2.4D (2005 on) Check request EGR

[5cilinder]

After 2 minutes idling the egr is being shut off
At mine engine this is noticeble with a slight hum/vibration if you listen /look under the hood
Incar its barely noticeble anymore since the new front mounting
Now i want to know if this hum/vibration is a defect or a "feature"
I already cleaned the valve but noticed no difference
I would apreciate it if people with an euro 4 d5/2.4d want to check for the after 2 minutes idling hum/vibrition under the hood
Euro 3 engine owners i dont know for sure if the egr is also deactivated after 2 minutes ,but if they want to check we know for sure

[5cilinder]

Nobody?

[kenny37]

on my d5(185) i get this buzzing noise that goes on for a minute after shut down had always thought it the swirl motor but now ive got the arm fitted i can see its not that. so sorry i cant tell you what it is but yes it seems to be normal , if anything on a volvo is classed as normal..

[5cilinder]

That buzzing noise after shutdown is the callibrating of the throttle valve
And 1 out of 5 shutdowns the swirlvalve gets callibrated

But what i asked was the little hum/vibration with RUNNING engine wich starts after exact 2 minutes idling when the egr is shutted off
Could you or others check that?
Its not that difficult

I have the suspision that when the egr is shutted off the throttle gets partly closed to lower the air/fuel ratio as much as possible without egr polution wich creates resonance

[5cilinder]

Still nobody who wants to open the hood for 2 minutes to confirm or denail the humm/vibration?
Or did i do something wrong?

[outnumbered]

can not help you out this time.
mike

[5cilinder]

Why not?
Just idle the engine for 2 minutes after a drive and look under the hood ,im also curious if this is the case for an euro 3 engine

[5cilinder]

I guess its a no ;-)

[5cilinder]

Im realy dissapointed that nobody wanted after several times asking to open the hood and idle the engine for 2 minutes after a drive to see if there was vibration or not
Same as the request if people experienced fuelcutoff lag with throttle release after the dpf softwareupgrade

Its a non effort to just release the throttle and confirm if there is lag or not

Now i just could after those frustrations not post my findings after i dismemberred the inlet to see for myself whats going on but thats not me

Anyway:

What happens is this: when the EGR is working at idle the throtle is almost closed to create pressure difference for the egr to suck in more than otherwise could.
After 2 minutes the the EGR valve closed and the throttle fully opened
With the pipe removed between the mixplenum and valvecover there was no vibration , wich rules out the egrvalve in itsself so the throttle was the next suspect
Placed the black pipe back an took the intercoolerhose of at the throttle side
After 2 minutes the throttle opens fully when the egr valve closes and there was a loud resonance sound with a bit of vibration and with the hose disconnected it was almost a tuba when i placed a few fingers over the inlet resonance was all gone !
So i suspect because of a certain airspeed/pressure there is a change in laminair to turbulence in the airstream wich resonates because of a certain diameter.

So this leaves me to conclude that its a "feature" or a design flaw , it also could be that with other engines there is a slight difference in airspeed wich gives no vibration/resonance but people dont notice because it only comes up after 2 minutes of idling or in my case a rica remap with egr disabled wich caused me to think there was timing advance at idle wich wasnt the case it was the airresonance due to an open throttle when the egr is shut off

Even i know now whats causing what im still curious if other euro 4 engines also experience this

[outnumbered]

but then if you did not post your findings others would be just as frustrated as you where.
mike