Flooring the throttle on the wife's Xsara 1.9TD produces such a cloud of black smoke that we become invisible. Am expecting irate comments when they catch me up at the next lights!
Have changed all filters and tried Italian tune-ups to no avail.
Passed last MOT smoke test (just) on low sulphur diesel which should have been a cinch. Fuel consumption seems fine but maybe the injectors have had it on 84k miles?
Anything else worth checking before I bite the bullet?
[:(]
Out of Sight
Moderator: RichardW
Does it always happen or only occasionally? If the car is driven at a sedate pace around town with lots of idling in queues, traffic lights, etc, then there's inevitably a build up of unburnt fuel which can then produce the big cloud of smoke you describe. If it always happens then you probably need to check the injectors. If you've tried an Italian de-coke to no avail I think you may have to bite the proverbial.
Oscar
Oscar
If the engine is laboured on acceleration, low revs high gear, the engine will over fuel and produce excess black smoke. Try keeping the revs higher, above 2000 rpm, before flooring it.....it's less likely to labour and produce less smoke!
I tend to use a fifth gear smoke screen at low speeds to get tailgaiters off my rear!![:D]
You can see the fury in their eyes.[:(!][:(!]
I tend to use a fifth gear smoke screen at low speeds to get tailgaiters off my rear!![:D]
You can see the fury in their eyes.[:(!][:(!]
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Kowalski
- Posts: 2557
- Joined: 15 Oct 2003, 17:41
- Location: North East, United Kingdom
- My Cars: Ex 05 C5 2.0 HDI Exclusive 145k
Ex 97 Xantia 1.9TD SX 144k
Ex 94 Xantia Dimension 1.9TD 199k
The engine will not smoke from being laboured, not unless your injectors are in very poor condition.
I've had 2 TD Xantias and both will happilly pull from 25mph in 5th gear without smoke. The Older Xantia most noticeably produces smoke on boost above 3000 rpm. With the newer one you only notice smoke in other car headlights, and even then its above 3000 rpm full throttle on boost and only when the engine is cold.
Diesels shouldn't smoke noticeably if they are in good condition, remember smoke is unburnt fuel (and thus wasted fuel).
I've had 2 TD Xantias and both will happilly pull from 25mph in 5th gear without smoke. The Older Xantia most noticeably produces smoke on boost above 3000 rpm. With the newer one you only notice smoke in other car headlights, and even then its above 3000 rpm full throttle on boost and only when the engine is cold.
Diesels shouldn't smoke noticeably if they are in good condition, remember smoke is unburnt fuel (and thus wasted fuel).
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Kowalski</i>
The engine will not smoke from being laboured, not unless your injectors are in very poor condition.
I've had 2 TD Xantias and both will happilly pull from 25mph in 5th gear without smoke. The Older Xantia most noticeably produces smoke on boost above 3000 rpm. With the newer one you only notice smoke in other car headlights, and even then its above 3000 rpm full throttle on boost and only when the engine is cold.
Diesels shouldn't smoke noticeably if they are in good condition, remember smoke is unburnt fuel (and thus wasted fuel).
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Could you explain further how a diesel on full throttle doesn't inject an initial excess of fuel on heavy, full throttle, acceleration?
Take into consideration the following statement :
'The position of the control sleeve controls at what angle the spill port opens, and thus determines the amount of fuel injected, in other words it controls the metering. The control sleeve is moved in response to a combination of accelerator position and engine speed. The latter is determined by a mechanical governor.'
What else other than a change in timing and an increase in fuel would cause a diesel engine to accelerate.
The airflow isn't metered!
My car flew it's emmissions test at the last MOT, and that was with 180,000+ miles.
And yet, if I stick it in fifth at 20-25mph and floor the throttle, it will smoke!!
It pulls in all gears and as long as I don't labour it, I don't get black smoke. It will give a lot of newer cars a run for their money, suprising most with it's turn of speed.
I had the injectors inspected by a local diesel specialist about 15,000 ago...he said they were perfect. And I've had two MOT's since.
I understand that unburnt fuel dislays itself as a carbon emmission. As an Aircraft Propulsion Technician of 12 years I know a little about fuel and fuel metering systems.
If you could give me the tech to explain...I could have some egg on my face. And would be a wiser man for the privilege.[:I]
ref: http://www.cs.rochester.edu/u/jag/vw/en ... jpump.html
The engine will not smoke from being laboured, not unless your injectors are in very poor condition.
I've had 2 TD Xantias and both will happilly pull from 25mph in 5th gear without smoke. The Older Xantia most noticeably produces smoke on boost above 3000 rpm. With the newer one you only notice smoke in other car headlights, and even then its above 3000 rpm full throttle on boost and only when the engine is cold.
Diesels shouldn't smoke noticeably if they are in good condition, remember smoke is unburnt fuel (and thus wasted fuel).
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Could you explain further how a diesel on full throttle doesn't inject an initial excess of fuel on heavy, full throttle, acceleration?
Take into consideration the following statement :
'The position of the control sleeve controls at what angle the spill port opens, and thus determines the amount of fuel injected, in other words it controls the metering. The control sleeve is moved in response to a combination of accelerator position and engine speed. The latter is determined by a mechanical governor.'
What else other than a change in timing and an increase in fuel would cause a diesel engine to accelerate.
The airflow isn't metered!
My car flew it's emmissions test at the last MOT, and that was with 180,000+ miles.
And yet, if I stick it in fifth at 20-25mph and floor the throttle, it will smoke!!
It pulls in all gears and as long as I don't labour it, I don't get black smoke. It will give a lot of newer cars a run for their money, suprising most with it's turn of speed.
I had the injectors inspected by a local diesel specialist about 15,000 ago...he said they were perfect. And I've had two MOT's since.
I understand that unburnt fuel dislays itself as a carbon emmission. As an Aircraft Propulsion Technician of 12 years I know a little about fuel and fuel metering systems.
If you could give me the tech to explain...I could have some egg on my face. And would be a wiser man for the privilege.[:I]
ref: http://www.cs.rochester.edu/u/jag/vw/en ... jpump.html
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Kowalski
- Posts: 2557
- Joined: 15 Oct 2003, 17:41
- Location: North East, United Kingdom
- My Cars: Ex 05 C5 2.0 HDI Exclusive 145k
Ex 97 Xantia 1.9TD SX 144k
Ex 94 Xantia Dimension 1.9TD 199k
The injection pump on a pure mechanical setup (e.g. XUD9) is set up and calibrated not to put excess fuel into the engine at any time with a margin for error, it has to be this way. The down side to this is that under almost all conditions (except on a hot day at some massive altitude) the engine could safely have more fuel injected without smoking.
Mechanical injection turbo diesels dont have an air flow meter, they have a boost compensation device that allows greater fueling when the turbo is producing boost i.e. more boost means more fuel can be added. Whilst there is no air flow meter the engine does in fact compensate for air flow, I can tell when its time to change the air filter on my TDs because on a hot day they are down on power, i.e. on a hot day when the air is less dense the dirty air filter restricts air flow and the turbo can't produce boost. My Xantias end up down on power rather than becoming smoky. If the filters got really dirty they would smoke all of the time but I replace them long before that point.
Mechanical injection turbo diesels dont have an air flow meter, they have a boost compensation device that allows greater fueling when the turbo is producing boost i.e. more boost means more fuel can be added. Whilst there is no air flow meter the engine does in fact compensate for air flow, I can tell when its time to change the air filter on my TDs because on a hot day they are down on power, i.e. on a hot day when the air is less dense the dirty air filter restricts air flow and the turbo can't produce boost. My Xantias end up down on power rather than becoming smoky. If the filters got really dirty they would smoke all of the time but I replace them long before that point.
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Kowalski
- Posts: 2557
- Joined: 15 Oct 2003, 17:41
- Location: North East, United Kingdom
- My Cars: Ex 05 C5 2.0 HDI Exclusive 145k
Ex 97 Xantia 1.9TD SX 144k
Ex 94 Xantia Dimension 1.9TD 199k
Its either over fueling which would be a pump or pump calibration problem, or its injectors aren't atomising the fuel correctly which can make it smokey. Alternatively the timing could be out or the timing belt could be on its way out? Do you know when your cambelt was last changed?
If your catalyst was badly blocked would the car smoke badly? My thinking being that there would be boost, so the pump would compensate for the boost but there wouldn't be enough air actually going through the engine. Perhaps if the cat gets that badly blocked it would stop the turbo from working.
Does the car drive Ok, i.e. pulls strongly from 2000rpm and idles smoothly etc?
What is the fuel consumption like?
If your catalyst was badly blocked would the car smoke badly? My thinking being that there would be boost, so the pump would compensate for the boost but there wouldn't be enough air actually going through the engine. Perhaps if the cat gets that badly blocked it would stop the turbo from working.
Does the car drive Ok, i.e. pulls strongly from 2000rpm and idles smoothly etc?
What is the fuel consumption like?
It runs very well and returns about 45mpg.
Idling a little fast at just under 1,000rpm. Am pretty sure nobody tweaked the pump settings - maybe I can in the opposite direction.
I've got through quite a few glow plugs (7 in 3.5 years, 34,000 miles).
Turbo boost is very noticeable from 2,500 revs but so's the smoke!
Cambelt changed around 20,000 miles ago.
Good point re cat - still original. I hear some people change it for a straight pipe. I changed the main pipe & box recently - looks fiddly to remove the cat though but could be worth the effort - any tips?
Idling a little fast at just under 1,000rpm. Am pretty sure nobody tweaked the pump settings - maybe I can in the opposite direction.
I've got through quite a few glow plugs (7 in 3.5 years, 34,000 miles).
Turbo boost is very noticeable from 2,500 revs but so's the smoke!
Cambelt changed around 20,000 miles ago.
Good point re cat - still original. I hear some people change it for a straight pipe. I changed the main pipe & box recently - looks fiddly to remove the cat though but could be worth the effort - any tips?
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Kowalski
- Posts: 2557
- Joined: 15 Oct 2003, 17:41
- Location: North East, United Kingdom
- My Cars: Ex 05 C5 2.0 HDI Exclusive 145k
Ex 97 Xantia 1.9TD SX 144k
Ex 94 Xantia Dimension 1.9TD 199k
You shouldn't need to adjust your pump settings really, my '95 Xantia hasnt had its pump settings fiddled with and it isn't smoky. If your settings are as standard they shouldn't need any adjustment at all.
I'm sure somebody else on here had problems with black smoke on boost, I don't recall what the solution was but you might be able to search for the thread.
I'm sure somebody else on here had problems with black smoke on boost, I don't recall what the solution was but you might be able to search for the thread.