throttle body boost leak

[max-89supra(t)]

i did a boost leak test on my car today and only found one major boost leak- it was a huge boost leak coming from the bent tube coming from the throttle body going to the valve cover hoses.

has any one had the same problem? is there an easy way to fix this? i hope i dont have to get a whole nother tb.:nono:

 

[gaboonviper85]

Lmao....silly man you're suppose to cap that off before boost leak testing!

Ofcourse it's a boost leak...look how the system is designed...it's a control'd boost leak when it's all plumbed up correctly behind the afm.

I sure as fuck hope you didn't pump much air in your system cause what you just did can blow all your main oil seals such as rear main, front main, cam seals, oil pump driveshaft...I seriously seriously hope that didn't happen...happened to a good friend of mine!

 

[max-89supra(t)]

controlled boost leak?

it couldnt have blown the seals cuz i disconnected that pipe from the valve covers.

how could it be a controlled boost leak? it leaks like crazy and i cant even get a few psi to hold for a few seconds and its just leaking from that one spot. is there a valve in the throttle body? any way it could go bad?

 

[89supra7mgte]

its controlled because the air flows back and forth from accordion valve covers and tb. but is still circulated and it is still air that has been meetered. Is it coming out of the end of the tube or where the tube meets the tb?

 

[gaboonviper85]

controlled boost leak?

it couldnt have blown the seals cuz i disconnected that pipe from the valve covers.

how could it be a controlled boost leak? it leaks like crazy and i cant even get a few psi to hold for a few seconds and its just leaking from that one spot. is there a valve in the throttle body? any way it could go bad?

No it can't "go bad"....it's how it's supposed to work but you're supposed to plug it before testing or else you'll pump compressed air into your block which is badnews bears! I'm horrid at explaining the science behind things but it is supposed to work this way. Get a rubber cap to fit over the pipe on the throttle and leak test again.

It is a boost leak but the air never exits the system so it's a controled leak so to speak...kinda the same as the stock blowoff valve/bypass valve (it's plumbed the same and stops the motor from running rich for that moment upon blow off..

 

[89supra7mgte]

how are you running your boost leak test?

 

[kamikazemkiii]

piks?

 

[jetjock]

PCV system orifice. Time to RTFM...

 

[max-89supra(t)]

PCV system orifice. Time to RTFM...

what do you mean??????

and ya ill post pics of the tester i made- first i tested the the pipes and ic by themselves, held fine, then i tested from the tb, ill post pics asap.

 

[max-89supra(t)]

No it can't "go bad"....it's how it's supposed to work but you're supposed to plug it before testing or else you'll pump compressed air into your block which is badnews bears! I'm horrid at explaining the science behind things but it is supposed to work this way. Get a rubber cap to fit over the pipe on the throttle and leak test again.

It is a boost leak but the air never exits the system so it's a controled leak so to speak...kinda the same as the stock blowoff valve/bypass valve (it's plumbed the same and stops the motor from running rich for that moment upon blow off..

never exits the system? dude its letting compressed air out into the accordian hose which doesnt hold pressure!! do you think the whole system is pressurised from the air filter back? lol now im lmao

 

[gaboonviper85]

never exits the system? dude its letting compressed air out into the accordian hose which doesnt hold pressure!! do you think the whole system is pressurised from the air filter back? lol now im lmao

You don't get it....although your simple mind is having a hard time comprehending and in that you are being a smartass but I'll try to explain...

The afm is BEFORE the pcv port in the accordian hose....while at idle that port will see vacume as it's plumbed behind the throttle, yet the afm is still reading the air as the port "again" is behind the afm....while boosting, the flow path changes direction in the pcv hard pipe as now the intake has pressure and the accordian is not....this cause the pressurized air to blow back into the accordian "again" behind the afm....now here is the tricky part....the turbo is sucking even more air than that "boost leak" is leaking so the direction of the air stays in the direction of the turbo (turbo keeps sucking in said boost leak.....keep in mind that all this is happening "behind the afm"....all the air stays contained in the system and just continues to loop over and over....but the turbo sucks in much more air than what escapes out the throttle and all the air that the afm reads does get burned "eventually" and the ecu is tuned for this!

Our pcv system runs on the Venturi effect....google it.

The air is metered....it never escapes...it does get burned...they system is contained within the intake system itself....it is not a boost leak...it is not problem...

Do you understand now????

 

[max-89supra(t)]

these are the simple adapters i made to do a boost leak test:

the first adapter i made out of a pvc pipe plug (you can get at lowes or home depo) i drilled a hole in the center and put a regular wheel inflation valve(make sure to get one that has a rubber gasket) and tightened it with the nut that came with it. then i put it in a rubber hose thats big enough to fit on the intake side of the turbo(where the accordian hose goes). put clamps on both sides of the hose of course. the second pcv plug is to put on the intake pipe the one before the throttle body- this will test you pipes and ic- should hold pressure without losing any at all.

warning- carefull not to overpressurise as it is very easy to with this setup, i would inflate just a little at a time and would check with a gauge constantly.

when i was done doing that test i then took the tester i make and put it on the throttle body-its the same diameter as the turbo inlet. i opened the oil fill cap and disconnected to j-tube on the tb for safety and found that it would leak like crazy the second i put any pressure in-this seems like its way too big of a leak, some say it should leak like that, but isnt that loosing boost?????????????

 

[max-89supra(t)]

You don't get it....although your simple mind is having a hard time comprehending and in that you are being a smartass but I'll try to explain...

The afm is BEFORE the pcv port in the accordian hose....while at idle that port will see vacume as it's plumbed behind the throttle, yet the afm is still reading the air as the port "again" is behind the afm....while boosting, the flow path changes direction in the pcv hard pipe as now the intake has pressure and the accordian is not....this cause the pressurized air to blow back into the accordian "again" behind the afm....now here is the tricky part....the turbo is sucking even more air than that "boost leak" is leaking so the direction of the air stays in the direction of the turbo (turbo keeps sucking in said boost leak.....keep in mind that all this is happening "behind the afm"....all the air stays contained in the system and just continues to loop over and over....but the turbo sucks in much more air than what escapes out the throttle and all the air that the afm reads does get burned "eventually" and the ecu is tuned for this!

Our pcv system runs on the Venturi effect....google it.

The air is metered....it never escapes...it does get burned...they system is contained within the intake system itself....it is not a boost leak...it is not problem...

Do you understand now????

ok thanks for explaining, hope your right. and i was only being a smartass cause you were being one, i know that i dont know everything and when i come here for help i hate being put down, or made fun of, sorry and thanks for the help.

 

[gaboonviper85]

I was not being a smartass in my previous posts...have no clue why you say that...I was being as straight and helpful as I could...

And yes I am right as it is just simply how Toyota designed the system...and the system works! It also has room for improvement but that's another topic for another day.