Right i've had this since buying the car and had no luck with the garage I bought it from and regards to warranty.

The car at the time was untuned, the car now has a dpf delete + remap (215hp ) and the problem is still present - not worsened or got better.

The problem is usually when the car is under load - it does not happen under full throttle. When accelerating say from 1200rpm to 2000rpm a dump valve noise can be heard and will happen 2 or 3 times in succession, during this period the power drops during the noise and comes back again when the noise goes -so roughly half a second. This gives like a kangarooing effect whilst driving but i don't think it's noticeable to anyone watching.

The other time it happens the car makes a chatter sound like a car that has a BOV however no power is lost during this period?

I've used torque pro which shows no error codes, dealer at the time had no error codes and no lights come up on dash.

Any suggestions?

I'm based in Huddersfield if anyone can recommend a specialist if needed.

Cheers,

Ben

Here's a video showing 1 part of what happens. In this instance there is no power loss during acceleration but you can here the noise. (turn up speakers) http://youtu.be/Levwkx4empE

here's a longer example http://youtu.be/hfYXOjpfyl8

My 2.0 M-Jet does this too but not as often as yours. Mines had the DPF removed and re-mapped but not as high as yours. Think it's just a release of excess pressure, mine mostly does it coming off the throttle and I like it.

Rigby said:

My 2.0 M-Jet does this too but not as often as yours. Mines had the DPF removed and re-mapped but not as high as yours. Think it's just a release of excess pressure, mine mostly does it coming off the throttle and I like it.

Click to expand...

Mine did it prior to dpf delete and remap, however I wouldn't mind except sometimes it loses power which is a cause for concern.
Off to a diesel specialist tomorrow then will try Fiat (really don't want to with extortionate prices)

Ours is a standard config 165,2009. Does pretty much as per your vid and the others descriptions. On the throttle between 1200 and 2000 rpm.
Have been trouble shooting it for a couple of days now and this is what I have observed.Its a bit of a story so bare with me

I changed the timing belt some months back but it was slightly off and was causing the car to go into limp mode on deceleration.
Now the issue we are discussing was not happening as much with the timing slightly off but the limp mode was more of an issue so it had to be sorted out.

Redone the timing a couple of days ago and advanced the timing a little. Now this time the issue we are talking about was a lot more severe! The limp mode is sorted but the low rpm issue was severe enough to make the car judder and pull back for a second.

Since then, I put the timing back to default. The issue is still there BUT its a heck of a lot less severe. Does it occasionally whilst barely noticing any loss of power.


If anyone can make any sense of that it would be great.

Quick update.
I disconnected the pierburg turbo boost valve and sure enough it does not create that low rpm grind.
My hunch is the turbo is at fault.If you take off the inlet pipes to expose the turbo prop, I noticed movement on mine and swear it is rubbing off the walls of the housing.
So it seems a turbo recon is on the cards.

My unconfirmed report back today is that it is indeed the wastegate valve or bow off valve that is causing this issue.
I unplugged it and went for a quick drive around the block and indeed no judder/hesitation/scratchy noise as per vid above.

Where is it on the 2.0? I'm sure on every other Bravo its right on top

Right under the turbo. If you remove the manifold heat shields you'll spot the arm that attaches to the turbo body. This is what opens and shuts the wastegate on the turbo.

There is an adjuster screw on the turbo body to allow the actuator not to open the wastegate fully, but its a pain to get to.My plan is is to stop the actuator from opening the wastegate too much.For the moment with it disconnected its bliss as the wastegate is closed and am getting full on boost.

Was reading over on the alfa forums that you can equally disconnect the pipe that leads from the pierburg valve to the actuator,and this will give you full on boost also BUT could spell trouble down the line with head gaskets etc.

Was it easy to disconnect? May try it on mine, it doesn't do it often would like to know if its causing any other problems.

To disconnect the actuator itself is very easy.You will spot a plug going into it if you look underneath the turbo body. Doesnt throw up any errors on the dash which is great and certainly wont cause a limp mode

But the low end pick up may not be to everyones satisfaction, but it could be that the ecu needs to relearn parameters. You need to keep the revs up. Just my observation of how it felt yesterday with the wastegate fully shut.

Anyways yesterday evening I managed a temp work-around to stop the actuator opening all the way and disconnected the ecu to allow it relearn. That screw I mentioned on the turbo housing is a pre-load for the actuator. Usually the actuators come with an adjustable arm which would have been easier I guess to adjust.

Will go out for a drive this morning and see how it feels to drive.

Ok,here is my final assessment on this issue.

From my understanding the wastegate on the turbo is open by default. In this position it is allowing the turbo to generate maximum boost and not allowing excess air to escape down the exhaust.

The manifold pressure is monitored and the pierburg picks up the pressure and sends it to the actuator attached to the turbo housing.If the manifold sensor senses too much pressure it closes the wastegate and allows excess air to escape down the exhaust.Pretty much standard behaviour.

The issue I have experienced (and others) it seems is that the wastegate is closing too much (allowing the boost not to build) and for a brief moment the actuator is either flapping open/shut or the ecu is not getting the required reading.

So here is what I have done to stop this from happening.
As written earlier if you unplug the connector on the actuator housing the issue goes away as the wastegate remains open and building boost, all the way,all the time when on the pedal.

Another solution which appears to have remedied this issue is the adjustment of the preload screw found on the turbo. The default position for this screw, allows the wastegate to close fully (and herein is the cause of my problem)
So by adjustment of the screw upwards, you effectively stop the gate from closing fully, and in my case it has worked.
I am not convinced entirely that it is the actuator that is at fault. Could be the pierburg sending the wrong signals or the manifold pressure sensor or a pipe faulty. But I have fitted a new pierburg valve and maf and the tubing all appears fine.

Here is a pic of the turbo in the 165, just for reference.
The yellow arrow is pointing to the adjustment screw I'm on about. There is an M6 or M7 nut that holds it in place. This needs to be loosened first and then with a thin screw driver,get some height on the screw to stop the hammer on the end of the actuator arm from coming down all the way.This will prevent the wastegate from shutting completely and hopefully fix this issue on the cheap.
It can be done without removing the turbo but you'll need go go gadget tools and fingers as thin as pencils.



If there is any change from my end I'll post back but for the moment the car is running sweet!

Sorry chaps,my explanation above isnt precise on the exact workings of the wastegate on our turbos.Hate giving misleading info

This link explains better how the turbos in our cars work..
http://turbo.honeywell.com/our-technologies/vnt-turbochargers/

Cars still behaving well though.

Any idea how many turns you applied to the screw when adjusting the actuator arm stop?

Right update from me and not a good one.
recently it had been getting worse.
Yesterday I gave the car full throttle on a nice road, as I changed gear I heard a loud dump valve noise followed by a aeroplane noise.......
now I have this: [ame]http://youtu.be/EvORANmacyA[/ame]
Any ideas what I've done?

Not quite sure what you mean by 'aeroplane noise', but if it sounds a bit like a police siren, then it's the classic sound of a turbo on the way out...

By the way had you previously done the waste gate actuator shaft screw adjustment in post # 13?

Yellow Peril said:

Not quite sure what you mean by 'aeroplane noise', but if it sounds a bit like a police siren, then it's the classic sound of a turbo on the way out...

By the way had you previously done the waste gate actuator shaft screw adjustment in post # 13?

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Nope, I hadn't seen this post get updated for some reason and only saw that post on Friday. Was going to get on it until that happened "/

OK I had a look at mine today. The actuator shaft stop adjuster screw was already showing some thread (approx 4mm) so it would seem the waste gate is already prevented from completely closing.

I'm minded to leave alone unless the symptoms worsen. And visibility and access to the screw are really difficult without unbolting the turbo...

Yellow Peril said:

OK I had a look at mine today. The actuator shaft stop adjuster screw was already showing some thread (approx 4mm) so it would seem the waste gate is already prevented from completely closing.

I'm minded to leave alone unless the symptoms worsen. And visibility and access to the screw are really difficult without unbolting the turbo...

Click to expand...

My car is off to a garage tomorrow. I'll mention it and show him the video, he sounded very competent on the phone about turbo's so maybe I'll find a solution?

I did wonder if it's a sign the turbo is on it's way out though?