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View Full Version : Got to be boost leak, right?



T-spoon
08-15-2012, 03:11 PM
I was hitting about 1.5-1.6 bar, and then one day, it dropped to barely 1 bar, and now it's hardly hitting .4 I checked everything I could think of. The manifold and turbo connections are all solid, the wastegate is brand new (pulling all vacuum hoses from the wastegate doesn't change what boost it will build). No BOV (already removed because failed). I futzed with my only questionable IC piping connection yesterday and checked all the others. Everything seems solid.

But this still has to be a boost leak right? I don't have a tester or an air compressor at all for that matter, but I guess the next step is to get that and test the system. I suppose there could be leaky coupler or even the IC failing. Any other ideas in the meantime?

T-spoon
08-15-2012, 03:12 PM
I did wonder briefly about a clog in the exhaust, but the only thing in the exhaust is a less than 5k mile high-flow cat, and in any case I'd reckon it would take an extreme blockage to drop boost that much.

Ryan
08-15-2012, 04:19 PM
First thing that came to mind for me was leaking of some sort. But it seems like you have checked just about everything.

On the flip side of that, it could be a simple crack or hole caused by being too close to something hot..

How "old" is the turbo itself??

Intercooler is in good shape?


Sent from MARS! 👽

underscore
08-15-2012, 05:53 PM
cracked turbo/exhaust manifold allowing gases out? Or possible a damaged/jammed wastegate?

MrWOT
08-15-2012, 06:39 PM
Wastegate stuck open would be my guess. If it was a boost leak that big you'd be massively overfueling.

Facime
08-15-2012, 06:43 PM
^^This


if thats a knockoff wastegate, they are notorious for gumming up after a few thousand miles. As said a "boost leak" that big would show up in a big black cloud of smoke out the back and a noticable sound as it escaped.

Mafix
08-15-2012, 08:15 PM
did you actually look at the turbo wheels and see if there is anything left?

T-spoon
08-16-2012, 01:35 AM
Turbo looks fine (at least, intake side, minimal side to side play, zero in and out play, spins freely, fins are all in-tact).

It IS massively rich in boost. If I stay in the throttle and take it to redline the wideband readout plummets into the 9s. THis disturbs me so I haven't stayed in it enough to see just how much fuel is coming out of the exhaust :P

The wastegate is a genuine tIAL MVS and has less than 1000 miles on it. If it has failed I will be extremely disappointed. It's only a 38mm but my turbo is not ridiculously large (t67 I think) and the wastegate spring pressure is 15psi or so.

Intercooler is somewhat of an unknown.. it's a generic model that Driftmotion.com sells. I don't see anything from the outside that looks like a problem, but I doubt I would without pressure testing.

underscore
08-16-2012, 02:05 AM
Pressure test errything then.

Hookecho
08-16-2012, 05:39 PM
Do you have a boost controller? I had a filter clog on mine once and couldn't boost past 7psi. I think the paper filter collapsed in it or something.

Hookecho
08-16-2012, 05:45 PM
Also, I have a boost leak detector that i can ship you if it will fit you turbo.

T-spoon
08-16-2012, 07:31 PM
Also, I have a boost leak detector that i can ship you if it will fit you turbo.

Hmm, that could be super handy. My piping is pretty standard (2.5" I think?), so it would probably fit. I was going to go to the hardware store and make one eventually, but borrowing would be nice. The detector you have is essentially two plugs for the piping with an air fitting to hook to a compressor to pressurize the system?

I have boost control via the AEM v2 running an electronic actuator. I tried removing it from the system and then with no vacuum going to the wastegate at all and it didn't change anything.

Also.. I am down to like 1 PSI and can definitely hear a loud hissing from what may be the passenger side whenever I approach the vacuum/boost transition. I'm going to check the wastegate in the meantime and make sure it looks ok internally.

MrWOT
08-16-2012, 10:18 PM
Do a vac leak test with propane before you get too crazy.

Ryan
08-16-2012, 11:02 PM
^+1.

Could he use carb cleaner as well?? I know it works to spot leaky intake manifolds..


Sent from MARS! 👽

T-spoon
08-16-2012, 11:11 PM
Do a vac leak test with propane before you get too crazy.

Could you elaborate? My boost gauge and map sensor(through the AEM) are both reading strong vacuum - unchanged from when it was holding boost.

underscore
08-16-2012, 11:52 PM
If nothing else, take off the IC, cover the inlet/outlet with some tape, and stick it underwater.

Mafix
08-17-2012, 12:00 AM
just pull the booster vac line off and put a little air pressure in it. poof boost leak tester

T-spoon
08-19-2012, 05:46 PM
I think the ex manifold may be cracked. AFter driving the car for more than an hour it was quite hot and the hissing so loud and unable to get out of vacuum at all that at a stop I was able to rev the motor and narrow down the hissing to around the manifold, but it's not the wastegate or turbo connection. Looks like I'll have to take it off and examine it. I'd expect failure from a cheap tubular, but I have a cast, so it wouldn't have been my first guess.

MrWOT
08-19-2012, 06:19 PM
Could you elaborate?

Get a propane torch, and open the valve a little without lighting it and move it around suspected areas. Will cause the engine to idle up when you find your leak.

As for your crack, seafoam it and see if you see smoke coming out the exh.

T-spoon
08-21-2012, 03:31 AM
Well... the high-flow cat I put in about 10 months ago failed and clogged the exhaust. The loud hissing was ridiculous amounts of backpressure finding every little chink (in this case an unused o2 sensor plate with a tiny leak). I removed the broken up pieces of the cat and went ahead and did away with the rest too so it's a completely open 3" from the turbo back. Boost is back.. and how! 1.6 bar of tire roasting fun.

MrWOT
08-21-2012, 03:50 AM
the high-flow cat


IIIIIIIIIIIIIIIIIIIIIIIIIIrroooooooooonnnyyyyyyyyy !

Ryan
08-21-2012, 03:57 AM
^^ hahahaha


I'm glad you got it back up n running man! I bet it sounds like the gates of hell opened up!


Sent from MARS! 👽

T-spoon
08-21-2012, 03:58 AM
IIIIIIIIIIIIIIIIIIIIIIIIIIrroooooooooonnnyyyyyyyyy !

:hehe:

Facime
08-21-2012, 05:38 AM
wierd. I wonder if all the pre-tuning running around with it running rich led to its failure. I actually had a cat fail and clog the exhaust on an N/A and it took forever to figure it out.

T-spoon
08-21-2012, 03:36 PM
wierd. I wonder if all the pre-tuning running around with it running rich led to its failure. I actually had a cat fail and clog the exhaust on an N/A and it took forever to figure it out.

I wouldn't be surprised if that had something to do with it. I've also had some big KAPOWs that may have hurt it. I need to go to an 8 heat range plug at least with this much boost. Had precat fail and clog on the MR2 this last year, so it was kind of in the back of my mind as a possibility, especially when I had revs starting to drop in addition to the boost loss, but really it was the fact that taking off the downpipe is so much easier than taking off the whole manifold that led to discovering it relatively quickly.

ChrisD
08-21-2012, 11:51 PM
Wow. So it was a cat in the dp? Was it a SARD unit or one of the replicas?

Glad to see it's sorted now!

Sent from my SGH-T989D using Tapatalk 2

T-spoon
08-22-2012, 01:46 AM
Wow. So it was a cat in the dp? Was it a SARD unit or one of the replicas?

Glad to see it's sorted now!

Sent from my SGH-T989D using Tapatalk 2

Oh, no, the cat was in the midpipe directly after the downpipe. It was a.. magnaflow IIRC. There are really only 2 pieces to my exhaust, the downpipe and the rest of it. I just took the downpipe off first because I was going to remove the whole turbo/manifold assembly but decided to test drive it first without the downpipe on just in case it was a blockage.

Hookecho
08-22-2012, 09:14 PM
Glad you figured it out.