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Discussion Starter #1 (Edited)
Hi,

I've just bought a 156 jtd 16v SW. Really nice car...It has all the looks, leather interior etc. etc. etc. EXCEPT.... for the motor control system failures I'm sometimes getting AND some strange noise I sometimes hear.

First about the Motormanagement errors: I get this every few times I drive, most of the times after 5 minutes driving, but can also be half an hour. Sometimes 3 days no problems. Occurs most of the times when speeding up a little bit, or when gas peddle is at 100%, to accelerate (or when cruise control resumes again).

What has been done:
1.
went to Alfa dealer and hooked it up to the examiner. Turbo pressure sensor gave incorrect value according to the guy. So he replaced the sensor (was very dirty because of exhaust gasses/egr..). Problem occured again. so made a new appointment.

2.
Again examiner showed up the turbo pressure sensor that gave a faulty value. Because I also hear sometimes some mechanical noise when my rpm is around 2800 rpm and because the turbo pressure sensor was really dirty I asked the guy to clean the EGR. I'm not sure if they cleaned it very througohly, but they told that the valve was indeed dirty (of course...). I'm also very shamed when I accelerate from 80 to 120 km/h, especially when it's dark I can see the black dirt in the headlights of the cars that are behind me... So I thought this was EGR related...

3.
tomorrow new appointment with the dealer to replace some other sensor (think the overboost sensor?, located near the radiator at the front of the car). I will also ask them to double check all hoses related to the turbo and air intake, and the air intake itselves.

When accelerating in second gear, I *sometimes* hear some mechanical grinding like sound. I started to hear it just before shifting up to the third gear when I'm off the throttle. Dealer guy says it's some air resonation because I pointed out it was during the time when I suddenly get of the gas throttle...However I also hear it sometimes when just accelerating in the 2nd gear. I've tried to make a sound recording, but had no success yet to have a clear recording. Problem is, it's not always the same and some other times much louder. I had also a few cases (2-4) where all power was gone. All of these times this was NOT related to any engine error popping up on the display.

Maybe if you have any ideas I can pass it on the the alfa guy looking at my car.

btw: EGR is one of the last models: electrical valve. Earlier models can be capped with a blank plate when they give problems, with this engine (156 jtd 16V) of a later (third/fourth??) generation, it can only be done by software if I'm correct, and then not for 100% close the valve. Not sure if these problems (strange sound and the motor management errors) I'm having are related to eachother...


regards,
BellaMacchina
 

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Hi & welcome to AO:thumbs:

I've moved your post to the 156 technical lounge so you should get lots of answers there:D
 

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Hi there & Welcome! :p
 

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Discussion Starter #4
also reading about corrossion on the vanes of the turbo... Could that also explain the noise I sometimes hear and the motor control system failure? I do NOT experience any lack of power during accelleration, except then when the motor management gets in error and runs in "safe mode"...
 

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Discussion Starter #5
third time the turbo pressure sensor has been replaced. nr 1 and nr2 replacements where used sensors...Now they've ordered a new one. Hope that's it, but I'll only be sure in one or two weeks ;-)
 

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Discussion Starter #6
And as expected, again in error this morning. Called to dealer to have the car in for a few days so they can check more than they did before.

My guess (and I'm a total car tech noob) is that it's the turbo itself, the actuator of the vanes...Also because of the rattle and cracking sound I sometimes hear...Maybe it gets stuck a little bit, so that the vanes do not open immediately when rev is around 2800 rpm, causing too high turbo pressure.

You any ideas?


thanks.
 

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I hate to say it but it does sound like the turbo itself, you've had everything else checked (sensors/pipework) ... so it sounds like that is the thing ...
 

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Discussion Starter #8
and not the actuator itself that controls the variable vanes within the turbo, that is a little bit sticky or rusty?

I'll place a bet with the dealer guy...

just based on reading the several messages on the forums, like this one: http://www.alfaowner.com/Forum/tuning-and-upgrades/114470-147jtd-pre-cat-removed.html and the sound I hear sometimes...

I hope that's it, it's all warranty but better that they just need to clean or replace the actuator then the turbo...
 

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and not the actuator itself that controls the variable vanes within the turbo, that is a little bit sticky or rusty?

I'll place a bet with the dealer guy...

just based on reading the several messages on the forums, like this one: http://www.alfaowner.com/Forum/tuning-and-upgrades/114470-147jtd-pre-cat-removed.html and the sound I hear sometimes...

I hope that's it, it's all warranty but better that they just need to clean or replace the actuator then the turbo...
If it's all warranty then the more newer bits the better ...
 

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Discussion Starter #11
picked my bella up a few hours ago. Dealer told the turbo pressure was too high and if I'm correct he adjusted something on the rod and or spring that control the vanes of the variable geometry of the turbo. He also measured while driving and he noticed a too high turbo pressure (systemattically???). Not sure if I got the same power as I had, probably a little bit less because turbo pressure overall is lowered a llittle bit so that the engine won't go into error again. However, still enough power so far. If it was really this, I'll know for sure within the next week. He also told me that could also cause the sound I'm hearing. Didn't hear it again, but in the past I could also not reproduce it anytime. So probably this was the fix to my problem.
 

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Great News :thumbs: (touch wood)
 
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