C5 x7 EGR unit, what's inside ?

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belaprops
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Joined: 05 Dec 2019, 23:20

C5 x7 EGR unit, what's inside ?

Unread post by belaprops »

I'm trying to fault find and establish what is inside the EGR module on the C5 x7 diesel 2Ltr.
I presumed the actuator on the side moves a valve inside, but with a lot of electrical wires going in...is there another electronic valve inside.

I have a problem where the engine drops in revs in a jumping manner, and it looks like a feedback loop of something between the airdoser valve and the EGR valve or valves.

As the airdoser closes to force air from the EGR into the engine but somehow there is not enough from either making the engine drop in revs after which it goes back and repeats the drop again and again. I heard the phrase kangaroing used.

If anyone has any suggestions why this kangaroing is happening then I'm all ears. When driving it manifests itself as a hesitate of the engine

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EDC5
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Re: C5 x7 EGR unit, what's inside ?

Unread post by EDC5 »

I think there is a stepper motor in the EGR module and perhaps a position senor to relay the actual position back to the ECU.

Whilst I can't recommend blanking the EGR valve off with a simple plate for legal reasons, you could maybe try it as a 'diagnostic aid' to see if the behaviour stops or changes in some way? Then at least you’ll know if you’re in the ballpark.

Does your engine have the 'double doseur' or single?

moizeau
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Re: C5 x7 EGR unit, what's inside ?

Unread post by moizeau »

If it's the same as the 1.6hdi it's a stepper / servo motor that operates a mechanical butterfly. You can take them apart and test each 1/2 separately.
Not a great picture but on page 1 you can see the 2 halves, the very black pic is the motor side.
viewtopic.php?t=64723

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KennyW
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Re: C5 x7 EGR unit, what's inside ?

Unread post by KennyW »

Her C5 has a single doser.

belaprops
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Re: C5 x7 EGR unit, what's inside ?

Unread post by belaprops »

Hi guys, thanks for the replies, but are you all saying there are two gates or valves the the EGR.
I found a blanc plate on the exit port of the EGR, removed it and my kangaroing has stopped. Probably because it can't choke the engine now the EGR is open.

Oh, Bela is a man's name lol

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myglaren
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Re: C5 x7 EGR unit, what's inside ?

Unread post by myglaren »

belaprops wrote:
18 Jun 2020, 13:23
Oh, Bela is a man's name lol
Béla Lugosi
Béla Lugosi

A very famous one too!

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Paul-R
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Re: C5 x7 EGR unit, what's inside ?

Unread post by Paul-R »

And this was my second thought.
Béla Bartok (photographed in 1927)
Béla Bartok (photographed in 1927)

There was a bust of him in front of the hotel we stayed in 2011 in the small town of Jimbolia in Romania. He was born in the nearby town of Sânnicolau Mare.
103_1254a.JPG