D5 turbo noise after remap euro 4 185hp (stalling, surging?)

[kobom]

Listen here: https://www.youtube.com/watch?v=-fxfS8E5Z-E
It occurs during gas pedal lift-off when the boost is gaining it's pressure, around 1500-2000 rpm. When doing the liftoff in higher rpm range then there is no noise. It sounds like the excessive boost has no place to escape other than back to the turbocharger. That started after remap, which included dpf and egr removal. Map was done by professional company with 15 years experiance with hundreds if not thousands of customers over the years.

What I've found from another forum:

Carful getting the EGR mapped out. Make sure they know what they are doing if they do. On the 185, the egr valve is opened when you lift off the throttle to dump boost pressure into the exhaust. If they map it out completely, you could loose driving refinement and possibly stall the turbo. best solution is EGR mapped out but retain lift off part and then you will be very happy.

Right, after doing some more research, checking the live data parameters,etc there is one problem with blanking the Egr valve.
On most vehicles, egr valve has only one purpose and that is to recycle the exhaust fumes. Unfortunately on Toyota landcruiser, it also acts as a Turbo pressure release valve( dump valve). That means that when releasing the throttle after acceleration, the excess pressure from turbo that remains in the intake system is being dumped trough egr valve back into exhaust system. When the egr valve is disabled or blocked, the excess pressure has nowhere to go and its being forced back to the turbo compressor and its putting strain on the blades.

Is it true that the Euro 4 D5 uses EGR as a sort of dump valve? Could it be that my tuner didn't know that and the egr is now permanently shut? I guess it's not good for the turbo?
What else could it be?

[davebb]

Originally Posted by kobom

Listen here: https://www.youtube.com/watch?v=-fxfS8E5Z-E
It occurs during gas pedal lift-off when the boost is gaining it's pressure, around 1500-2000 rpm. When doing the liftoff in higher rpm range then there is no noise. It sounds like the excessive boost has no place to escape other than back to the turbocharger. That started after remap, which included dpf and egr removal. Map was done by professional company with 15 years experiance with hundreds if not thousands of customers over the years.

What I've found from another forum:

Carful getting the EGR mapped out. Make sure they know what they are doing if they do. On the 185, the egr valve is opened when you lift off the throttle to dump boost pressure into the exhaust. If they map it out completely, you could loose driving refinement and possibly stall the turbo. best solution is EGR mapped out but retain lift off part and then you will be very happy.

Right, after doing some more research, checking the live data parameters,etc there is one problem with blanking the Egr valve.
On most vehicles, egr valve has only one purpose and that is to recycle the exhaust fumes. Unfortunately on Toyota landcruiser, it also acts as a Turbo pressure release valve( dump valve). That means that when releasing the throttle after acceleration, the excess pressure from turbo that remains in the intake system is being dumped trough egr valve back into exhaust system. When the egr valve is disabled or blocked, the excess pressure has nowhere to go and its being forced back to the turbo compressor and its putting strain on the blades.

Is it true that the Euro 4 D5 uses EGR as a sort of dump valve? Could it be that my tuner didn't know that and the egr is now permanently shut? I guess it's not good for the turbo?
What else could it be?

Yes it does sound like Turbo surge,
take it back to them and get them to sort it,
they may have the car boosting to high at to low rpm,
can you see were the dpf has been cut out ?
Dave

[Rich850R]

It won’t pass an MOT anyway now