Not boosting past +0.45 BAR

Hi there people, I have a 2001 WRX Bugeye Impreza

As the title states im only able to boost as far as +0.45 bar, the car wants to keep pulling but their has to be something restricting the boost, For example in 3rd gear going about 2000 rpm and if i put my foot down the revs will get held up at 3000 rpm and will build up very slowly until 4500-5000 rpm and then she properly pulls the way it should be. Also when i do reach 4500-5000 rpm she will boost higher as far as +0.5/6 bar but i cannot safely test this well due to bad roads in my area.

I was told the problem could be the boost senoiled or the BOV sticking and letting pressure out.
I can take a video in a bit and share the link to it so you can see for yourselves.

If anyone has any information on how to solve this problem please let me know ASAP.
Thank you

Restrictor pill removed. Would limit to actuator 0.5bar pressure

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Easy checks to do

1. It's not the actuator. 99% of the time the car will over boost if its broken. If it is the boost controller then simple. Remove the vac pipe from the actuator and then drive the car. Without the pipe connected the car should boost, and boost fast so be careful because it could see 1.7bar

2. If no luck then remove the actuator arm from the wastegate arm. See if the wastegate arm moves. However the arm should only move about 40 degree angle at the most away from turbo towards exhaust/intercooler. Second thing is the arm when pushed towards turbo should line up with the turbo, be parallel. If when you move the arm towards the turbo and it moves pass that parallel mark then the wastegate "door" has broken off. (Seen this once but seriously doubt that's the case)

3. Otherwise check the boost pipe and intercooler for leaks. Also the hose clamps under the intercooler. Guys tend to over tighten hose clamps and the clamp cuts into the rubber hose. That cut turns quickly into a big tear from boost pressure and heat.

4. BOV maybe. Check the vac pipe to the BOV. Suck on the pipe and then hold your tongue over the hole for two seconds. When you then remove your tongue there should still be a slight vacuum. If there is then Im sure its fine.

Cheers lads,
I'll have a good luck in the afternoon with my mechanic and hopefully solve this problem. Also for paragraph 1, dose this mean I'll need to get a manual/electric boost controller?

Also I noticed this plug was taped off and I can't find whare it's meant to be, any ideas?
Thanks ????

For point 1. Just first check if the car boost faster than what it was. but like I said have a light foot on the accelerator as the car will over boost. All you doing is seeing is the boost coming sooner and faster.

Looking at that pic, you need to unbolt that red plate. That corner area has the controller there. Is this car still oem ecu?

Also take a pic of the turbo vac lines. I cant see more than two vac lines coming out of that red plate thing. Looks like no controller there. But take that plate off and take a pic.

Have you just bought this car. I reckon that the car had a man boost controller and when sold the owner take the man controller off and just connected the vac lines together, straight from actuator 2 turbo

I actually have no idea as I only have the car this past month, so I say it's the Standard ecu.
Here are some photos of it I took today, hopefully it's an easy fix ????


Hopefully these are clear for you Steve. Thanks

Right so lads.
Myself and my mechanic followed the list word by word while aswell checking the BOV and intercooler piping for leaks and everything came back positive that everything is holding pressure.
We then came to the conclusion that the problem is the boost solinoid, I then met with a Subaru breaker in Enniskillen and swapped the solinoid for a new one and still nothing changes as it's still reading 0.45 bar. Now we did remove the pipes from the actuator and yes she will reach 1bar but I did not go any further to save my engine.
Now we did find that the plug with the yellow tape around it had a pin in it which we have no idea why it's there but has to be for some reason.
Would a manual boost controller solve this problem or is it only a cheep fix to what could be wrong?


Please let me know what yous think as I really need this car to work properly for Dubshed at the weekend.
Thanks

That to me looks like a resistor for the up pipe I presume it's a wrx and someone probably fitted a decay up pipe at some stage

GORDON GT SERIES II said:

That to me looks like a resistor for the up pipe I presume it's a wrx and someone probably fitted a decay up pipe at some stage

Click to expand...

Would it really start to restrict the boost ?

They're generally fitted to sort out the check light when you decat the up pipe but shouldn't affect boost like that

Ok so there is no boost controller. Two it looks like the actuator is connected straight to the turbo.
i cant see properly with that pic. If you look at the turbo there is vac lines. can you get a wider shot of where those go. The black pipes.

scoobySteve said:

Ok so there is no boost controller. Two it looks like the actuator is connected straight to the turbo.
i cant see properly with that pic. If you look at the turbo there is vac lines. can you get a wider shot of where those go. The black pipes.

Click to expand...

Right so here is a picture, i outlined the pipes in red and green, the red outlined pipe from the actuator travels to the boost Solenoid and the green outlined pipe travels from the boost solenoid all the way towards the intake pipeing. The Pipe outlined in yellow travels from the T-joint to the turbo.
hope this helps lad

Hawkeye said:

Right so here is a picture, i outlined the pipes in red and green, the red outlined pipe from the actuator travels to the boost Solenoid and the green outlined pipe travels from the boost solenoid all the way towards the intake pipeing. The Pipe outlined in yellow travels from the T-joint to the turbo.
hope this helps lad
View attachment 103353

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Aww sorry it is there, didnt look properly. Ok so it all looks good there.Everything is in the right place. Ok second job check those plug lines for any insert, like a resistor in the pipe. Just squeeze the pipe you will feel. Ok what you should do not sure if you have done it. That Pipe going to the controller from the turbo, disconnect it to atmosphere. Go drive but be carefull. See how the turbo response. I want to see if the controller is stopping it boosting

scoobySteve said:

Aww sorry it is there, didnt look properly. Ok so it all looks good there.Everything is in the right place. Ok second job check those plug lines for any insert, like a resistor in the pipe. Just squeeze the pipe you will feel. Ok what you should do not sure if you have done it. That Pipe going to the controller from the turbo, disconnect it to atmosphere. Go drive but be carefull. See how the turbo response. I want to see if the controller is stopping it boosting

Click to expand...

Hi Steve, yes there is a little lump in the pipe leading for the turbo to the T-joint. I disconnected this pipe the the T-joint and the turbo will boost very well and fast!!!
Is the controller the insert in the pipe?

Is the lump before the T connector on the pipe coming from the compressor? The controller is under that red cover plate. Blue circle thing that the vac pipes run to.

scoobySteve said:

Is the lump before the T connector on the pipe coming from the compressor? The controller is under that red cover plate. Blue circle thing that the vac pipes run to.

Click to expand...

Hi Steve. I'm not much of a mechanic unless you mean the compressor is the turbo?
I've highlighted the lump in the pipe here in this picture

leave it, its not the problem. Ok it starting to sound like the boost controller is broken, or the boost is turned down??

That blue circle device that the vac pipes run to (the controller), it sits under the red cover plate. Like you said it has pipe coming from turbo, and then one going to air intake. Unplug the pipe going to air intake. I want to see if that's blocked somehow.

scoobySteve said:

leave it, its not the problem. Ok it starting to sound like the boost controller is broken, or the boost is turned down??

That blue circle device that the vac pipes run to (the controller), it sits under the red cover plate. Like you said it has pipe coming from turbo, and then one going to air intake. Unplug the pipe going to air intake. I want to see if that's blocked somehow.

Click to expand...

Ok I will do that once I get off work, I'll be done around 12am tonight. what should I be looking for when I unplug the wire leading to the air intake when I drive the car?
Thanks

Hawkeye said:

Ok I will do that once I get off work, I'll be done around 12am tonight. what should I be looking for when I unplug the wire leading to the air intake when I drive the car?
Thanks

Click to expand...

It's a vacuum pipe you unplugging not a wire. The boost controller is a air bypass valve. What you want to do is see if the air coming into it can then get out back into the intake.

scoobySteve said:

It's a vacuum pipe you unplugging not a wire. The boost controller is a air bypass valve. What you want to do is see if the air coming into it can then get out back into the intake.

Click to expand...

So shall I take the pipe off, turn on the car and see if there is air coming out of the controller? Or go for a drive and see if the boost rises in pressure?
Sorry if I'm being awkward just I'm not that knowledgeable with mechanics ????