Ok so here is the scenario.

Turbo has been spooling fine until yesterday. Suddenly after a pull it wouldn't spool beyond 3psi. I checked the turbo, and there is no damage to the fins, no shaft play, and it spins freely. Looked the manifold over, and no cracks on the top side. I've never heard of a InlinePro SS cracking anyways. There is an odd sound when I push into the range where it would spool. Very hard to describe the noise. There is also a sound almost like an exhaust leak when I smack the throttle. I have checked all the piping and it is not that. All the bolts are in the turbo to the manifold. I haven't had a huge amount of time to look the system over, but I was just wondering if someone had experienced a similar situation and could point me to some places to check. It is externally wastegated.

P.S. Engine runs fine. Idles smoothly and sounds sounds fine through the RPM range.

 

maybe the fire ring in the wastegate is missing/blown.If you hear exhaust when you should here spool, than its an exhaust issue.Look for black soot anywhere, that will tell you were its leaking from.And it will only get worse when there is more exhaust gassses moving threw the system.

 

I'm assuming the easiest way to check this is to remove the wastegate to visually inspect it. Where is the firering? Are you talking about the gasket with the metal ring in the middle that sits between the wastegate and the manifold?

 

boost leak.........check all your couplers on the charge pipes for splits or rips/cracks. they can sometimes be very hard to see since visually looking at all the couplers can be difficult depending where they are located.

 

the fire ring is that silver circle metal ring that sits at the bottom of the wastegate and the flange.

 

Thanks for confirming. Checking on that during lunch lol.

 

well if it worked fine before, then the fire ring is most likely there and fine. it is most likely a boost loak triple check your chare piping and couplers.

 

Does your BOV still sound as loud? Thats a big indicator of a boost leak.

 

No BOV noise at all which struck me as highly odd since it used to even make a sound at 1psi. Hoping its just a large leak somewhere. I was sure my turbo was cooked lol

 

check your chargepipe couplers. theres a leak somewhere

 

Listen to this guy, he's right It's a boost leak, a charge pipe has popped out of the coupler and is resting against the lip of the pipe, close enough that the turbo can still make SOME boost but most of it is leaking past the edges of the coupler. Either that or a coupler is torn, or your BOV has come loose, or something. You're going to hurt your turbo if you keep overspinning it like that.

 

Ok taking it all apart after work today.

 

I've had this problem with 2 different outcomes. The easier of the two was a simple boost leak. The coupler wasn't "off" but it wasn't sealing properly. The second time, some junk got into my oiling system (not sure how, but i have my theories ) and screwed the bearings in my BRAND NEW S256 which had to be rebuilt.

Hope for the first option...

 

If the bearings were toast wouldn't there be significant drag when I tried to spin the wheel?

 

Collin, Check the Intake air temp sensor. I tried to call but your mailbox is full. I just saw this.- Steve

 

You have an exhaust leak pre-turbo. weather its a stuck wastegate or a blown gasket just determine that bye process of ilimination. the obvious and easy is to pull the waste gate and visually inspect the gasket and fire right for black exhaust marks where a leak would occur. then from there reinstall and check the gaskets from manifold to turbo with engine runnign rev it up you will hear the exhaust leak on decel most certainly. What wastegate are you running?

 

Will do. If your talking about the boost cut setup before the motor warms up it's not doing that. I will have to hook my Tunerview back up. I kept running into it resetting, and it was just pissing me off so I haven't been using it for awhile now.

I am using a Tial 38mm

 

The Tunerview resetting may have something to do with finding the proper power source for it (it needs a source of power that does not cut when cranking) or you could do what I did and find a source that is turned on/off by hand. In my case, I have mine coming off a spare output on my fuseblock that works with the headlight circuit.

 

did your turbo previously use an internal waste gate?

i had the same issue when my tack weld broke that held the OEM WG flap closed on my holset


it still built 10psi off antilag tho.

 

His tunerview has to do with the actual connection at the data port.

No, I wasnt referring to the cold-cut, I was literally saying check the IAT sensor to see if it has somehow come out of the charge pipe or destroyed the coupler. If you dont find it tonight, call me tomorrow morning around 8:30-9am and I will walk through it with you.

 

I know what your talking about now. I had rotated it to hide it forever ago, and almost forgot about it. I'll look for it as soon as I get off work. Thanks for thinking of that.

 

IAT sensor is still there. Sitting just like it always has been.

 

If it has a flex pipe in the ex.. Check and make SURE the insides havent imploded on themselves.... Seen it more than once

 

X2

 

No...it doesn't mess up the bearings to the point of seizing. My turbo would spin just fine and show no noticeable problems, but once it got into boost (aka spun faster) it would come out of balance and lose speed when the wheels clipped the housing. It wasn't even that loud...it just made .6psi and no more. If yours is less out of balance, it could spin a bit faster before causing an issue.

I doubt this is whats wrong, but figured i'd chime in with my horror story