Boost problem

[eighty-eight]

Hey guys just having a small problem with my 7mgte. Firstly I'm hoping its something I can fix myself so I can save a few $$'s and just for the learning side of things.

The problem is I cant get over 15psi of boost pressure when I should be able to make 21-22psi. It used to make 19psi without a problem until one day it just dropped to 14-15psi for no reason.
I have replaced hose clamps and checked vacume lines for leaks and cant find anything. I was thinking it might be my waste-gate spring but the screamer isn't making much noise at 15psi.. Its not my boost controller either (GFB atomic) because I took it off and tried without it with no avail.

Any ideas guys?? im stumped

[EldarO]

maybe your wastegate wasnt working properly before, and it's loosened itself up?

or you have a boost leak?

is the car running properly? or are there other problems apart from the lwoer boost?

how solidly was it holding boost at 19psi? and why did it drop? aftera spirited run? weather? cold? hot?

Elmo.

[Adrian]

Im not sure if this will help or not, but is everything spooling ok?

[eighty-eight]

maybe your wastegate wasnt working properly before, and it's loosened itself up?

or you have a boost leak?

is the car running properly? or are there other problems apart from the lwoer boost?

how solidly was it holding boost at 19psi? and why did it drop? aftera spirited run? weather? cold? hot?

Elmo.

What do u mean by loosened itself up??
The car is running fine, no idle problems, not running rich or anything, only thing is it wont go over 15psi.

It was fine at 19psi and held it nicely. I think it was just after cruising on the highway at night driving normally so it wouldn't have been hot but i didn't notice until I gave it some maybe the next day or something... I cant remember sorry..

Im not sure if this will help or not, but is everything spooling ok?

Yeah it comes onto boost normally..

[The Real Roadrunner]

if the screamer isnt making noise its a fair call to say the turbo isnt making the required boost to open the gate.
check the shaft for play and make sure the wheels dont touch the housings
is the car quieter than before or making a rattle from the exhaust. if so check the cat hasnt failed or a muffler fallen apart internally.
are there any sections of the cooler piping that may have rubbed on something and made a hole in the pipes/hoses(seen that too many times).
is your intake pipe old and collapsing under boost.
anything out of the ordinary that you have noticed since apart from lack of boost/screamer pipe noise.
more info will help greatly in solving your prob!!!

[BeRad]

how do you have the controller hooked up to the gate.

do you have the bolt in the top of the gate controlling boost or the gfb controller?

I used to run the bottom vac port into a cooler pipe or the plenum, and the top where the bolt is, buy a barbed fitting and run a bit of hose into the controller then out of that into the plenum. Or maybe thats the only way to do it and im wasting everyones time .

[eighty-eight]

if the screamer isnt making noise its a fair call to say the turbo isnt making the required boost to open the gate.
check the shaft for play and make sure the wheels dont touch the housings
is the car quieter than before or making a rattle from the exhaust. if so check the cat hasnt failed or a muffler fallen apart internally.
are there any sections of the cooler piping that may have rubbed on something and made a hole in the pipes/hoses(seen that too many times).
is your intake pipe old and collapsing under boost.
anything out of the ordinary that you have noticed since apart from lack of boost/screamer pipe noise.
more info will help greatly in solving your prob!!!

Theres about 1mm of play in the shaft and its not touching the housing...It is a fair bit quieter than it used to be but its not rattling from anywhere other than the clutch..

I took every 'hot' pipe off cleaned it and checked the silicone joiners and they are all fine. If I adjust the bolt at the center bottom of the wastegate would that adjust boost? I haven't touched that yet simply because I was unsure what it does.

Il add some pics just incase

[The Real Roadrunner]

if its quieter than check for blockages in the exhaust.
dont adjust anything on the car yet as you may just bandaid the prob not fix it.
drop the system off after the dump and take it for a quick blat and see if you have your boost back. then if that doesnt tell you anythig maybe start fiddling with other stuff .
im thinking stuffed cat.

[BeRad]

yer agreed ^^^

where does your boost controller go ? the plenum or a cooler pipe, and where???

[EldarO]

What do u mean by loosened itself up??
The car is running fine, no idle problems, not running rich or anything, only thing is it wont go over 15psi.

It was fine at 19psi and held it nicely. I think it was just after cruising on the highway at night driving normally so it wouldn't have been hot but i didn't notice until I gave it some maybe the next day or something... I cant remember sorry..



Yeah it comes onto boost normally..

nah, what i meant was, that the wastegate might've been crusted up a bit, and not opening up the whole way, if boost control was erratic, would be possible, and running it for a while loosened it up, and now its working properly, kind of a long shot, but thought id ask.

the temp/running condition question was to see if anything happened that would cause the waste-gate to de-crust itself.

hope ive explained it?! i wrote it and cant understand what i said :|

Elmo.

[BeRad]

haha simialr to mondayitis

what wastegate is it? if its an ebay one maybe its reached its use by date, as "SOME" are designed very poorly.. pull the gate off and have a look maybe its jammed open or something? or the valve opens on the piss (not paralell to the bored hole).

[eighty-eight]

I'ts a greddy type R gate so its decent quality, this is the route of air from the inlet manifold to the boost controller to the wastegate..

from Manifold


blue hose if from BC, the 2 red are to the wastegate.


2 hoses to wastegate:

[The Real Roadrunner]

can you guys stop confusing this poor dude.
88 check the exhaust and let us know the outcome.

his car has the good gear its just somethings gone to poo, but only sounds like a minor prob.

[eighty-eight]

It was the cat, and im not the only one that has had problems with a metal cat.

[Endless]

That looks a bit nasty - metalcat's for the loss then eh..

How many other people have had this problem?