[Ferruccio]

I'm getting a weird problem with the vehicle. Basically, I have no boost sometimes.

Here's the lineup of events:

1: I had full boost, as far as I know, then turned off the engine for a few seconds a few minutes later.

2: This is when I discovered the problem. I had no boost whatsoever, and the exhaust was loud and throaty, much like it would sound if the wastegates are completely open. This did not get fixed upon switching maps back and forth or by restarting the car.

3: I parked the car, did some datalogging, found that no codes were thrown during those runs. I left the car parked for about 30 minutes.

4: I started the car up again and it seemed to have no boost initially. Then, about a minute later, it suddenly had full boost.

5: Midway through this run, I did another pull and experienced partial boost. Then, quite a few runs afterwards, I was back up at full boost.

So, tl;dr, My "full boost" is intermittent. My very uneducated guess as to what is going on: some hose is loose, or the wastegate actuators are getting stuck open.

Any ideas?

[JamesM3M5]

Those are my two first ideas. I have seen a turbo WG shaft so sloppy that it didn't allow the WG to close. The other idea is that there is a boost control problem on the vacuum side. Leaks, cracked hoses, or faulty WG solenoid.

[Ferruccio]

Originally Posted by JamesM3M5

Those are my two first ideas. I have seen a turbo WG shaft so sloppy that it didn't allow the WG to close. The other idea is that there is a boost control problem on the vacuum side. Leaks, cracked hoses, or faulty WG solenoid.

Yeah, so, hardware is finnicky, somewhere. I have no tools, so I'm going to have it looked at and report back in. Wherever the leak is (if there is one) I can't seem to find it. All my hoses look hooked up just fine. If there is a leak, it must be really small and intermittent.

I'm hoping that it isn't the wastegate, because then that would mean new turbos :S

[Ferruccio]

So, I am driving the car around some more, and I am beginning to think that it is a wastegate issue, possibly some sort of loose electrical connection, though I do not know the exact layout. Upon a cold start, it is not uncommon that I will not have boost at all, but, after a minute or so, I fully regain boost. I've felt boost leaks before, and those are usually *always* a loss of power. Mine comes back and behaves normally.

But, it also comes and goes. I floored the car at highway speeds in 6th, let off, then floored it again, and just a minute or two later, I had no more boost. But, just one minute later, I gradually had it back.

[Jeff@TopGearSolutions]

Does this remind anyone of the sticky wastegate problem? This is most common with those individuals that road raced and really heated up their wastegates/turbo components.

[Dmacc]

Originally Posted by Jeff@topgearsolutions

Does this remind anyone of the sticky wastegate problem? This is most common with those individuals that road raced and really heated up their wastegates/turbo components.

Happened to my car on a drive up a mountain road and I was pushing the car pretty hard, I accelerated on an uphill straight away and let off the gas only to realize my wg was stuck open. I had no boost and a loud drone. I was able to have my buddy jiggle it shut again, these stock wg are a headache.

[Ferruccio]

Originally Posted by Jeff@topgearsolutions

Does this remind anyone of the sticky wastegate problem? This is most common with those individuals that road raced and really heated up their wastegates/turbo components.

Well certainly drive like a pussycat most of the time, never making full boost until the engine is really warm. This usually means that I don't reach full boost for more than 3 seconds total during a work week (really short commute). The symptoms seem to exactly match those of a stuck wastegate though. I would *really* not want to have to replace the turbos because of this.

[Ferruccio]

Got the problem diagnosed! Thanks for FFTEC, the wastegate on one of the turbos is very much stuck on occasion, so there might be some kind of corrosion going on. I'm going to get it repaired/replaced.

[JamesM3M5]

They stick due to excessive wear on the shaft and in the turbine housing. Nothing but a new turbo will fix that.

[trbolexis]

fortunately, all these single turbo upgrades we've done, have made stock twins readily available!