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Discussion Starter #1
Short story:
2004 EJ205 Forester 2.0 Turbo will now hardly pull at all below 3500RPM, and I am struggling even to increase the RPM when flooring the throttle. I achieve increased RPM eventually by pumping the throttle. See this video:
In the beginning of the video I simply press the gas pedal to the floor, which under normal circumstances should wake up the beast immediately! However it just stays around 1500RPM while sputtering a bit, unless I pump the gas, in which case I can force it up to higher RPM, where it seems to run relatively fine. Problem is that it's hard to achieve higher RPMs while driving as I have no power on lower RPMs... It started out as a slight hesitation when accelerating from low RPM, and gradually got worse over 2 weeks and 1000km.
It takes a bit of cranking to start too, and runs a bit rough on idle, shaking a bit:
There's a ticking sound from the engine, especially when cold. I'm guessing valve adjustment is required, but I'm relatively new on Subi's as the other ones I've had just keeps running with no issues, so I haven't needed to do much until now.

Long story:
I bought a "new" Forester, a 2004 Turbo (EJ205) almost three weeks ago. On the 5hr drive home I almost ran out of gas as the light didn't come on until it was almost empty. It started hesitating on acceleration and running roughly, and the Check Engine Light came on, so I pulled into a gas station and filled it up, which seemed to fix the problem, except the CEL, which stayed on.
I suspected there may be condensation in the tank (we currently have temperatures around the freezing point), so after a few days, as I still could notice a slight hesitation on low RPM, I filled it up and added anti-condensation additive (yes, I know that all it does is bind the water molecules to the gasoline, but at least it won't try to run on pure water). However, this had no effect, but I had work to do and absolutely no time to play around so I continued using it.
Over the next two weeks and 1000km it gradually got worse. Here's a video a few days ago while accelerating (pedal to the metal as usual) on a relatively flat road:
As you can see here, there clearly is a problem, but it still works. After driving a couple of hundred km to get home, it got way worse, until the point it is today, where I almost didn't get up the hill to the house (with an almost empty fuel tank), and where it is almost impossible to get it about 1500RPM even in neutral/park:
(same video as the first one I referred to in the short version).

I eventually got home and checked the error code: P0171 - System too lean Bank 1

Another thing is that I filled the oil to the top level before I started using it, and about 1000km later I checked it again, and I couldn't see a single drop on the dipstick! I think I'm going to change to a ticker oil - is it OK to use mineral oil?

What I have done:
Asked the previous owner about the error code, as they left me an invoice from a garage, where this code is mentioned. She said they changed the fuel pump and filter, as the fuel pressure was a bit low (2.2 bar instead of 2.8-3.1 bar), as well as the fuel filter (it looks completely new, although they did have the engine washed a couple of months ago). So based on that:
  • New fuel pump
  • New fuel filter
  • Drained the fuel tank by attaching a hose from the fuel filter to a gas can and turning on the ignition multiple times until the fuel pump was not pumping anything but air, then added 20 liters of clean fuel to the tank. The fuel that came out did not look dirty and did not appear to have any water in it (although I'm not entirely sure if I would be able to detect that).
  • Checked air filter - squeaky clean, I suspect the previous owner changed this.
  • Cleaned the MAF sensor (it didn't seem that dirty, but I don't really know how it's supposed to look. Anyway, now it's clean as a whistle)
    526899
  • Removed one spark plug (#3), which was a NGK PFR6G and had some carbon deposits, which according to ancient wisdom means a too rich A/F mixture - the opposite of what the error code indicated (I did touch the tip of the electrode just to see if it would wipe off):
526898

Given that the car runs extremely well once I get it above 3500 RPM, I kind of doubt it's the plugs, but what do I know?

Is it possible that a faulty sensor (MAF/O2/lambda/...) alone can cause the symptoms I'm experiencing, or must there be something more serious wrong here?
I have a 2000 model that works fine apart from worn out brakes that I need to change. I can borrow parts from that one. Which sensor or other part do you think I should try swapping first?
Are there anything else I can do to diagnose this issue?
 

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2009 Legacy
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The loss of nearly all measurable oil is concerning. Does it drop oil?

I'd make sure that engine is breathing well: check the air intake and make sure some animal didn't make a nest in there.
Maybe a blocked exhaust.
 

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Discussion Starter #3
The loss of nearly all measurable oil is concerning. Does it drop oil?

I'd make sure that engine is breathing well: check the air intake and make sure some animal didn't make a nest in there.
Maybe a blocked exhaust.
Thanks for your reply,

It does not seem to drip any oil, but I will check this more thoroughly. Nor does it seem to burn much of it, as the smoke from the tail pipe is negligible, and white when there any (cold start).
I did read somewhere that up to 1L oil per 1000km is considered normal for these engines. Seems a bit excessive to me, but...

I tried to feel around the air intake, and it seems completely fine. The car has been in regular use by the previous owner, and continuous use by me, but I'll unscrew all the ducts and check them thoroughly tomorrow morning.

Blocked exhaust? Hmm, didn't think of that! Makes sense, almost like the engine brake on big (old) trucks, also used to stop the engine. How can it become blocked though? I mean what could clog it? Oil maybe... I might try to remove the exhaust pipes so it will have free unrestricted flow, but I suspect it with spew error codes if I do so...
 

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Discussion Starter #4
Just thought of another thing. Could the timing belt have jumped? Would this explain the symptoms I've getting? If so is there a good way to determine this without disassembling half the engine?
 

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Just thought of another thing. Could the timing belt have jumped? Would this explain the symptoms I've getting? If so is there a good way to determine this without disassembling half the engine?
Yeah, that could have happened. I don't think there's any other way but to pull the timing covers off

Regarding oil consumption, one quart every 600 miles seems a bit much to me. You don't want to run that engine low on oil.
 

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Being that this is a turbo engine,I believe the turbo is your problem.Disconnect the up pipe from the intake manifold and I will bet that it's coated with oil.You're losing oil through a bad seal in the turbo and it's that oil that you see on the plugs.With a bad oil seal,the bearings in the turbo aren't being properly lubricated.The lack of lubrication has made the bearings sticky so the shaft doesn't spin freely as it should.That's why you have no power until you get the revs up.You need higher revs to overcome the excess friction to get the turbo to spin up.that would have the effect of a plugged exhaust that you describe.Being that the car is 15 years old,it's likely well over due for a fresh turbo.That's likely why the previous owner decided to sell it.

Also,don't touch the timing belt.If it had jumped a tooth then it wouldn't have any power to speak of at any RPM.That's if it ran at all.It also wouldn't account for the oil loss.That's unless it caused other serious damage such as crashed a piston into a valve and it runs too good for that to have happened.
 

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Discussion Starter #7 (Edited)
Being that this is a turbo engine,I believe the turbo is your problem.Disconnect the up pipe from the intake manifold and I will bet that it's coated with oil.You're losing oil through a bad seal in the turbo and it's that oil that you see on the plugs.With a bad oil seal,the bearings in the turbo aren't being properly lubricated.The lack of lubrication has made the bearings sticky so the shaft doesn't spin freely as it should.That's why you have no power until you get the revs up.You need higher revs to overcome the excess friction to get the turbo to spin up.that would have the effect of a plugged exhaust that you describe.Being that the car is 15 years old,it's likely well over due for a fresh turbo.That's likely why the previous owner decided to sell it.

Also,don't touch the timing belt.If it had jumped a tooth then it wouldn't have any power to speak of at any RPM.That's if it ran at all.It also wouldn't account for the oil loss.That's unless it caused other serious damage such as crashed a piston into a valve and it runs too good for that to have happened.
Wow, that is the most insightful post I've seen in ages! It makes a lot of sense! It does explain all the symptoms. When I think of it, it did have a bit of a whine on higher RPMs, which could be from a turbo bearing as you describe. Just to verify, where do I find this up pipe? Are you referring to the exhaust pip that goes up to the turbo (the one that makes it spin)?
Wonder where I can find a decent turbo here in Norway...
Does anybody know what turbo this engine uses? And could I use any turbo meant for the EJ205, such as one from the STI?
 

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Most are covering the right areas, I would look in this order, plugged cat converter or exhaust.
Plugged up pipe
Turbo failure-- however, the symptoms are not typical of a turbo failure


The clue is the code, is this the cause or the effect? Have you looked for air intake leaks or replacing b1s1

Sent from my SM-N975U1 using Tapatalk
 

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This does scream of timing jump. It isn't about the minor change in valving, its about the sensing error for ignition timing. Definitely pull the timing covers to check it. Not a hard job.

The engine will rev to redline without a turbo. It's not that. If the turbo bearings were "sticky" it would immediately self destruct due to heat generation. That tubine can spin 20k RPM, even a tiny amount of friction would generate a ton of heat and cause meltdown.
 

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This does scream of timing jump. It isn't about the minor change in valving, its about the sensing error for ignition timing. Definitely pull the timing covers to check it. Not a hard job.

The engine will rev to redline without a turbo. It's not that. If the turbo bearings were "sticky" it would immediately self destruct due to heat generation. That tubine can spin 20k RPM, even a tiny amount of friction would generate a ton of heat and cause meltdown.
No way it can be that it jumped timing.As I said earlier,an engine that has jumped time will not run "extremely well" ,as the OP stated,at any RPM.It also will not account for the loss of oil.

If the bearings in the turbo are sticky it will not "imediately" self destruct.If completely starved of oil it will seize "imediately".It's getting oil but not quite enough due to a bad seal which is the cause of the oil loss.It's that oil that turned the plug black even though the ECU said that it's running lean which would turn the plug white.It's not necessarily sticky due to lack of oil.It's also very old,the bearings will be worn and it will not spin as free as it once did.It's in the early stage of complete failure,the pervious owner knew it and that's why he sold it.He didn't want to fork out the money for a new turbo.

How an engine will rev without the turbo means nothing.If he were to remove the turbo and it DID rev right up to redline then that would mean that the turbo was restricting the flow of air in and out of the engine and thus the turbo is the problem.It doesn't want to rev at all with the turbo on it because the turbo doesn't want to spin up which results in excessive back pressure in the exhaust just as a plugged cat would do.A plugged cat or any other part of the exhaust will not suddenly allow the exhaust to flow freely above a certain RPM.If it won't allow a small amount of gas to pass then it CAN'T allow a large amount to pass either.A turbo that doesn't spin free as it should will break loose at a certain RPM because that is when there will be sufficient exhaust pressure to overcome the increased friction in the worn turbo.When the turbo DOES break loose and spins up,it will then allow the increased exhaust gases to escape thus allowing the engine to breath again and it then runs as it should.
 

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Wow, that is the most insightful post I've seen in ages! It makes a lot of sense! It does explain all the symptoms. When I think of it, it did have a bit of a whine on higher RPMs, which could be from a turbo bearing as you describe. Just to verify, where do I find this up pipe? Are you referring to the exhaust pip that goes up to the turbo (the one that makes it spin)?
Wonder where I can find a decent turbo here in Norway...
Does anybody know what turbo this engine uses? And could I use any turbo meant for the EJ205, such as one from the STI?
The pipe is the big one that connects to the back of intake manifold.Disconnect that pipe from the back of the intake and you will find that it's coated with oil.

Since the turbo needs replaced anyway,now would be a good time to to upgrade it with one from the STi.I'm no expert on what will and will not work but it should bolt right in.It's possible that you might have to change one or two pieces of pipe to accommodate the increased capacity of the bigger turbo.Again,I'm no expert,but the ECU might not be able to cope with a larger capacity turbo and might need some tuning to get the two to play nice together.Of course,the easiest,cheapest and safest thing to do is replace it with one exactly like the one you have.
 

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Engines are less sensitive to ignition timing as RPM increases. Very easy to have it stumble at low RPM with a timing or valving issue but run great at high RPM. Ask anyone with a big cam or a blower or a slipped timing belt. These engines are even KNOWN for slipping belts because the external hydraulic tensioners are junk and people love to rev them.

Listen to the starting video. Tell me that doesn't sound like bad timing.

Its a turbo engine. It runs rich. Plugs are only an indicator, not a rule.

Oil in the intake is PCV, like every other old engine of course you will find oil in the intake.

You are full of a ton of conjecture.
 

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Engines are less sensitive to ignition timing as RPM increases. Very easy to have it stumble at low RPM with a timing or valving issue but run great at high RPM. Ask anyone with a big cam or a blower or a slipped timing belt. These engines are even KNOWN for slipping belts because the external hydraulic tensioners are junk and people love to rev them.

Listen to the starting video. Tell me that doesn't sound like bad timing.

Its a turbo engine. It runs rich. Plugs are only an indicator, not a rule.

Oil in the intake is PCV, like every other old engine of course you will find oil in the intake.

You are full of a ton of conjecture.
Having a blower or not has nothing to do with timing.It's just a turbo driven by a belt.If that belt jumps nothing will change.A blower will actually run better at low RPMs than a turbo due to the absence of turbo lag.A big cam will always run rough at idle due to the profile of the cam lobes,even when it's timed perfect and will smooth out as RPMs rise.Jump a tooth on the timing and it will run like crap at all times.

The timing belt has nothing to do with ignition timing.The ignition is timed off the crank trigger/sensor.The timing belt is responsible for valve timing.All engines are extremely sensitive to that and will not run well at any RPM because the valves will not open and close at the right time so it will always be low on compression no matter the RPM.I've seen many engines that have jumped time and they run like crap if they run at all no matter what the RPM.Not to mention that this is an interference engine.If the valve timing isn't right then the pistons will crash into the valves and the engine will be destroyed.That's what happened to my aunts '05 Impreza.

Yes,it is a turbo engine.However,it's also fuel injected so it will only run rich if there's something wrong.When all is working as it should it will have the perfect fuel to air ratio.That's why they don't use carburetors anymore.They are seldom if ever set to supply the right fuel ratio.Fuel injection can change the mix on the fly to insure the mix is correct and a carburetor requires constant adjustment to cope with changes in temperature and altitude.Turbo or no turbo,it's still an internal combustion engine,it must follow the same rules of physics and thus requires the same fuel to air ratio to run right.

Since the PVC valve is low on the intake manifold the oil will only be found from the PCV valve down to the valves.This engine will have oil in the tube leading to the intake where oil from the PCV cannot reach because it's being drawn down into the engine and not being pushed up and out of the intake.Remember that this engine has a turbo charger so air is always being forced downstream which will carry oil from the PCV down and into the cylinders.I would also bet that the inter cooler is also full of oil.Tell me how oil from the PCV is going to get in there.Oil like water runs down hill.
 

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That's a lot of words. Most of those thoughts are at least a little wrong. Not going to write an essay but:

1. Valve lift and timing is a continuum that affects volumetric efficiency and if not accounted for, ignition timing. Cam profiles and mechanical timing affect valve timing. If you mess them up well enough it wouldn't be hard to reduce power to the point it can't overcome friction at some low RPM, but can at some higher RPM, which is why he can break through the false ceiling.
2. You can't properly time an engine only off of the crank. You need a cam position sensor, otherwise what is the difference between TDC compression and TDC exhaust? That is why you need a cam sensor. You can get away with it using batch fire and wasted spark, but it's not a good system because injection angle is important.
3. FI engines aren't smart, they have base tables and respond to inputs within bounds. The AFR is literally never perfect.
4. PCV system has a breather upstream of the turbo. Some oil in the I/C is normal.

Could have pulled off the left and right timing covers and just checked in the time he took to type all that gook. Remove the belts and the A/C tensioner mechanism with a 12mm. Need a 10mm on a 1/4" drive ratchet to remove the covers. You can remove the rad fan/shround if you need to for access, no need to drain any coolant. I believe the crank bolt is a 27mm. Cam bolt is a 14mm, but I prefer to spin the motor over on the crank - less chance of slipping the belt.

Or blindly go buy and install a turbo.
 

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That's a lot of words. Most of those thoughts are at least a little wrong. Not going to write an essay but:

1. Valve lift and timing is a continuum that affects volumetric efficiency and if not accounted for, ignition timing. Cam profiles and mechanical timing affect valve timing. If you mess them up well enough it wouldn't be hard to reduce power to the point it can't overcome friction at some low RPM, but can at some higher RPM, which is why he can break through the false ceiling.
2. You can't properly time an engine only off of the crank. You need a cam position sensor, otherwise what is the difference between TDC compression and TDC exhaust? That is why you need a cam sensor. You can get away with it using batch fire and wasted spark, but it's not a good system because injection angle is important.
3. FI engines aren't smart, they have base tables and respond to inputs within bounds. The AFR is literally never perfect.
4. PCV system has a breather upstream of the turbo. Some oil in the I/C is normal.

Could have pulled off the left and right timing covers and just checked in the time he took to type all that gook. Remove the belts and the A/C tensioner mechanism with a 12mm. Need a 10mm on a 1/4" drive ratchet to remove the covers. You can remove the rad fan/shround if you need to for access, no need to drain any coolant. I believe the crank bolt is a 27mm. Cam bolt is a 14mm, but I prefer to spin the motor over on the crank - less chance of slipping the belt.

Or blindly go buy and install a turbo.
1. Yes,Valve lift and timing is a continuum that affects volumetric efficiency.And if that timing is off then efficiency is lost and thus power is lost.Changing/increasing the RPM will not magically put it back in time to restore that efficiency.Once again,if the valve timing is off,even if by just 1 tooth,It will run like crap,if at all,at any and all RPMs.It's impossible for any engine to run "excelent" at any time at any RPM if valve timing is off because it will be low on compression.It is especially impossible for any interference engine to run if the cam timing is off because the engine will be destroyed when the piston crashes into the valve.

2. Ok,yes,the cam sensor ONLY tells the ECU if it's on a compression cycle or exhaust cycle.That doesn't tell it when to fire the plug.It's the crank trigger that controls exactly when to fire the plug.So again,the timing belt and thus the cam sensor have nothing to do with ignition timing.That's the job of the crank trigger.It's called a trigger and not a sensor because that's what "triggers" the ignition to fire.The cam sensor will tell it which cyilnder to fire and not when to fire it.

3. FI engines are indeed smart.They don't just operate just off of base tables.Those base tables are used for when the ECU has been reset and it's memory erased.Those base tables are just a starting point.As you drive it takes readings from the sensors,makes adjustments on the fly to make the engine run as good as possible and those adjustments are stored in the cars memory.That's why after a reset of the ECU,when you first start it,it may not fire right away and when it does fire,it will run rough for a moment until it has had a chance to fine tune everything.If it just ran only off of base tables then there would be no need for temperature and oxygen sensors.It's those sensors that allow the ECU to make the proper adjustments to insure the mix is perfect for the conditions it's operating in at that time.

4. Sorry charlie,the PCV is downstream from the turbo and the inter cooler in the intake manifold.It would be stupid to put the PCV upstream from the turbo.The turbo has very tight tolerances for balance and clearance between the blades and the housing.Running all that crud form the PCV would cause deposits on the blades which will gum it up and likely throw it out of balance.It must be kept absolutely clean.That's why they put the PCV in the intake,like all other cars.

Check the cam timing if you wish.I can tell you right now that it's a waste of time.One more time,an interference engine will destroy itself if the cams are not timed correctly.Why don't you move the timing belt one tooth on your car and start it up for us and tell us what happened?Better yet,get it on video so we can hear the sound of an engine destroying itself.
 

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You're still just a little bit wrong on every point, and not worth reasoning with. I've got my real suggestion in though, so good luck lupisak, let us know if you tagged along for this ride and what new information you have.

I realized last night you don't actually have to remove the AC tensioner bracket and the middle cover, you can probably just remove the two outer covers and try to align all 4 cams. If you can't, then you know the problem. Unlikely they all slipped the same amount. Probably the left head intake cam is the culprit - nearest the tensioner and houses the cam sensor.
 

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@lupisak - I would be be cautious with the advice from Mario. Ryan is correct. While the turbo may indeed by bad and blowing oil into the intake, it is not the cause of your idle/low RPM power problem. A plugged exhaust is also not your problem as that gets worse as RPM increases, not better. To answer your question on what causes a blocked exhaust; the most common cause is breakup of the catalyst honeycomb in the Catalytic Converter.

You should take Ryan's advice and check the timing belt. Mario is correct that a failed timing belt will cause serious damage with valve/piston collision. However, if timing is off by only one tooth and sometimes more than one, then, depending on the engine, the cam timing error may not result in physical interference and the engine will run poorly, but without damage.

Your P0171 lean code and the carbon on plug #3 is a tip-off. A vacuum leak will cause the lean condition and the computer will make the mixture rich to compensate. If the leak mainly impacts cylinder #1, then cylinder #3 will run rich. You really to see what your long and short term fuel trims are - this requires a scan tool.
 

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Discussion Starter #18
Most are covering the right areas, I would look in this order, plugged cat converter or exhaust.
Plugged up pipe
Turbo failure-- however, the symptoms are not typical of a turbo failure


The clue is the code, is this the cause or the effect? Have you looked for air intake leaks or replacing b1s1

Sent from my SM-N975U1 using Tapatalk
That's true, maybe I should hold my horses looking for a new turbo until I am 100% sure. It could be a different reason for the effect of a plugged exhaust effect. Maybe I could remove the exhaust pipe and see how it runs without.
What are the typical symptoms of a turbo failure?

Yes, I've looked for intake leaks (or listened for them), I can't seem to find any, but I don't know a way to search for leaks other than listen for a sucking sound. Is there a better way?

Regarding Bank1 Sensor1, yes, I can pull that off the 2000 model I have that is awaiting repairs to test, but is it possible that a sensor failure alone would cause this big issue, and gradually developing from a slight hesitation to almost complete lack of power below 3500RPM?
Do you happen to know the typical symptoms of an S1B1 failure?
 

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Discussion Starter #19
This does scream of timing jump. It isn't about the minor change in valving, its about the sensing error for ignition timing. Definitely pull the timing covers to check it. Not a hard job.

The engine will rev to redline without a turbo. It's not that. If the turbo bearings were "sticky" it would immediately self destruct due to heat generation. That tubine can spin 20k RPM, even a tiny amount of friction would generate a ton of heat and cause meltdown.
Good point!
And I don't feel any excessive heat there. It feels completely normal.
 

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Discussion Starter #20
No way it can be that it jumped timing.As I said earlier,an engine that has jumped time will not run "extremely well" ,as the OP stated,at any RPM.It also will not account for the loss of oil.

If the bearings in the turbo are sticky it will not "imediately" self destruct.If completely starved of oil it will seize "imediately".It's getting oil but not quite enough due to a bad seal which is the cause of the oil loss.It's that oil that turned the plug black even though the ECU said that it's running lean which would turn the plug white.It's not necessarily sticky due to lack of oil.It's also very old,the bearings will be worn and it will not spin as free as it once did.It's in the early stage of complete failure,the pervious owner knew it and that's why he sold it.He didn't want to fork out the money for a new turbo.

How an engine will rev without the turbo means nothing.If he were to remove the turbo and it DID rev right up to redline then that would mean that the turbo was restricting the flow of air in and out of the engine and thus the turbo is the problem.It doesn't want to rev at all with the turbo on it because the turbo doesn't want to spin up which results in excessive back pressure in the exhaust just as a plugged cat would do.A plugged cat or any other part of the exhaust will not suddenly allow the exhaust to flow freely above a certain RPM.If it won't allow a small amount of gas to pass then it CAN'T allow a large amount to pass either.A turbo that doesn't spin free as it should will break loose at a certain RPM because that is when there will be sufficient exhaust pressure to overcome the increased friction in the worn turbo.When the turbo DOES break loose and spins up,it will then allow the increased exhaust gases to escape thus allowing the engine to breath again and it then runs as it should.
Thank you again, it looks like a good way to test to be sure it's the turbo, simply removing it and see the effect. Hopefully it's "simply" removing it, I don't know how stuck a turbo that has sat there for 350000 km will be...
And it's true, a plugged exhaust would never allow even more air to pass, it would simply lack power any any RPM. I've had many broken cars, but never one with these symptoms.
As far as my logic goes, I would be surprised if it's not the turbo, but I keep my mind open.
 
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