Hi Folks

 

Facing a weird problem. I have a skoda superb elegance 2.0 TDI. Every day morning when i leave for office i have to give a long start before the engine starts and when it does there a lot of bluish smoke that comes out of the emission for a few seconds. This also happens sometimes when the car is parked for a long time (>8 hours). I took it to the authorized service centre and kept the vehicle there for a week since this issue would only come in the morning. They finally said that the entire fuel line and all its parts needs to be changed. Total cost estimate - approximately 5500 GBP. 

 

I then took it to a Bosch service centre and they also kept it for a week. They also could not figure what was wrong. They checked the glow plug, Fuel filter, fuel pump etc. They said that most probably its an issue with the fuel pump which needs to be replaced, but they cannot be sure as they cannot diagnose the issue since it occurs only once in the morning and there are no error codes generated in VCDS.

 

So now not sure what the issue is.. any ideas.

Blue smoke makes me think of burning small quantities of oil. If this only happens first thing, it appears to be a "leak down" issue, leading to oil getting into the inlet and exhaust ports.

 

Slow starting makes me think of a fuel pressure issue, which the VAG service centre can test for, but they have to think of looking there, OR a glow plug issue but I wouldn't automatically think of that in India unless you live in the Himalayan foothills?

Thanks for the response. The bosch service centre was also mentioning the pressure issue, but he said he could not see any issue on VCDS and hence was not sure. His suggestion was to wait for the problem to become more accute so that they would be able diagnose the issue better. Not sure how to take this forward. 

Being a 2010 car in India, I'm guessing it's the PD injection system rather than common rail.

 

Any air leaks in the fuel lines? Even a pinhole is enough for the system to lose prime and make starting hard. Given that the fuel lines are cheap, I'd start by replacing all the flexible lines to and from the fuel filter housing. Fit a new fuel filter too if that hasn't already been done.

 

Did the Bosch service centre test the injectors on the bench?

 

The blue smoke would worry me a bit: that's oil smoke. It may be unrelated to the starting problem. Check the condition of the shaft on the turbo: any play here is a problem. It would be useful to take the lower hose off the intercooler too and drain any oil that has collected in there.

 

The more worrying possibility for the oil is that the piston rings are worn so oil is getting into the combustion chamber from the sump. This would cause the blue smoke and the loss of compression could help explain the poor starting performance. Ask the service centre to inspect the cylinders with a borescope.

Or, as an easier option for the bore wear suggestion, ask one of the 2 (probably Bosch because they'll definitely have the right compression tester) to do a "dry and wet compression test". If they don't understand that, then they either can't do it or can't interpret the results or both!

Just to update this is CRDI engine. Also the Bosch service centre did not test the injectors on Bench. So i guess i will take it back to Bosch service centre and start with changing the fuel filter and lines. Actually they had suggested that but i did not agree to change the filter as the same was just changed as part of annual service just 2 months back.

Maybe there is something wrong with DPF? Blue-ish smoke is during regen.

Hello!

Just to update this is CRDI engine. Also the Bosch service centre did not test the injectors on Bench. So i guess i will take it back to Bosch service centre and start with changing the fuel filter and lines. Actually they had suggested that but i did not agree to change the filter as the same was just changed as part of annual service just 2 months back.

I'm not a mechanic at all but am used to troubleshooting technical problems in other fields. My first question here would be: did any of these issues start about two months ago?

 

Cheers,

Steve

When my car started to struggle in the mornings they found out at the service that it was a floppy flywheel and misalignment with sensors.