Turbo bar gauge does not go beyond zero bar

[Thomas_hmlo]

With the previous exercise of sorting out the engine problem, my car was running fine until today.
Well.... Until yesterday.
Tried searching for similar topic thru google without success.

The problem with the car is now when driving, there is no turbo boost.
The turbo bar gauge does not go beyond 0 bar.

Spent a lot of time yesterday checking the tubes and replaced the followings;
A. Fuel filter at the engine firewall.
B. The rubber tube which connects to the boost modulator because the tube has a split.
C. Replaced the fuel regulator and the tubes which connect to the fuel regulator.
D. Replaced the tubes which connect to the carbs. They are tight and no air leak.
E. Replaced the small rubber tubes which are located nearby the master brake cylinder.
F. Blanking off the tube which connects to the anti run on valve.

But the car turbo gauge is still not go beyond 0 bar.

Last time after repairing I heard some leaking sound when the car is under boost.... But it seems the turbo was kicking in. Then I did not drive it for one week.

Please kindly help!!

[an old original]

Does the gauge still show a vacuum when on over-run/tick over?

[Thomas_hmlo]

The gauge only goes max to zero bar. It does not goes beyond that point.
The turbo does not boost when I drive the car on road at high rpm.

[prop]

If you disconnect the pipe to boost modulator what happens.
If this was split and you replaced it and now there is no boost perhaps this is where to look?
It will have been leaking off and your waste gate will have stayed shut longer giving higher boost.
If now it isn't leaking off and you are getting no boost it could be ECU or modulator valve (connections or operation)
Although it stopped boosting before you replaced the pipe

[G96LUE]

The ecu & boost modulator wont stop the turbo boosting.

I believe the ecu only monitors the boost pressure/revs and opens the modulator valve (over 3k revs i think) to keep the wastgate closed a little longer which then increases the boost pressure from 4.5psi to 7.5psi (i think).

If the modulator is blocked off and the ecu disconnected you will still get boost but the waste gate will open at 4.5psi so will still be driveable.

If you have no boost pressure at all i'm not sure what the problem is.

If all the pipes are connected correctly and have no splits i can only think of the following:-

it could be your wastegate is stuck open or the actuator arm has become detached from the wastegate pivot. The pressure from the inlet side will then just be sent straight into the exhaust.

Worst case scenario is the turbo is either seized or has a foreign object jamming it so the exhaust gas isn't rotating the compressor on the inlet side.
You can check this by removing both jubilee clips on the orange silicone hose between the turbo & Plenum. i think you can then slide the hose enough to let air leak out.
If you then start the car and rev the engine with your head under the bonnet you should hear or feel air being forced out of the joint.

i dont suppose this is much help but you never know.

[Thomas_hmlo]

Did more checking today! Hope it will not be too boring.

A. Check the Plenum chamber by replacing with another one. Check the pressure of both before installing.... By holding compress air gun. They both hold the same pressure value. The screws which mount the chamber to the fiber tray were so difficult to align. Luckily with patient... They went back to the original location.

B. Replace the tee shape joint. Mine was plastic and change to metal material. Well.... That is only to prevent future breaking. One of the tubes has a split and I replaced it.

C. Check the fuel pump by taking it off. Only has a very small bit of rust accumulated at the pump mesh. Anyhow, sine the one I used is has different nosle size, I replaced it with the one I got from MS.

D. Checked air filter tubing no damage. Also replace the air filter with K&N which fits the original air box. Plugged the fresh air vent since I do not use it. Plus too many dust accumulated along the tube and the sponge inside the tube. Removing the air filter is never an easy job as the metal clips at the top touch the body panel. Anyhow, untight the screws which hold
the air filter housing. The fitting can be completed

E. Check engine oil level, check and replace the spark plug per user manual....

F. Replace the ECU with Metro turbo ECU. The tube connects to
Plastic connector was dripping oil. Replace the tube and plug
in my second ECU.

G. Also check the boost gauge tube. The tube is with oil in. Clean the tube and put it back.

H. Took away the big rubber tube connect to the plenum chamber.
flow. Not too high flow.

After all these checking. Some
Improvement but no time
To check further due to
Time limitation.

[Thomas_hmlo]

Would like to know the max bar gauge reading when it is on road.

[Thomas_hmlo]

Sharing some photos.

Air filter box.


Air filter.


Some cracks lines found!! Common problem of classic Mini.


Fresh air duct next to the air filter pipe.


Took away the dash panel


ECU


Pipe to ECU wet mark are fuel.


ERA vs Metro Turbo ECU

[prop]

Have a look at this thread.
http://www.turbominis.co.uk/forums/inde ... tid=467326

If your actuator is weak or has not enough pre-load then may be this could be part of the problem. They can get weak with use because of the heat down there. If you have had leaking split pipes it would act as extra bleed off so allowing the actuator to stay closed longer in the past. Replacing them would stop the bleed off therefore opening the waste gate sooner. A common way used by some to increase the boost on an engine is to increase the pre-load on the actuator.
The actuator is in such an access restricted area it is difficult to get too and work on.
Be careful if you increase the boost you don't want to destroy your engine. There is much more to raising the boost than just keeping the waste gate closed longer.
Those cracks look bad.

[Thomas_hmlo]

Thanks for the reply.
I think the problem is the cylinder gasket failure at the inlet and exhaust manifold.

The bolts are very loose.
Will check more later.

May I know the turbo bar pressure when you are driving?
Some ppl said up to 4K rpm is at 0.28 bar. Above 4k rpm max 0.48 bar.
Is this correct? Mine only max 0.2 bar now. I can hear leaking sound when driving.