hi, forgive my sloppy post but really need help
i have a subaru impreza 1998 2000 awd 2.0 turbo
my main issues is with the car not building boost unless under constant pressure on the accelerator as soon as you let off the accelerator boost dumps.
i believe it might be piped up wrong by previous owner
here are some pics, sorry about the quality



any help appreciated

 

Maybe I'm misunderstanding, but turbos only boost when you have throttle input.
Can you go into more detail?

 

What the issue is, is the fact the car doesn't build most of the time even under acceleration, it will only build any on a motorway under 5 minutes constant accelerator pressure if you let off when you finally build it up it will dump out and require another 5 minutes constant, there is no boost with regular road driving.

I renewed vaccum pipes and restrictor pill, cleaned out solenoid and fitted new lambda sensor.

I'm pretty sure the pipes are all wrong on turbo setup but not sure how they should go

 

standard setup is like this:


It's important that the restrictor pill is in the right place (the yellow dot hose) otherwise you won't make 14psi (standard boost).

It might be a more mechanical problem though maybe a leak in the uppipe? You could try running a plain vac hose from the turbo compressor nipple to the turbo wastegate directly. Bypassing the BCS system will give you spring pressure (around 7psi) and should be made easily.

if your not even making spring pressure then it could be the wastegate itself is broken or a leak somewhere.

 

My pipes are not piped like that at all,
Mine is a 3 pipe wastegate solenoid,
Turbo nipple and wastegate nipple not connected
T connector connected to wastegate solenoid top with restrictor pill, wastsegate nipple and boost gauge in car

 

OK - with a 3port solenoid you have a bit more work:



just follow the diagram, the restrictor pill goes into the INTAKE line. The lines to the wastegate and compressor are just plain lines.

The boost gauge should be fed from the manifold somewhere not the turbo vac lines.

 

Perfect thank you, I will check all this and give an update in the morning

 

Just out of interest where should the two pipes go on the brown purge control solenoid

 

 

is yours like this:


in which case it looks like one straight into the manifold whihc is T'd off and one under the manifold over to the evap doofer.

 

ok i think i got the hoses sorted but 1 last dumb question where the hell do the pipes on this go



I know now what it is, where do the 2 pipes go?

 

i can't make out where that is, is that the map sensor? Zoom out and take another snap for us

 

It's the pressure exchange solenoid but I got a feeling even that's piped wrong 1 pipe goes to map and other to turbo outlet nipple

 

as far as I can tell the one that points up towards the bonnet goes to the pressure sensor, and the one that points towards the engine goes to the intake manifold somewhere.

There's a picture in this thread:
https://www.scoobynet.com/general-te...-manifold.html

 

Perfect, one final question 1 of the pipes has what I can only describe as a white inline thing, I really wouldn't want to put that in the wrong area, it's maybe an inch in diameter, looks like maybe a filter

 

is it the the restrictor pill for the 3port - should be on the line going to the intake pipe. This dampens the effect of the 3port making boost a bit more smooth for you.

Take a picture sure and post it

 

http://i1288.photobucket.com/albums/...ps86bfa8d3.jpg

 

mmm not sure mr it must be a classic thing

i hope this isn't how you have your boost gauge wired up tho?
http://s1288.photobucket.com/user/ct...6f0bd.jpg.html

Your reading from there won't be very good and the gauge itself will be affecting how the boost control solenoid works. T it off the dump valve vacuum line you'll get a closer match to what pressure the ECU is reading.

 

Yep, that's how it was, the whole lot was wrong

 

Just been for a drive everything seems ok, on my turbo gauge I don't tick over on zero, is this correct,dial points down to 60 but when driving it's goes up to show around 0.8

 

If car is standard and running standard boost then yes there or there abouts.

 

Perfection, I must say thanks to all for the help, gotta do a lot of miles over next few weeks, now all I gotta do is figure the little inline filter and start knitting her up, gotta get exhaust first, doesn't sound like a Scooby at the moment, it's just wrong

 

yeh that's right 0psi on the gauge is when the pressure inside the manifold is equal to the pressure outside the manifold. The engine is always sucking in new air to pump out the back so when sitting at idle and the turbo isn't assisting things you should see a vac/negative reading on the gauge.

When the turbo is spooled up and creating more air charge that's when you get into postive boost pressure and the fun begins. 0.8/0.9 somewhere in that region is fine for standard car - you'll only make full boost generally in higher gears so don't worry if there's a big difference between 2nd gear boost and 4th gear boost that's all normal.

 

Thanks, all running nice now, so time to make her look and sound pretty