EVOLUTIONIZE

Last night on my way home from school I decide to do a wot pull on 5th gear. My boost is spiking up to 24.2-18.9 By redline Normally. But this time it went as high as 27psi so I let go right away. I get to the light and do a rolling 1-2-3rd run. Now boost doesnt go over 19psi no matter at what load I go at it. I get to a gas station and pop the hood to look for any loose vacuums or couplers nothing unusual. 10 min later boost doesnt go over 17psi.. I go home and a buddy brings his Boost leak tester we hook up the Air compressor to it and the boost gauge doesnt go over 2 psi. We were sending 50psi worth of pressure and we couldn't hear one damñ thing. All the pressure ended up going out through the exhaust . But how is this possible, In order for that to happen an intake valve and an exhaust valve have to be open at the same time for pressure to circulate correct me if im wrong? So I do a compression test and get 170-171psi across the board. So they seem to be fine? I tried it in a different position but only once more and it did the same thing. I shoulve kept rotating the engine in just in case ;(?? I am running out of ideas and my desperation is blocking oxygen to my brain lol.. Any suggestions will be greatly appreciated.


Thanks
Joel

EVO8LTW

iTrader: (41)

Geez...I thought you had hurt the motor or something with the boost leak test based on your subject line. I would just cap off the upper IC pipe so you aren't pressurizing the crank case with your test and so you don't have to worry about turning the motor to a specific position.

EVOLUTIONIZE

I'll try that today when i get back home and divide piping into sections in case i dont hear anything . The funny thing is last week we did a boost leak test and boost gauge went up to 25psi and it was holding pretty good. That was after finding out the Type-S Diaphragm had a hole in it. Im thinking if the EGR failed to close could the pressure be going out trhough there and back into the exhaust? Usually when ive experience a boost leak in the past the car gets really rich and cant hardly move or get any positive pressure. In this case i reach around 17 psi but no more than that .. Unless my wastegate flapper got loose, Weld broke? Lets say that will explain the reason i cant go past 17psi.. The air coming out trhough the exhaust on a boost leak test got me all confused.

Fourdoor

iTrader: (11)

There are is a small amout of time during the crank revolution when each cylinder has overlap between the exhaust and intake valves being open. When you shut off the engine it just happened to stop at one of these times. Bump the starter and re do the boost leak test and it should work fine.

Keith

EVOLUTIONIZE

I'll deffinitely try it again , there were a couple of things i did wrong. Also it looks like with one of the boost leak tests one of the hard to reach vacuums from the EGR got loose so now i get the p0140 code .

Thanks again

Joel

matt55

iTrader: (12)

Was your motor warmed up or was it cold ?

EVOLUTIONIZE

The motor was cold. I segmented the pipes as suggested and found a boost leak where the J pipe meets the turbo. The small metal gasket is rusted one side. Fixed that boost leak put eveyrting back i went for a drive and same thing no more than 12 lbs. That wasnt the real problem. We tried taking out the boost controller and boost went up to almost 30 lbs we let the vaccuum from the wastegate open.. but with a boost controller open or closed 2 diferent boost controllers were tested the car will only reach 12 lbs. I took out the wastegate to chekc it out and it looked good, what is the right method for testing a wastegate? Sending pressure to the nipple it should open by itself?? My wastegate will only work comepltely open or ocmpletely closed nothing in between. Could the wastegate be bad?

theblue

iTrader: (1)

wait a minute... WTF are you people talking about... unless somebody was pressing on the gas then the throttle body should be fully closed. So how is air even getting into the engine when you're doing a pressure test? no way you should be able to feel the air escaping out the exhaust.

matt55

iTrader: (12)

I have had better luck with the motor warmed up , it seem that it seal better for me at least.

+30psi with NO boost line going to the WGA is normal

+/-12psi with NO boost controler (ie vacum line from intake mani to WGA) is normal

if you have the stock boost controler set up you might be missing some parts to it (ie that brass pill) , but i done forgot how thats set up so i cant help there .


the blue
the TB is never 100% closed air tight

SuperHatch

iTrader: (23)

Even with the throttle plate close air still gets into the intake manifold. It makes it through the IAC circuit. How do you think you car idles with the throttle closed?

- Steve

EVOLUTIONIZE

No i dont have any of the stock vac lines and the solenoid is just plugged to avoid a CEL. The car was working perfect 2 weeks ago. I have a turboXS boost controller i already checked the BC i opened it up and it wasnt clogged but just in case i cleaned the heck out of it . Thats what i tried to say open boost it does what its suposed to.. And directly from the turbo works good also 12psi.. But with a boost controller In place it will only boost 12 lbs I tried adjusting it up or down i also tried switching the vacuums at the BC . I also tried a different boost controller. Andthe connection was perfect. as this was how i had ti setup before the problem started happening.

(How it all started)
I was boosting 25 psi 19 to red line . But the other night for some reason it went up to 27psi. so i let off. when i get to the light I go at it again and its not 27psi spike anymore and its not 25psi (original setup) neither. It goes to 19psi.. So I' keep trying and now its 15 psi. i go to a gas station to check fo boost leaks and everything looked good. So this is how the boost leak test thread started. The problem was never a boost leak even 5hough i found a small boost leak but not enough to make the car not go over 12 psi.. That has been fixed. Im guessing my wastegate got messed up.

matt55

iTrader: (12)

25psi !!!!!

hmmm.....
The wastgate sounds like its working fine (30 psi no input and 12psi no BC stright vac line)


Its sound like the MBC is not closed all the way , or the spring falled . Something in that system is letting boost seep bye befor you want it to .

Put a hose on the vacum side of the MBC and check for leaks (ie blow on the hose)

I know this sounds dumb but make sure that the MBC is not hooked up backwards

Good luck with it

EVOLUTIONIZE

The car was working fine connected as it is before it happened. But i did try 2 different boost controllers and i switched the vacuum lines on both with the same results. I checked the wastegate nipple and also the J pipe nipple for obstruction and found nothing. all vacuum lines were also replaced (NEW) I alo ended up taking appart the turboxs and it was fine. The only thing left is the wastegate I'll try to get a hold of one from a friend who replaced his turbo and I'll get back with results. Thanks for the tips

Joel


That was on 100oct

TTP Engineering

iTrader: (465)

Bring the motor to TDC first.

3deep

iTrader: (4)

How is your mbc plumbed.Try connecting between wastegate and lower
intercooler pipe.What is your vacum reading on your boost guage.Stupid question,is the car actually slower.Maybe your boost guage is bad.