[dave08]

Hello. I've been experiencing this for some time but it is getting worse. This year even during summer (bellow 30 degrees C), on a cold start, I got lot's of white smoke and rough idle until the engines warms up a bit. lately, with colder weather and if the temperature is around 5, 6 degrees C, the cars starts perfectly without smoke or rough idle.
If the outside temperature gets higher, or the engine has worked, stops, and then I restart after one hour or two, I get smoke and rough idle for a few seconds. So this is a temperature related issue, as the glow plugs and relay work fine (and were tested). The instrument cluster temperature gauge works fine, so I'm thinking If there is another temperature sensor that transmits information to the ECU or glow plug relay.
I've seen similar symptoms on Vectras and Astas with the Z19DTH and DT engines, and people say if they disconnect the coolant temperature sensor they force the glow plugs to work and the cars start fine. Please note that mine also starts fine when the temperature is lower, that's why I think this is a sensor related problem.

Any ideas please?
Regards.

 

[lizzard-t]

Hello dave08 just one thaught of mine
starter motor ?
It may sound ok , but I'm sure there's a few threads on here about some similar issues, and once the starter motor was changed all was well .
I had mine changed this year due to a loud clanking type sound when starting when car is warm ,
garage put it down to transmission noise , or DMF wear , but I asked them to change it , and the noise went away and the car started first time every time , which it had not done since owning it .

 

[dave08]

Hello dave08 just one thaught of mine
starter motor ?
It may sound ok , but I'm sure there's a few threads on here about some similar issues, and once the starter motor was changed all was well .
I had mine changed this year due to a loud clanking type sound when starting when car is warm ,
garage put it down to transmission noise , or DMF wear , but I asked them to change it , and the noise went away and the car started first time every time , which it had not done since owning it .

Thanks for the reply. hmmmm... but the car starts fine and at first attempt. For example, today, with 5 degrees C, there was very little white smoke and no rough idle at all. Later today, I bet I'll have more smoke and also rough idle for about 10 to 30 seconds. If the starter is the issue, how to explain the rough idle and white smoke when not so cold?
In my post I wrote that some people with astras and vectras "disconnect the coolant temperature sensor"
But they are having trouble to start the car when cold. Mine starts but my problem is the white smoke and rough idle and "mild" temperatures. Weird. I've been told the relay was fine, but maybe if the temperature isn't low enough it doesn't activate the glow plugs and I get those symptoms.
Ideas?
Thanks!

 

[dave08]

So here's my problem. See attach.
Cleaned it and running much much much better

 

[lizzard-t]

That's the mass air pressure sensor.which is always good to take out and clean.electrical contact cleaner and a cotton wall bud . due to the sensor.but at least you have seemed to of cured the problem.
Good work.

Sent from my TA-1024 using Tapatalk

 

[dave08]

That's the mass air pressure sensor.which is always good to take out and clean.electrical contact cleaner and a cotton wall bud . due to the sensor.but at least you have seemed to of cured the problem.
Good work.

Sent from my TA-1024 using Tapatalk

Unfortunately, not perfect. Yesterday I found that I still have more smoke than what was supposed to when air temperatures are not so low. But still, better than before. Maybe is the sensor that isn't working a 100% already, after more than 13 year of use, I wouldn't be that surprised. I wonder if a Tech2 can diagnose this sensor...