David L

I have a My96 WRX July (260). It is only producing 0.6 bar boost. I think it should produce around 0.9bar. I changed the pressue sensor. No change to the boost. I then replaced the wastegate solenoid. It then started to produce too much boost 1.5bar. After a mile or so it then returned to 0.6 bar.
Is 0.6 bar controlled by the ECU. A safe mode if the engine has a fault or is producing too much boost.
No check engine light has ever come on.
Any ideas would be appreciated

David

Dave Mitchell

David,
I have a MY93 WRX. I have had it since May, I have never gone over .75bar untill the the last few days where I`ve seen it goto .9bar in third on a nice cold nite.
I thought it should be higher as well.
Does anybody know ?

Dave

GavinP

David and Dave ....

Normal boost for a 94-96 car is around 12-14 psi (0.8 - 0.95 bar).

The ECU should cut out at 15.5psi - stops the fuelling as a safety feature.

The ECU does have a "limp home" mode which may explain the pressure loss. As Dave said, temperature also affects the boost level.

Take a look at

David L

Gavin,
Thanks for the boost settings. So my car is definitely running low boost. I wonder is 0.6bar boost the "limp home" mode settings. My car is showing no error codes and even when I reset the ECU nothing changes. The only thing that has made any difference is changing the solenoid (but that lasted only for a mile or so).
Also my ecu never cut out at 15.5 psi it let it boost to 1.5 bar. Any ideas would be appreciated.

David

MatthewR

David,

What RON fuel are you using? That might have something to do with it.

Have you always had 0.6bar or has it dropped to that from a previously higher level? And when the boost went up to 1.5, was the performance noticably different? If not, then it could be simply a fault boost gauge (bit of a long shot).

From what you've described though, I would suggest it's a faulty ECU. Select/detect or a rolling road diagnostic session might be your best bet. Or post in the General Questions... more people tend to read that board and you might find some more ideas from there.

Around 0.9bar is what you should be getting definitely... I also have a MY96 WRX and that's what I get with not much variance from climate changes.

Good luck in fixing it...


Matthew

Bob Rawle

Sounds as though either the solenoid is incorrectly connected (piped) or is not working (may be an ecu issue). 0.6 bar is exactly the boost that is achieved when either of the above scenarious exists and is the limiting pressure of the actuator.

The port at the top of the valve should be connected to the outlet of the turbo, the pipe should be about 3 mm dia changing to 4 mm via an adaptor under the turbo feed air pipe.

The actuator should be connected to the middle port of the solenoid by 4 mm bore pipe.

The bottom port should be connected to the black resonator box (under the air pipe again)

Try this, ignition on but engine off, lift bonnet and move the throttle at the same time as carefully listen to the solenoid, it should start to click. If not, unplug it and test it with a 12 volt dc supply, it should click as you apply and remove voltage to it.

If the solenoid clicks (ignition on) then its most likely the pipework, if not then its most likely a wiring fault or an ecu problem. The solenoid is directly pulsed by the ecu. (assuming the solenoid is good)

My STi Version 2 is a MY96 with the same boost control components as yours.

Bob

GavinP

David,

[Amended after Bob posted - I will have to learn to type faster.... ]

I would suggest that at this point it is best to contact a specialist [if Bob's advice does not highlight the problem].

Whereabouts in the country are you ?

In the meantime, I would check all of the hoses to ensure that they are all OK. Another thing to think about is whether your boost gauge is reading correctly ?

Bear in mind also that the ECU error codes only show problems which working sensors can detect - this does not cover everything.

Be very careful when testing/driving (watch the boost gauge like a hawk) and ensure that your car does not produce more than 1.1 bar of boost. [If it goes beyond this, back off immediately. Bear in mind you are trusting the reading of the boost gauge - if it is faulty, you could seriously damage your engine].

[If Bob's advice doesn't highlight the problem - seek out a specialist who can inspect the car in person]

Thanks

Gavin

[This message has been edited by GavinP (edited 18-12-1999).]

David L

Thanks for all the replies. I will try some of the advice tomorrow. Since I have got the car it always runs max 0.6bar. I have always put in super Unleaded. I don't think it's a faulty boost gauge matthew as there was a noticably difference in performance.
I will follow Bob advice and see if the solenoid is working properly. I am in northern Ireland and would rather give it a go and try and fix it myself. I will be very careful when driving as i know over 1.1bar can do serious damage.

David

firefox

Where the heck did this post come from ?

I have come across Solenoids that have actually been bypassed.. and the actuator diretly connected to the manifold or turbo outlet...

As Bob has said.. if you are running about 0.6bar... this is the mechanical pressure at which the actuator opens. Therefore, either:

The solenoid is bypassed.
Solenoid is faulty
ECU is sending crap to the solenoid...

J.

David L

I have a look at the car today. Bob I checked the way the solenoid is piped and it is different to what you said. The Bottom port is connected to the black box resonator box.(this is ok) But the middle port is connected to a pipe between the turbo and intercooler. The top port (3mm into 4mm) is connected to what I assume is the actuator(sits on the driver side of the turbo).
Is this definitely piped wrong and if so I will swap over the pipes.

David

Bob Rawle

This is definately not correct and is the cause of your problem. The actuator must be connected to the middle port and the turbo outlet to the top port.

Let us know !!

Bob

David L

Bob,
I changed the pipes to the correct ports.....and.. It worked!! I now have 0.9bar boost. I can't believe that someone fitted the hoses wrong..
I very much appreciated all the advice. So Bob if you ever come to Ireland I owe you a pint of the good stuff....

Thanks a lot..

One happy ScoobyNet and SIDC member

David