Thread: Boost sensor

Yes it will record faults.

No, its not a good thing to do to your motor.

Its running a default boost value now, performance will be off, economy will change.

u diens agent is 'n dwaas

Can't comment on consumtion but the performance is up a bit, especially low down.
Is this not a indication that the sensor was at faul from the beginning?

Recently I found that the small pipe feeding the sensor came off after I fiddled in that earea.
Performance was notacible down at low revs.
After it was put back on, power increased and low revs performance was excelent. So much that I could drive at 1250rpm in 5th and just drive off.
After a short while performance was down again but but not low as before.
Any other place too look at?
There's no visible leaks anywhere and MAF seems fine.
Will also try a new sensor to get the engine back to normal again.

What should the Turbo actuator rod length be ad measured between what?

Sal weer probeer. (Will try again)

Rudolph, think you may be talking about the boost modulator. The boost sensor is on the intake manifold.
The boost modulator has 3 hoses to it and controls the wastegate actuator via a signal from the ECU.
Don't disconnect it, replace it or you will get overboost issues and ECU will cut fuelling causing it to surge.
The modulator is on the LH side just under the turbo intake with one hose to the modulator, one to the turbo outlet and one to the turbo intake hose.

Cheers

Andrew


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Originally Posted by LOVEMYRANGIE

Rudolph, think you may be talking about the boost modulator. The boost sensor is on the intake manifold.
The boost modulator has 3 hoses to it and controls the wastegate actuator via a signal from the ECU.
Don't disconnect it, replace it or you will get overboost issues and ECU will cut fuelling causing it to surge.
The modulator is on the LH side just under the turbo intake with one hose to the modulator, one to the turbo outlet and one to the turbo intake hose.

Cheers

Andrew


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I knew that!!!
Sorry for the confusion.
It's the modulator that was removed.
From where the power loss then?

Should this modulator be normally open or closed with no power on it?
Mine lets air through on every pipe by blowing and sucking except the high pressure side(Turbo).
This one shuts when negative pressure is applied.
The engine is loosing power somewhere.
But where.
At the moment it drives so nice I'm reluctant to replace the modulator.

oops!

From what I can work out, the modulator should bypass pressure back to the intake when not activated. When boost is sensed too high by the ECU, it activates the solenoid to switch boost to the wastegate valve bypassing exhaust pressure around the turbine and limiting turbo speed.
When the boost drops to safe level, it switches back venting pressure from the wastegate back to the turbo intake pipe. This generally makes it a normally open 3 way solenoid as unenergised it's not controlling anything.

If you are losing power, it's most likely the solenoid is stuck half way and pressure is being fed to the modulator constantly and possibly causing it to actuate prematurely.
I had the hose from the turbo outlet to the modulator pop off once causing the boost to go wildly high causing the ECU to cut fuel and start surging.
Cheers

Andrew

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When I blow into the turbo side of the modulator air exits into both the wastegate side and the turbo inlet side.
Seems the valve is busted. Thus the loss of power at high revs and just above idling.

The modulator is there to allow more boost under certain circumstances than what the wastegate actuator would normally allow. With the electrical plug disconnected there should only be a path between the turbo outlet and the actuator, not the turbo inlet, which prevents extra boost. The turbo inlet is used to bleed-off some of the outlet pressure to reduce the pressure going to the actuator which prevents the actuator from opening the wastegate either totally or so far and thereby increasing boost.

If there is a 3-way path without power applied then its stuck and needs replacing.