White smoke in a very specific circumstance
Discussion
Afternoon all. A bit of an odd one which I thought might interest people/give me some clues?
We have a 2013 Panda 4x4 diesel multijet, 112K, excellent full service history. It uses no oil, and fuel consumption is good.
It's used for school runs (10 miles e/w) and most short journeys. The school run is on A roads in the main and includes about 2-3 miles of dual carriageway driven at 70 mph. On some occasions (certainly not every time) and only one way down the dual when I've braked and gone round the roundabout at the end of the dual (Tingewick bypass on A421 heading towards Buckingham if anyone knows it) as I accelerate away I get plumes of white smoke for maybe 5 seconds - enough to make following cars drop back, anyway!
It's really peculiar. The rest of the time the car's perfectly well-behaved. The exhaust is clean and not sooty. Anyone any ideas at all? DPF not finished regen? Turbo problem? Injectors? The more I read the more I get confused!
We have a 2013 Panda 4x4 diesel multijet, 112K, excellent full service history. It uses no oil, and fuel consumption is good.
It's used for school runs (10 miles e/w) and most short journeys. The school run is on A roads in the main and includes about 2-3 miles of dual carriageway driven at 70 mph. On some occasions (certainly not every time) and only one way down the dual when I've braked and gone round the roundabout at the end of the dual (Tingewick bypass on A421 heading towards Buckingham if anyone knows it) as I accelerate away I get plumes of white smoke for maybe 5 seconds - enough to make following cars drop back, anyway!
It's really peculiar. The rest of the time the car's perfectly well-behaved. The exhaust is clean and not sooty. Anyone any ideas at all? DPF not finished regen? Turbo problem? Injectors? The more I read the more I get confused!
cuprabob said:
You can bet white smoke out of the exhaust if the DPF is carrying out a regeneration.
So my working theory based on this, is that when I drive it, which is less frequently than Mrs BF, because I like to give it a decent Italian tune it occasionally triggers a dpf regen which starts just after the bypass as the car gets fully up to temp on the bypass after say 7 miles. Does that make sense?Bonefish Blues said:
cuprabob said:
You can bet white smoke out of the exhaust if the DPF is carrying out a regeneration.
So my working theory based on this, is that when I drive it, which is less frequently than Mrs BF, because I like to give it a decent Italian tune it occasionally triggers a dpf regen which starts just after the bypass as the car gets fully up to temp on the bypass after say 7 miles. Does that make sense?Curveball - only happens after going down the hill? Assuming you are travelling on a very light / no throttle? This will cause a high vacuum in the intake. A faulty PCV valve could allow excess oil to enter the intake, which is then ingested as you accelerate again. Also worth checking the oil level.
Eta: you mentioned its a diesel, unsure if the fiat has a throttle.
Eta: you mentioned its a diesel, unsure if the fiat has a throttle.
LarJammer said:
Curveball - only happens after going down the hill? Assuming you are travelling on a very light / no throttle? This will cause a high vacuum in the intake. A faulty PCV valve could allow excess oil to enter the intake, which is then ingested as you accelerate again. Also worth checking the oil level.
Eta: you mentioned its a diesel, unsure if the fiat has a throttle.
Oil burning tends to be blue smoke.Eta: you mentioned its a diesel, unsure if the fiat has a throttle.
There's a slight downslope down to the roundabout at the end of the DC, so reasonably firm braking down from say 50-60 after I've initially lifted off. Then around the perimeter of the roundabout as there's often someone doing a Max Verstappen down the outside from L2. It's only when I start to pull away from the roundabout up a gentle slope that I get the James Bond white smokescreen for a few seconds.
GreenV8S said:
cuprabob said:
Oil burning tends to be blue smoke.
In practice it can be hard to tell the difference between water/petrol/oil just based on the color when you're watching through the mirror.
Hmm, smoking is back. I think it would pay for the Man to take a look at it - smelled a bit burnt outside when I parked up yesterday. Still only in that one circumstance.
Oil's right at the top of the dipstick - don't suppose it's as simple as an occasional oil surge after reasonably heavy braking is it?
Oil's right at the top of the dipstick - don't suppose it's as simple as an occasional oil surge after reasonably heavy braking is it?
Bonefish Blues said:
Hmm, smoking is back. I think it would pay for the Man to take a look at it - smelled a bit burnt outside when I parked up yesterday. Still only in that one circumstance.
Oil's right at the top of the dipstick - don't suppose it's as simple as an occasional oil surge after reasonably heavy braking is it?
If the oil level is raising itself, that’s a sign of an incomplete DPF regeneration. The increased fuel levels for the regen are ending up in the sump when it’s interrupted, for whatever reason.Oil's right at the top of the dipstick - don't suppose it's as simple as an occasional oil surge after reasonably heavy braking is it?
I wonder if the car maybe has an injector fault - white smoke on a diesel is a symptom. Could also explain why only partial regens are occurring, and the fuel level is rising.
Worth at least getting the codes read to investigate further.
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