i went back out the car would only boost up to 4-5 psi adn sometimes as low as 2-3 max.



Im pretty sure its a leak somewhere but it can only be one place as the only IC piping that was removed was the piping coming from the turbo (charge side) i have checked and double checked it.

is there something im missing? any helpful hints would be appreciated! thanks!

Have you tried to readjust the true boost?

nah the lines coming from the tru boost are not hooked onto the wastegate and turbo yet. i have still been running it on the wastegate until i got the exhaust leak taken care of.



This post has been edited by easternpiro1: Apr 28, 2012 - 4:19 PM

Reconnect sir.

its never been connected to the tru boost. its always been wastegate i may have overlooked piping closer to the intercooler, will check that. it couldnt be anything else because nothing else was taken off except the turbo/manifold

i want to hook the trueboost up, but if its not acting right on just wastegate pressure, im afraid upping the boost will only make matters worse?

build a boost leak tester, bro, theres gotta be a leak somewhere.

Yeah, its pretty sporadic. im going to have to go to lowes this week....


http://youtu.be/atretf9u-Mc

bad boost controller? like a bad spring

nah, couldnt be, its brand new, and this only started happening after i removed the charge piping to take care of a stripped bolt on exhaust manifold

open waist gate or bov?

yea i'd vote that wastegate is blowing open or is stuck open

hmmm. im about to ask a silly question... how do i get it unstuck?


I tightened down the piping again to be sure, took it for a drive, and NOW it wont build boost AT ALL. i only took the car to the end of the street, but i could tell after only getting on it up to 3000rpms in 2nd gear that it wasnt acting right... hell i could tell by the vac on the gauge (reading at 16-15)


def making that boost leak tester today or this weekend when i can get the chance. this is craziness lol.

hmmm. im about to ask a silly question... how do i get it unstuck?


I tightened down the piping again to be sure, took it for a drive, and NOW it wont build boost AT ALL. i only took the car to the end of the street, but i could tell after only getting on it up to 3000rpms in 2nd gear that it wasnt acting right... hell i could tell by the vac on the gauge (reading at 16-15)


def making that boost leak tester today or this weekend when i can get the chance. this is craziness lol.

You take the downpipe off and you'll be able to see it. sometimes you'll need to replace the wastegate actuator (if that is causing it)
or it might be getting stuck on the downpipe flange (i believe i recall this happening on 3sgtes with an aftermarket downpipe, but that recollection is from years ago)

it really depends why its stuck open as to how you unstick it.

hmmm i will def check that out too this weekend! I just bought materials for the boost leak tester, I FAILED by buying a pipe drain cap that was too big lolz going back to lowes tomorro

HEY, didnt get to pressure test it yet, BUT readjusted some more piping, and a friend noticed that my wastegate line was a little crooked, after adjusting it, it boosted better initally, but went right back to NO boost at all. going to try to test today or tomorrow, it MAY be a bad wastegate... its moving but the diaphram on inside may be messed up

HEY, didnt get to pressure test it yet, BUT readjusted some more piping, and a friend noticed that my wastegate line was a little crooked, after adjusting it, it boosted better initally, but went right back to NO boost at all. going to try to test today or tomorrow, it MAY be a bad wastegate... its moving but the diaphram on inside may be messed up

any plug wires get damaged during maintenance? (slightly) pulled out from the connector?

I dont think so. I dont have any wires, its coil on plug. its really weird. the BOV wont go off, indicating a leak BEFORE the Throttle body i suppose? im really hoping its not turbo related. but more and more its seeming like it.

OOOKAY. I took apart ALL of my IC Piping, cut larger diameter holes for the charge piping and cold piping to go through, as it was rubbing, and used my nifty boost leak tester to find any leaks in the system.


I heard no air escaping from the lines which led my friend to believe that my blow off valve is probably leaking (hence the stuttering and NO boost being built under load) I have a TIAL Q. I will be trying a heavier spring, and HOPEFULLY that will fix the problem... I'll be saying my prayers extra hard lol.

if its not the BOV, my attention will FULLY be turned to the wastegate possibly being stuck open (which we believe may not be likely due to the fact that after preloading it, it built up to 8 psi as hoped, then dropped later.


UGH.