Could be westegate stuck. Check out this thread ko3 wastegate actuator replace

With boost leak you`ll probably get in limp mode and 4psi limit, not like this...

 

Could it be a bad N75 just failing to allow the wastegate to close? I'm not having any overboost issues (obviously), but it seems that on deceleration, vacuum sometimes goes to 24-25 in. I'm thinking it's a bad N75, which would be awesome, because the part is only like $50 and I can install a new one in less than 20 minutes. . .

Only thing is, if that's not what it is, I'm looking at more expensive repairs, and I'm out that $50. . .

 

Checked the wastegate actuator, the rod is moving as it should, but I just can't seem to get any boost. . .

I did notice that as the RPM's drop, you can see the wastegate rod "pulsing" in and out rapidly, and there is a noticeable rattling noise.

I think tomorrow I'm going to pull the cat off of the turbo and take a look inside, see if there's still a flapper door in there at all, if it's damaged or failing to seal properly. Could the minor exhaust leak have any bearing on the problems I'm having? The leak is after the turbo (the factory connection where there are 2 clamps on a slip-on type connector there), and it's relatively minor.

Honestly, a lift would be extremely helpful in diagnosing this. Then I wouldn't be rolling around under the car so much.

 

Well, I have been doing some reading. . . Turns out the old DV was installed reversed (vac line to intake manifold facing sideways instead of straight up), and the factory crimp-on hose clamps were replaced at some point along the line with standard screw-type clamps.

Also, I decided to narrow it down a bit further, see if it were possibly the N75 that were causing the problems. . . It's not. It's definitely an issue with the wastegate actuator assembly or the wastegate flap itself. . . I'm going to pull the exhaust manifold tomorrow (and replace the gaskets as well) to check it. Hopefully it's something as simple as just adjusting the nut on the wastegate actuator rod, I really can't afford to replace the turbo right now.

I also noticed there is some oil leaking somewhere under the car, I'm going to see if I can figure that out too. It's not leaking a lot, just enough that there are a couple of drips hanging from the bottom of the oil pan. I can park it overnight, and when I move it 24 hours later, it doesn't leave any drips on the ground, so it's really no big deal, but it's one of those things that I'd like to get taken care of. Still have to swap the CV axle as well.

I'm going to stop driving the car until I get this fixed, I'm afraid of damaging anything else, I just want to get this thing running right before my trip on Friday.

 

And exhaust leak hardly, no way with symptoms like this. I had whole exhaust flange next to the turbo fell off, but it was boosting, uh that was loud... Vacuum is fine, when I let off the pedal in gear it goes to 25inHG too, in idle is 20inHG.

Don`t know about n75, try to test it somehow...

 

Checked it, even with the N75 unplugged, it does the exact same thing. . .

Looks like I need to pull the turbo. Dammit. I'm REALLY not looking forward to that, I don't think I'll be able to get this done before Friday. None of the local parts stores stock gaskets for the turbo or exhaust manifold, so I'd have to order them. I can't really leave the car disassembled until the new gaskets arrive, so I'd be waiting until at least tomorrow to pull it all apart. I don't really want to take the car on a 4 hour trip without verifying that it's going to last, and it would suck to develop a problem miles away from the tools I'd need to fix it. . .

 

Forgot to add, it seems to have some "boost creep" too, if I give it a little throttle, the vacuum will go from 20 in to about 15, and even while holding the throttle there, the vacuum slowly increases to 16-18 in.

 

Yes, as rpm rises with same throttle applied, vacuum increases.

 

I meant that if I keep the RPM's steady, vacuum is increasing. . . Shouldn't the car make the same amount of vacuum the whole time the engine is kept at 1500rpm? I didn't think the vacuum would increase if the engine speed was being kept steady.


Wanted to throw a quick update here for you guys, I ordered a new exhaust manifold gasket and manifold to turbo gasket. I'm pulling the manifold off to get at the wastegate actuator and see if it just needs adjustment. If the adjustment is alright, I'll be forced to pull the turbo, which can be taken care of next week if I can't get it taken care of by tomorrow evening.

I just want this car to run as it should, I'm starting to get frustrated, but I do understand it's been neglected a bit more than I originally thought it had. Once I get it all straightened out, I think I'll be happier with the car.

I still want an AWD though, and I've been drooling over a couple of Subaru WRX's for months now. . .

 

Still have no boost. . . Adjusted the wastegate linkage, but I think I did it wrong (didn't take note of where the wastegate rests at idle), and it's still stuck open a little bit.

I'm just waiting for the engine to cool down enough now, and when it's done, I'll get going on it again. . . I WILL beat this problem TONIGHT.