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306 HDi - sooty exhaust - Andrew-T
My usually reliable indie declares himself outwitted by a combustion imbalance on my car: 99T showing 37K miles, with oil/filter changes every 6K, coolant changes, etc. For the last 1000 miles a grey cloud had been visible in the r/v mirror when accelerating, and gobs of soot are sometimes ejected at the rear.

Other data: oil consumption not measurable between changes; fuel has been up to 60mpg but is falling; starting and running are normal; temp gauge normally just below 80° but went up to 95° in a traffic jam recently.

Just had its 36K service, with fuel and air filters, and things have improved (cloud not seen so far), but indie says it's not quite right and he would need the Pug diagnostic to sort what he believes is an electronic problem. Any suggestions?
306 HDi - sooty exhaust - Sooty Tailpipes
I see this all the time, I don't think you need worry!
306 HDi - sooty exhaust - DL
I would tentatively say all is well and there is nothing to worry about.

The PSA HDi engine isn't the cleanest on the road. The 36k service you have just had done goes a fair way to putting right any problem areas that might cause excess smoke.

If the cloud reappears, then it's time to worry.
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306 HDi - sooty exhaust - dieselhead

Air filter would have had to be really badly choked to cause the smoke and airflow meter should compensate anyway so i would look for other causes.
Smoke under load is more likely to be caused by the Exhaust gas recurculation valve sticking open or boost pressure leakage -both of which cause over rich fuel/air mixture and smoke.
Other possibilitys are a broken or contaminated air flow meter . should be possible to check that the filament inside isn't broken or dirty.

306 HDi - sooty exhaust - Ross Lavery
Have you considered the turbo?

We had a 307 DW10 In with exactly the same problem as youre describing mate, but this had only 15k miles on it. Changed the Turbo after diagnosing. I take it this is when you accelerate hard? Diesels always emit some smoke, and I agree with the above comment somewhere that the HDi isnt the cleanest engine!!

Peugeot Master Tech (Been working on them too long now!)

1997 Mitsubishi Lancer Evo 5 GSR
1998 Y
306 HDi - sooty exhaust - update - Andrew-T
After a week away including a 300-mile drive, I have just taken the car to Pug dealer for a diagnostic check. The soot cloud had largely disappeared after the service, and the car seemed to be running well. The check found nothing, at least nothing needing a £300 part! EGO apparently OK. Indie presumes that the ECU must have been responding to inaccurate demand data of some sort. All's well that ends well, I suppose .. ..
306 HDi - sooty exhaust - second update - Andrew-T
For those who may be interested, this long-running problem seems to have been cured (tho 50 miles may be too soon to count chickens). Over the last 18 months the sootiness slowly became worse; consumption worsened by 10% and idling was usually accompanied by blue smoke and a strong smell of fuel. Although the car has done only 48K I decided to have a new cambelt (and fuel pump) at 6½ years old. I asked my indie (the same one) to sort the fuelling, even tho Pug diagnostics had twice said No Problem. He adjusted the timing on the camshaft and hey-presto - no smoke, smoother running, perhaps better performance (tho that was not bad anyway). Time will tell if consumption is back where it should be. So - so far, so good.

By the way, cost: belt and pump, £50. All-in cost, £200 inc.VAT.
306 HDi - sooty exhaust - second update - Andrew-T
"new cambelt (and fuel pump)" = water pump, of course ...

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