Turbo is going Bizerk and overboosting....

[driftin8ez]

I was driving my car yesterday and the turbo sounded a lot more high pitched than usual. So i looked at the peak hold function on my blitz dtt and it said .89bar. WTF??? I usually never go past .75bar. I'm running a line from the outlet nipple on the turbo to the waste gate with no boost controller so it should be around 7-8psi. Today i replaced my waste gate line and used my boost leak tester to see if my pipes where leaking or something. The only leak i had was at the tb to intake mani gasket from when i installed the KADE TB. So i took it for another drive and now at like 1/4 it will shoot to like .88bar and will keep going up if i keep my foot in it. So what the heck is wrong. Also this has never happened before but today when i took off my maf to install the leak tester there was a mass amount of oil in the suction pipe. So WTF is going on? Is my turbo blown? It drives fine and doesn't smoke at all.

Mods:fmicfull 2.75" turbo backwalbro 255lphstock t25kaDE TBKAe MAf

everything else is stock.

[Logan76]

mine creeps to 11 psi when im at WOT, Im assuming its from my full 3" turbo back, and thats blow by, it could be from your turbo or it could be from piston ring wear, but expect a little blow by because im assuming you dont have a catch can installed? does it have any shaft play?

[driftin8ez]

very little up and down none in and out

[Logan76]

hmm, do you have a vaccum leak anywhere? that could cause your boost to go up? You probably have more knowledge than me, Im just shooting ideas.

[driftin8ez]

the only leak is a small one in between the tb and intake mani but im pretty sure that has been like that for a few weeks ever since i installed my kade TB. Also i've had the 2.75" turbo back for about 2 weeks with no overboosts until yesterday.

[Logan76]

what does .88 bar convert to for PSI? like I said with my 3" turbo back im hitting near 11psi and I run perfect vaccum, so if you consider your turbo back + your slight vaccum leak you may over boost a little.

[driftin8ez]

.88bar converts to like 12.5 psi. And thats only at 1/4 throttle. If i give it more gas it will go up more. Like may waste gate isn't working. But i ran about 5-6psi through the waste gate line and it opens just fine.

[Logan76]

Oh snap, I didnt know it would continue to overboost, sheeeit. It may be your wastegate sticking? I dont really know what to tell you other than best of luck.

[driftin8ez]

well it seems like it will keep boosting i never really kept giving it gas to see but i will tell that my turbo gets really high pitched when it starts going that high and it never sounded like that. Also i can move the waste gate with my hand and some force.

[Logan76]

Yeah, you should be able to move it with your hand, so I got no clue, bump for you.

[c-rad]

mine creeps to 11 psi when im at WOT, Im assuming its from my full 3" turbo back, and thats blow by, it could be from your turbo or it could be from piston ring wear, but expect a little blow by because im assuming you dont have a catch can installed? does it have any shaft play?

Blow-by won't have an effect on the level of boost being run. Creep is caused by a faulty wastegate or too small of a restriction in the exhaust. That's about it.

[Logan76]

I was refering to him saying about the oil in his intake.

[c-rad]

I was refering to him saying about the oil in his intake.

Ahh my bad.

[driftin8ez]

Well i took it out again and it seems like it will spike to about 12-13 psi then go back down to 10. Still way higher that the 7-8psi I'm used to running. Im going to see if i can find a TB gasket tom. and see if that brings me back down. The only thing that has me worried is the high amount of oil i had in my intake and the turbo is now higher pitched. Hopefully thats just from the higher psi.

[Logan76]

Higher psi = louder turbo.

your still probably going to spike to around 10 psi.

[float_6969]

It could be that the actual wastegate actuator has failed. There is a rubber diaphragm in there and if it's failed and leaking, you'll run more boost than normal.

[BACARDI_DWB]

i agree with float. also i would check the line running from your wga, it may have a small pin hole leak that would be bleeding off. you may not even beable to notice it. just replace it and see if its still doing the same thing. is it holding that boost thru the whole spool or just up top?

edit. sorry i just realized you already replaced that line. your wga is probelly dead. those diaphrams crap out like float said

[driftin8ez]

It could be that the actual wastegate actuator has failed. There is a rubber diaphragm in there and if it's failed and leaking, you'll run more boost than normal.

Thats sounds about right. Im going to test that tomorrow, Im just going to shoot air through a vacuum line connected to the wg and see if i can hear leaking and also see how long it holds the pressure.

[Bwana]

It pretty much has to be your wga if the wastegate isn't stuck.

[driftin8ez]

Ya i going to check it first thing sunday. Also and sr t25 wga should bolt up fine if i deem mine to be doa right? The sr wga is set to 7-8 psi stock right?

[Logan76]

Yes it is, I belive 7 psi.