2005 TiD rough idle and white smoke

[dave08]

Hi guys.
I picked up my 9-3 a few days ago after a scheduled full maintenance (distribution kit, water pump, oil brake, engine oil, etc, etc)
The mechanic also cleaned the EGR valve and I cleaned the MAP sensor when I got home.
One of the things I asked him to check were the glow pugs, because lately the car expelled a lot of white smoke while the engine was cold
and the car shakes a bit while idling during 1 minute until getting warmer.
During maintenance the mechanic told me he replaced all 4 glow plugs because 3 were bad (I guess it's normal after 13 years),
but the next day I still got some smoke and a little bit rough idle, even though much less than before.
Today I also experienced that again.

I'm thinking about:
1) some bad glow plug was installed - unlikely.
2) Throttle body needs cleaning ? Sometimes I experience a little hesitation/burst while accelerating hard.
could it also cause the white smoke and rough idle while cold?
3) Need to disconnect the battery so that the ECU does some new math to optimize combustion while cold? Don't even know
if the EDC16 works like that.
4) ...
Any one experienced this?
Thanks a lot!
Regards
Dave

[Audax]

Shaking while idle is generally either the intake air temp sensor or the map sensor failing (I forget which, the sensor setup changed over the years on the 2.20. Removing them and cleaning them up would help if that is the problem.

[dave08]

Thanks for the reply.
I already cleaned  the MAP sensor after maintenance with no visible improvement. Don't even know where the intake air temp sensor is located   
But the shaking (more like a misfire to me) only lasts a bit (30 seconds or less than a minute). If it was a sensor, shouldn't this occur always?
Thanks and regards.

[Audax]

There's a case that when one of those sensors isn't working it uses a default value for 30 seconds or so and then changes that value to something else. The effect is not noticeable and will not generate an engine management light. I'm forgetting the details somewhat though! Have you got a fault code reader as pulling the fault codes might be a good way forward.

[dave08]

Hm...that's interesting...and it could explain that behaviour. I'll connect the opcom tomorrow, but I don't remember reading any errors the last time I used it. I'll get back to this thread.
Thanks!

[dave08]

Hello.
So a while ago I connected the OPCOM and, once again, no DTC errors.
Still get some white smoke but less than before fitting the new glowplugs,  but the rough idle (seems more like a misfire) persists until it warms a bit. I think the air temperature sensor was providing the correct temperature which was the same on the SID (parked in the underground garage).

The curious thing.
One thing I forgot to mention is that the rough idle has been going on for some years actually, but in very curious situations.
-If the outside temperature is high (about >25 C), there was no  rough idle.
-If the outside temperature is low (< 10C), there was  no rough idle.
Anywhere in between or if the engine temperature is "mild", than there's the rough idle.

Without a DTC this is getting very hard to troubleshoot.
Any ideas please?
Thanks again.
Regards

[dave08]

Disconnected battery, even less smoke and shaking.
Maybe the ECU only now "learned" something new after the glow plugs were fitted. I'll get back to this topic in a few weeks.

[Audax]

Oh, I just realised something. I wasn't paying attention to this post, you have the 1.9 diesel? If so then you are supposed to tell the car using Tech-II when injectors have been replaced so that it will re-calibrate the ECU.

[dave08]

Thanks for the reply, but I'm talking about glow plugs not the injectors

[Audax]

Sorry, I'm now getting threads muddled up. I'll go and sit in the corner for a bit!