Smoking Xantia 1.9TD

soupy_sam · Post by **soupy_sam** » 12 Apr 2005, 01:47

When I had to pull off quickly at high revs in my Xantia 1.9 Turbo Diesel I noticed in my mirror a nasty looking cloud of browny grey smoky muck left behind.
Is this indicating a problem?????

mattpc · Post by **mattpc** » 12 Apr 2005, 01:50

not necessarily. Turbo D's kick out a bit of muck under load anyway, especially if lots of crap has build up on the turbo (wastegate?) from driving around town. I find mine runs much cleaner when it's been on the motorway for a few hundred miles than it does if I pootle around town and then suddenly boot it. Sorry the explanation is not very scientific but I hope it puts your mind at rest.

soupy_sam · Post by **soupy_sam** » 12 Apr 2005, 01:53

Thanks have been pottering round for a while and haven't booted it for ages . You have put my mind at rest thanks

Post by **Peter.N.** » 12 Apr 2005, 02:45

It's probably an accumulation of soot in the exhaust system as mattpc says, good idea to give it a good hammering just prior to MOT (or on way to) makes the exhaust look much cleaner. My previous XM used to leave a black line of soot on the road sometimes, looked as though I had been burning the tyres

fastandfurryous · Post by **fastandfurryous** » 12 Apr 2005, 17:05

Driving style has a major effect on the cleanliness of XUD (and TUD) engines. My mother used to have a 1.4D pug 106 which would fail the emissions test every single year, with a very high (sometimes off the scale) reading. By adding a squirt of injector cleaner, and then driving down the motorway in 3rd for 5 minutes, it would pass no problems.
Conversley my 405 has hardly any emissions at all.. but then I do drive it quite hard most of the time.
Giving an XUD, especially a turbo, a good hoofing every now and then is definitely good for it.

soupy_sam · Post by **soupy_sam** » 12 Apr 2005, 23:49

Think you might be right I do tend to be a 50 mph max driver. Will have to go daft and give it some welly.

ghostrider · Post by **ghostrider** » 12 Apr 2005, 23:57

You don't have to forgo your 50 limit, just nail it to the rev limiter in 2nd for a bit [:D] [:D] [:D] [:D] [:D] it sounds horrible, if the cam belt is iffy don't do it but it does run better after
Pete
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soupy_sam · Post by **soupy_sam** » 12 Apr 2005, 23:58

Just put a cam belt on 5 weeks ago

np · Post by np » 13 Apr 2005, 00:33

They need a good trashing every now & then.I do about 400 miles a week at the moment,so plenty of use,but it still is a bit smokey.I had a new exhaust rear box in Febuary,that made a lot of difference to the smoke,hardly any after it was fitted,so the old one must have been quite clogged up.I also find that when its due for a service it becomes more smokey.It nearly faied the MOT on the smoke,but i didnt have time to service it.It had always been well below the smoke/emission levels for the last 3 MOT`s(having been serviced a week before each).
I`m going to service this w/end,that should get the smoke down a bit,though it`s not to bad.I also find Wynn`s Diesel injector cleaner,or smoke reducer to be very good.About £5 for 500ml,add a whole bottle to a tank full or fuel every 3k miles.

paranoid · Post by **paranoid** » 13 Apr 2005, 02:26

On the old xant, tried various cleaners etc but after various thrashings etc the longest lasting cure was after putting a few litres of veg oil in the tank, don't know why but it seemed to work.[;)]

fastandfurryous · Post by **fastandfurryous** » 13 Apr 2005, 06:49

Nailing the engine on the rev limiter certainly has the desired effect. A 106 1.4D in 3rd holds 70mph on its limiter, so you don't even have to break the speed limit to do it!
Because veg oil is a slightly slower burn, you tend to get peak cylinder pressure a bit later than ideal, so it's similar to having the timing a tad retarded. This reduces emissions a little, and can get the exhaust a little hotter, which tends to promote complete combustion of any remaining unburned hydrocarbons (or carbohydrates in the case of the oil!) This is the same principal as US emissions equipment that injects air into the exhaust manifold: It tends to promote complete combustion of unburned fuel, and hence cleans up the emissions.

jeremy · Post by **jeremy** » 13 Apr 2005, 13:06

If veg oil is slower burn shouldn't you advance the injection point to allow slightly more burning time?
jeremy

Kowalski · Post by **Kowalski** » 13 Apr 2005, 14:45

US emissions equipment that injects air only injects the air to dilute the pollutants in the exhaust. If you dillute your pollutants they can pass emissions tests more easilly it was really a cheat. The cleanest engines that Europe and Japan produce don't have any need of air injection.

soupy_sam · Post by **soupy_sam** » 14 Apr 2005, 00:15

[:D] WOW gave it a thrashing in 2nd as suggested. The whole of the road was lost in a cloud of sh*t for about half a mile, then it cleared and there was no smoke from the car.
A few unhappy pedestrians though
Have also put some veg oil in which seens to work well
Thanks guys

fastandfurryous · Post by **fastandfurryous** » 08 May 2005, 03:11

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Kowalski

US emissions equipment that injects air only injects the air to dilute the pollutants in the exhaust. If you dillute your pollutants they can pass emissions tests more easilly it was really a cheat.
<hr height="1" noshade id="quote"></blockquote id="quote">
No, Sorry, you're wrong on this one. The air injection system introduces additional oxygen into the 500+ degree exhaust gas so that if there are unburned hydrocarbons present, there is oxygen available to promote complete combustion. Combustion is effectively instant, as the exhaust gas is above the auto-ignition temperature for the hydrocarbons present.
The system is effective, but has it's problems. Not only does it sap some power from the engine for the high-pressure air pump (typically a few horses) but it also makes the exhaust manifold somewhat hotter, which has meant problems with reduced component life (usually cracking of the manifold)