2005 Lack of Boost

Hello,

This is a continuation of the process to rid my 2005 Legacy gt 5AET of its problems.

To start off, I bought a 2005 legacy gt with 140k miles with little knowledge of its defects. It drove and shifted fine, however, what I did not notice is that there was a lack of power (my old car was pretty slow so I guess I was used to it) and once the car was revved up to around 4k rpm the engine would stop increasing speed and acceleration was stopped. One of the problems turned out to be a seized wastegate which I assume was causing the ECU to get confused and cut fuel when it got towards 4k range (car could redline when in neutral and park but under load, it had this problem). Now that the wastegate is freed, I have a bit more power and the engine now goes past the previous limit. I am still chasing a good amount missing psi from the turbo. The turbo has little to no shaft play and makes no unusual noises whatsoever, but, there is quite a bit of misalignment on the turbo wastegate which is most likely either the cause or aid in the boost error along with deteriorating or leaking components involved with the turbo.

In an attempt to regain the lost boost, I am prepared to replace/ repair the following and would appreciate the advice and/ or guidance through the process:

Turbo inlet - the one currently in the car is more or less falling apart, there is a lot of grime coming from the connection between the inlet and turbo which I believe was caused by an inefficient PCV valve which was replaced.

Realignment of wastegate- when checking for shaft play I noticed later from photos the wastegate is missing the intended placement by a large margin causing a large gap.

Vacuum lines - since the car is old I assume its a good idea to replace these.

Uppipe to catless Uppipe - this one is less necessary, but I wanted to eliminate the possibility of the cat coming apart and destroying the turbo.

I will be posting logs and other photos later corresponding to the problem.

I changed my inlet last weekend. It solved my boost problems and af learning values. Really wasn’t a fun install. Prepare for some busted knuckles and frustration lol.

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Replaced your turbo inlet? Manifold on or off?

Manifold on

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That was actually one of my questions as far as how to go about replacing the inlet. I have the manifold gaskets ready in case I need to remove it, but, since I have to realign the wastegate I will be removing the turbo. Would it be easier or possible to put in the inlet while keep the manifold on without the turbo in the way? I bought the OEM inlet so I'm pretty sure I will need to take off or at least lift the whole thing.

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Also I was wondering if anyone has been successful with the wastegate realignment process. There's a post I saw somewhere on here about it, but the heating and banging seem prone to warping the housing.

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Wastegate flapper is off. I've fixed a few, but I've tried many, and it's a pain in the ass to do. It doesn't warp the cast iron, but it does beat up on the weld holding the actuator arm pretty good.

I have new exhaust housings but you have to be extremely careful when you remove the old one. They are usually on extremely tight and if you're not very careful, you can bend blades on the turbine.

Wastegate flapper is off. I've fixed a few, but I've tried many, and it's a pain in the ass to do. It doesn't warp the cast iron, but it does beat up on the weld holding the actuator arm pretty good.

I have new exhaust housings but you have to be extremely careful when you remove the old one. They are usually on extremely tight and if you're not very careful, you can bend blades on the turbine.

It sounds like the realignment is not as straight forward as I thought. I am interested in the exhaust housing because I'm not too confident in metalworking. Also, would it be expensive to get a new turbine wheel? Since the turbo is quite old it would be a shame to do the work of replacing the exhaust side if the turbine itself goes out in a couple thousand miles.

If the turbo isn't totally blown you may want to hand it over to a specialist for a rebuild instead.

Or get another turbo and trade in the old as a core.

If one thing is quirky, then it may be other problems around the core.

If the turbo isn't totally blown you may want to hand it over to a specialist for a rebuild instead.

 

 

 

Or get another turbo and trade in the old as a core.

 

 

If one thing is quirky, then it may be other problems around the core.

That may be the best option

I just replaced the turbo inlet and while there was little to no shaft play, but, there was quite a bit oil in the inlet and intercooler.

I could get another one and try my hand at modifying the old.

I finished replacing the turbo inlet and it was much lengthier than anticipated. The intake manifold was lifted and all the hosing was a pain to get back into place.

Unfortunately, the boost leak is still present along with the knocking. The old turbo inlet was pretty torn up but I have the feeling it may be my turbo that needs to be replaced based on the amount of oil in the intercooler and all over the mangled turbo inlet. The only thing I see that has changed is the AFR tables.

Well, at least I know the inlet is not the problem so I will continue to search for the lost boost. I know the wastegate of the turbo is a large cause of the problem but im not sure exactly how much boost error that would cause or there is another issue aiding to the problem.

Any recommendations on other things to check in search of the missing boost?

Here are learning tables and logs: https://drive.google.com/drive/folders/1zLWSINUqGcT84QycYFedqY4HuWhdNASt?usp=sharing

Also, the ECU was reset during the replacement process so I waited until the IAM was at 1, but, I'm not sure if that would skew the data.

before inlet.csv

after inlet.csv

The problem has been fixed! The turbo was removed and replaced with a newer one and a catless uppipe was installed. I thought the turbo inlet installation was difficult lol. The uppipe was custom made by some shop and the connections lined up, however, the pipe was slightly shorter than the original causing the turbo to be mounted at a slight upward angle. This made realigning the inlet, oil lines, and downpipe very difficult. Also, the uppipe required hex bolts which were very difficult to grip enough to torque down. With enough working of the components, I somehow got everything to fit. There are no leaks that I can see, but there is a strange plastic smell that been coming from that area so I will need to look into what that is.

It turns out the wastegate of the old turbo was misaligned to such a great extent that it was rubbing the closest side of the hot side housing causing it to seize open. So, not only was the wastegate misaligned, it was also stuck open causing the majority of pressure to be lost from the turbo.

After driving the car so long with little to no boost, its crazy how much work the turbo does. The knock correction and problem has been just about eliminated and the AF learning tables are looking more within the accepted values.

The only problem I have now is getting the engine code to go away because the uppipe is now missing a sensor. I read you have to reflash the ecu to disable the codes. Does anybody have any advice on how to do this?

I will post logs and the learning view later, but, for now I will work on the torn cv boot and knocking sound that comes from cylinder 3 when idling every once in awhile.

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Good find on the waste gate :-D

Research EGT delete.

You can put a resistor in the end of the connector to simulate the EGT probe that used to be in the up-pipe and tape it up well to protect it.

I did something like this:

https://legacygt.com/forums/showthread.php/unofficial-05-06-lgt-2-2k-5w-resistor-up-pipe-131488.html

Good job sticking to it and fixing your problem!

I wonder how your wastegate got that bent in the first place. That's crazy.

The resistor fix is easy if you don't have a tactrix cable or an AccessPort.

If you have a tactrix cable then disabling the code is as simple as clicking a checkbox.

I'm not sure how to do it with an AP.

Thank you to everyone who helped me through this process because there's no way I would still have this car if I had to pay a shop to do everything I found. After 3 or 4 months, I can finally enjoy the car.

I do have a $12 VAGCOM cable I got a while back that works pretty well for logging and checking engine codes, but, I don't trust it to not brick my ecu if I reflash it. I ordered some resistors because apparently, no store in my area has them in stock.

I found the plastic smell was the top oil line leaking a bit onto the very hot uppipe so I also ordered some more crush washers.

Here are some logs and the learning table I took this morning:

https://drive.google.com/drive/folders/1HOvGnm-6Xu6wmsyRaHZZNhUCVBmOYsRh?usp=sharing

There was I little bit of correction in the one I accelerated a bit. Not sure if its something to worry about, but, the learning tables don't show any correction and a knock count of 3 is a lot better than the 20-30 I was getting prior to the new turbo.

Im trying to learn as much as I can about this car so I am considering purchasing a tractix and getting into some basic tuning so any resources on guides on that would eb appreciated.

Good job sticking to it and fixing your problem!

I wonder how your wastegate got that bent in the first place. That's crazy.

 

The resistor fix is easy if you don't have a tactrix cable or an AccessPort.

If you have a tactrix cable then disabling the code is as simple as clicking a checkbox.

I'm not sure how to do it with an AP.

Wastegate flapper isn't bent. The bushing that holds the wastegate flapper shaft moved upwards in the cast iron exhaust housing. They can be a real bitch to put back into place, but as I said before, I've been able to do a few and have tried many, and generally, it wrecks the weld on the flapper shaft arm from having to hammer it while almost the entire housing is red hot. Once you have it back into place, then you have to drill out the old roll pin and over drill the hole and put a new larger roll pin in.

Definitely not worth the effort unless it's all you have.

Wastegate flapper isn't bent. The bushing that holds the wastegate flapper shaft moved upwards in the cast iron exhaust housing. They can be a real bitch to put back into place, but as I said before, I've been able to do a few and have tried many, and generally, it wrecks the weld on the flapper shaft arm from having to hammer it while almost the entire housing is red hot. Once you have it back into place, then you have to drill out the old roll pin and over drill the hole and put a new larger roll pin in.

 

Definitely not worth the effort unless it's all you have.

I'm glad you let me know, I was about to destroy the wastegate lol.

I still have the old turbo and Im going to try to rebuild it a bit and maybe look into putting a bigger wheel or something if I can get the right equipment and resources.(mainly just to mess around and learn about the turbo, it most likely won't be going into a car) Also if you want the old exhaust housing let me know or if you have new housing I would be interested.

I took a quick log in 2nd gear to make sure everything was looking alright. ( I would do 3rd but I don't have a log enough straightaway) If anybody sees anything concerning let me know

https://drive.google.com/file/d/1AZIjlQdVk7TSpZ0F17xYoM-C0bkp3uV9/view?usp=sharing

So an update, There is quite a bit more boost than before and the replaced turbo has been working fairly well, however, the peak boost seems to be around 8-10 psi according to the boost gauge recently installed which is a bit below the target 13.5.

Under heavy boost there is exhaust smell inside the car and a slight whistle which points towards an exhaust leak.

During the process in which I replaced the turbo inlet I tore the 4mm line that contains the restrictor pill on the turbo. Instead of buying a new one I just took a length of tubing roughly the same size and put the restrictor pill near the middle via a thin pick. The pill does seem to slide around a bit an seeing as the pill determines wastegate actuation there may be something wrong going on there.

There's a hose which is cracked that runs from the brick up into the side of the intake manifold. This could be somewhat related if manifold pressure is leaking from the intake system.

The current plan is to tighten down the uppipe, replace restrictor pill line and replace bov and turbo to intercooler gaskets just in case. I feel a boost leak test could also be useful in the search for the missing boost.

Vaccum lines and turbo lines other than those mentioned seem to be secure.

Another sort of unrelated issue is there seems to be a new tapping while idling coming from cylinder 3 (not rod knock). I know the sound of the injectors but this is deeper, more internal to the engine. Could this be piston slap or incorrect valve clearance? I will post a video later.

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Here is the sound, its deeper than the injector tap and sounds more internal. Its best heard around 0:06

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When I had a tricky exhaust leak I put my shop vac in blow mode. Stuck the hose in the tailpipe and went to every connection w a spray bottle

of soapy water. Make sure to clean out the shopvac before you do this you don’t want to blow any debris up there

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I finally got to take the wheel off and check the connections. The uppipe to header gasket was leaking. I found the bolts to be pretty loose and I torqued them down, however, when both bolts were tightened I could see a small gap on both sides of the gasket. I believe the gasket is the thicker cobb gasket, but im not sure why it wouldnt be seated on both sides. It may be a defect in the uppipe or gasket. If my tightening doesn't work ill look at the OEM gasket or try loosening the brackets on the turbo to maybe move the uppipe closer to where it needs to be.

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Also a kind of unrelated question but is one if the motor mounts near the header? I found some kind of support looking thing pretty deteriorated.

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