Hi there, new to the forum but a long term reader/researcher.

 

Looked around but not seen much similar on the forum. I apologise in advance if it's been posted before and I'm just being blind. 

My Black Edition Quattro has started smoking at around 2750RPM, the smoke seems thin, white with maybe a blueish tone.

Car is a starship at 238,000 miles with full main dealer service history (every 6-10k miles) and 3 timing belt changes with the most recent at 236,000 miles. 

No smoke on idle, no smoke at any other time, fuel efficiency maybe not as good as it could be but tolerable at 30MPG - 35MPG.

At a loss at what to check, I have access to live data diagnostics and read injector values which seemed within suitable ranges (-0.68 / +1.54) although the injector that read +1.54 was cylinder 1 initially and upon further testing diagnostics read cylinder 4 as 1.54 and the others all in -0.68 - 0.58 etc.

Smoke seems to start at 2750RPM and clears after 3500, DPF showing 0% soot accumulation and 500km since last regen. No loss of power, no strange engine noises. 

Any advice would be greatly appreciated. 

 

Cheers 

-D 

Edited August 31, 2025Aug 31 by Depph

There are plenty of forum topics Darren referring to white smoke. Search them out and you will discover the main cause on a diesel is water leaking from EGR cooler into engine.

Blue smoke usually means oil is burning. so test the compressions as a first step.

3 hours ago, Depph said:

Hi there, new to the forum but a long term reader/researcher.

 

Looked around but not seen much similar on the forum. I apologise in advance if it's been posted before and I'm just being blind. 

My Black Edition Quattro has started smoking at around 2750RPM, the smoke seems thin, white with maybe a blueish tone.

Car is a starship at 238,000 miles with full main dealer service history (every 6-10k miles) and 3 timing belt changes with the most recent at 236,000 miles. 

No smoke on idle, no smoke at any other time, fuel efficiency maybe not as good as it could be but tolerable at 30MPG - 35MPG.

At a loss at what to check, I have access to live data diagnostics and read injector values which seemed within suitable ranges (-0.68 / +1.54) although the injector that read +1.54 was cylinder 1 initially and upon further testing diagnostics read cylinder 4 as 1.54 and the others all in -0.68 - 0.58 etc.

Smoke seems to start at 2750RPM and clears after 3500, DPF showing 0% soot accumulation and 500km since last regen. No loss of power, no strange engine noises. 

Any advice would be greatly appreciated. 

 

Cheers 

-D 

Hi monitor the EGT sensors on live data if the readings dont rise quickly when revved the sensor is probably on its way out which would cause it to run lean at certain rpms.

Steve.

52 minutes ago, Stevey Y said:

Hi monitor the EGT sensors on live data if the readings dont rise quickly when revved the sensor is probably on its way out which would cause it to run lean at certain rpms.

Steve.

Thanks Steve, will check this out ASAP 👍🏻

On 8/31/2025 at 4:48 PM, Stevey Y said:

Hi monitor the EGT sensors on live data if the readings dont rise quickly when revved the sensor is probably on its way out which would cause it to run lean at certain rpms.

Steve.

Checked the EGT Steve and all seems within normal range, I now have the car booked in to check turbo and seals as i suspect that's where the oil is entering the exhaust system.

Have also asked for a compression test just incase.

Will check in with any updates 

 

Thanks again 

- D

Edited September 6, 2025Sep 6 by Depph

Quick update, turns out there was a huge air leak in the EGR pipework, one of the solid pipes with "flexi" sections had split on one of the flexi sections. Have fixed the pipe and the car seems to have stopped smoking. Will monitor it over the coming weeks and if the issue returns I'll continue to investigate, but for now all seems good. 🙏🏻