A6 2.5TDI Smoking + ultrasonically cleaning injectors

It doesn't do it massive amounts (not that I can see in the mirror from the
driver's seat) but a mate of mine has said that it smokes quite a bit, and
that it can be thick and black (yup, it's a diesel!).

Obviously it's the sort of thing you notice more at night than in daylight,
but this morning when leaving for work (engine had only been running a
couple of minutes up to this point btw) pulling away not particularly
quickly resulted in not particularly thick (but still noticeable) smoke in
the car behind's headlights. Obviously darkness and headlights do tend to
emphasise any smoke coming out of any car's exhaust though.

My question is this - does my engine (5-cylinder 140bhp 2.5TDI) have a MAF
sensor, and is this easy enough to take out and clean (should this be
neccessary), and if that's all ok, how much should I expect to have to pay
to get the injectors ultrasonically cleaned.

And is there much variation on the quality of ultrasonic cleaning services
available (I don't want some cowboys ****ing them up) or is it a
straightforward job that the machine takes care of with not much chance of
anything going wrong?

Btw, the car has just short of 127k on the clock, and has been regularly
serviced all its life (every 10k up to 50k at audi main delaer, then every
6k up to 94k with a new air filter and fuel filter every time, then at 105k,
114k, 125k, with one new air filter at 114k and a new fuel filter at 125k).
So I wouldn't say it's been neglected, though I have worried a little about
the time I've left it between oil changes (though it's been largely motorway
use) and the mileage the laster air filter and fuel filter did before
changing (20k and 30k respectively). Am I worrying about nothing on these
points? Is it the MAF sensor that needs cleaning, or is it time for
injector overhaul?

Peter
--
"The truth is working in television is not very glamorous at all. I just go
home on my own at night and sit alone and eat crisps."

AstraVanMan wrote:
> It doesn't do it massive amounts (not that I can see in the mirror
> from the driver's seat) but a mate of mine has said that it smokes
> quite a bit, and that it can be thick and black (yup, it's a
diesel!).
>
> Obviously it's the sort of thing you notice more at night than in
> daylight, but this morning when leaving for work (engine had only
> been running a couple of minutes up to this point btw) pulling away
> not particularly quickly resulted in not particularly thick (but
> still noticeable) smoke in the car behind's headlights. Obviously
> darkness and headlights do tend to emphasise any smoke coming out of
> any car's exhaust though.
>
> My question is this - does my engine (5-cylinder 140bhp 2.5TDI) have
> a MAF sensor,

Yes.



and is this easy enough to take out and clean (should
> this be neccessary),

Not really.
If it has failed, which I doubt because you have said nothing about a
drastic power loss, then it is probable that you will have to fit a
new one.



and if that's all ok, how much should I expect
> to have to pay to get the injectors ultrasonically cleaned.
>
> And is there much variation on the quality of ultrasonic cleaning
> services available (I don't want some cowboys ****ing them up) or is
> it a straightforward job that the machine takes care of with not
much
> chance of anything going wrong?
>


Before you go to any expense, first try a can of really effective
injector cleaner like Forte or Millers. Equally effective, and
cheaper, is a litre of ATF [automatic transmission fluid] for every 20
gallons of diesel in the tank. This is only needed once [a year
perhaps] and, in the case of ATF, will take the consumption of a
tankfull or two to work, but work it will.

Give it a go and report back after a thousand miles or so. You have
nothing to lose.

Huw


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> > My question is this - does my engine (5-cylinder 140bhp 2.5TDI) have
> > a MAF sensor,
>
> Yes.
>
> and is this easy enough to take out and clean (should
> > this be neccessary),
>
> Not really.
> If it has failed, which I doubt because you have said nothing about a
> drastic power loss, then it is probable that you will have to fit a
> new one.

No drastic power loss. It's performing as it should. Economy isn't
terrible either, but probably a good 5mpg down from what it should be.

> and if that's all ok, how much should I expect
> > to have to pay to get the injectors ultrasonically cleaned.
> >
> > And is there much variation on the quality of ultrasonic cleaning
> > services available (I don't want some cowboys ****ing them up) or is
> > it a straightforward job that the machine takes care of with not much
> > chance of anything going wrong?
>
> Before you go to any expense, first try a can of really effective
> injector cleaner like Forte or Millers. Equally effective, and
> cheaper, is a litre of ATF [automatic transmission fluid] for every 20
> gallons of diesel in the tank. This is only needed once [a year
> perhaps] and, in the case of ATF, will take the consumption of a
> tankfull or two to work, but work it will.

I think I tried some of that sort of stuff (not ATF) before - didn't notice
any significant changes. I've pondered the idea of putting it in a much
higher concentration than one bottle per tank (similar to redex direct into
the cylinders) but I'm worried about buggering something up (read the below
after a bit of googling):

"I had a vague thought about ATF in the back of my mind somewhere, I have
previously heard of someone using it neat, dribbled into the intake of a
running petrol engine as an upper cylinder valve cleaner but realised this
might result in a bent conrod or similar if attempted on a diesel, not that
the intake ports are accessible anyway. I hadn't heard of it being used
diluted in the fuel though and certainly didn't think it could take water
with it. I no longer run a car with an automatic gearbox, so that is a good
way of using up those couple of cans of ATF in my garage...I'd been
wondering what to use them for."

> Give it a go and report back after a thousand miles or so. You have
> nothing to lose.

I'm a bit worried about ATF - it won't have a snake oil effect, will it? If
it was significantly more effective than the injector cleaner stuff then I
might be tempted, but I'm a scaredycat, so I might spend a few more quid and
get the "proper" stuff.

Peter
--
"The truth is working in television is not very glamorous at all. I just go
home on my own at night and sit alone and eat crisps."

AstraVanMan wrote:
>
> I think I tried some of that sort of stuff (not ATF) before - didn't
> notice any significant changes.

But you need stuff that does actually work. I can vouch for the Fore
and for ATF, but I used the ATF at two litres in twenty gallons. The
effect of the ATF actually lasts a good 12 months in the engine it is
applied to. It even gets rid of white smoke at start-up if this is a
condition brought on by age and use rather than being like that from
the factory new.


>
>> Give it a go and report back after a thousand miles or so. You have
>> nothing to lose.
>
> I'm a bit worried about ATF - it won't have a snake oil effect, will
> it?

The point about snake oil is that it has *no* effect. Certainly ATF
will not harm your car and will provide the diesel with better
lubricity if nothing else.


If it was significantly more effective than the injector cleaner
> stuff then I might be tempted, but I'm a scaredycat, so I might
spend
> a few more quid and get the "proper" stuff.
>

A lot of the "proper" stuff is just snake oil. Or just oil. ATF on the
other hand is very good, high detergent oil.

Huw


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> > I think I tried some of that sort of stuff (not ATF) before - didn't
> > notice any significant changes.
>
> But you need stuff that does actually work. I can vouch for the Fore
> and for ATF, but I used the ATF at two litres in twenty gallons. The
> effect of the ATF actually lasts a good 12 months in the engine it is
> applied to. It even gets rid of white smoke at start-up if this is a
> condition brought on by age and use rather than being like that from
> the factory new.

No white smoke on start-up. Well, not that I've noticed anyway. Exhaust
points down, and I'm never in a position to see it when I'm starting the
engine!

> >> Give it a go and report back after a thousand miles or so. You have
> >> nothing to lose.
> >
> > I'm a bit worried about ATF - it won't have a snake oil effect, will
> > it?
>
> The point about snake oil is that it has *no* effect. Certainly ATF
> will not harm your car and will provide the diesel with better
> lubricity if nothing else.

I thought the point about snake oil is that it lingers in the system,
potentially causing future blockages??

> If it was significantly more effective than the injector cleaner
> > stuff then I might be tempted, but I'm a scaredycat, so I might spend
> > a few more quid and get the "proper" stuff.
>
> A lot of the "proper" stuff is just snake oil. Or just oil. ATF on the
> other hand is very good, high detergent oil.

Cool, that puts my mind at ease. I want it to have a really decent effect,
so I'd rather put more in and have more smoke in the short term, but a
longer lasting effect, rather than it just having a gradual effect - by tank
takes about 78 litres at most (so not quite 20 gallons) - would 2 litres in
a whole tank be too much (is there any potential damage it could do) or
should it be ok?

Also, you say you've tried it - have you tried on VAG TDI engines before?

Peter
--
"The truth is working in television is not very glamorous at all. I just go
home on my own at night and sit alone and eat crisps."

The message >
from "AstraVanMan" > contains these words:

> And is there much variation on the quality of ultrasonic cleaning services
> available (I don't want some cowboys ****ing them up) or is it a
> straightforward job that the machine takes care of with not much chance of
> anything going wrong?

Out of interest, I have an ultrasonic cleaner - what solvent do these
services use?

--
Skipweasel.
Being superstitious brings bad luck

AstraVanMan wrote:
>
> I thought the point about snake oil is that it lingers in the
system,
> potentially causing future blockages??

He-he :-) "Snake oil" is just a generic term for useless products.
AFAIK it originated in the Wild West when medicine salesmen sold quack
medicine as a cure-all.

>
>> If it was significantly more effective than the injector cleaner
>>> stuff then I might be tempted, but I'm a scaredycat, so I might
>>> spend a few more quid and get the "proper" stuff.
>>
>> A lot of the "proper" stuff is just snake oil. Or just oil. ATF on
>> the other hand is very good, high detergent oil.
>
> Cool, that puts my mind at ease. I want it to have a really decent
> effect, so I'd rather put more in and have more smoke in the short
> term, but a longer lasting effect, rather than it just having a
> gradual effect - by tank takes about 78 litres at most (so not quite
> 20 gallons) - would 2 litres in a whole tank be too much (is there
> any potential damage it could do) or should it be ok?

No potential damage and it will be OK. I would try a maximum of 1.5
litres at first. Use up threequarters of a tankful of the treated fuel
then top up with diesel only for the second tankful. By the time you
use most of the second tankful you should find a very significant
improvement. If not, try again. If it doesn't work then, the injectors
need calibrating. This is unlikely though not impossible.

As to speed. Nothing works instantly. Think of a washing machine full
of clothes. It takes a couple of hours to wash, then they need to dry
and be aired and ironed before they are clean and fit to be worn
again. Much less palarver is involved with useing an additive like ATF
to clean the injectors. Just apply, use and wait for results. Best to
forget about it for a week afterwards before checking the smoke.
Otherwise it is rather like watching paint dry or yourself growing
old; nothing much happens from minute to minute.



>
> Also, you say you've tried it - have you tried on VAG TDI engines
> before?
>

No but I have used it with good results in a Toyota high pressure fuel
system and various other diesel vehicles only on an 'as needed' basis.
Remember to mix well. I fill the tank about a third full and add a
third of the mixture, fill to half full and add half of the remainder
and then add the rest at around the 3/4 mark. No need to be *that*
precise but remember that when fuel is concerned "cleanliness is next
to Godliness"

Huw


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> > I thought the point about snake oil is that it lingers in the
> system,
> > potentially causing future blockages??
>
> He-he :-) "Snake oil" is just a generic term for useless products.

I sort of knew that, just got the impression that generally snake oil type
products end up causing blockages, like slick50 and the like.

> > Cool, that puts my mind at ease. I want it to have a really decent
> > effect, so I'd rather put more in and have more smoke in the short
> > term, but a longer lasting effect, rather than it just having a
> > gradual effect - by tank takes about 78 litres at most (so not quite
> > 20 gallons) - would 2 litres in a whole tank be too much (is there
> > any potential damage it could do) or should it be ok?
>
> No potential damage and it will be OK. I would try a maximum of 1.5
> litres at first. Use up threequarters of a tankful of the treated fuel
> then top up with diesel only for the second tankful. By the time you
> use most of the second tankful you should find a very significant
> improvement. If not, try again. If it doesn't work then, the injectors
> need calibrating. This is unlikely though not impossible.

The cambelt was done at 110k (17k ago) at a VW/Audi specialist, and the
timing properly checked on their fancy computer equipment. Is that what you
mean by calibrated (wrt timing) - or calibrated in a different way?

> As to speed. Nothing works instantly. Think of a washing machine full
> of clothes. It takes a couple of hours to wash, then they need to dry
> and be aired and ironed before they are clean and fit to be worn
> again. Much less palarver is involved with useing an additive like ATF
> to clean the injectors. Just apply, use and wait for results. Best to
> forget about it for a week afterwards before checking the smoke.
> Otherwise it is rather like watching paint dry or yourself growing
> old; nothing much happens from minute to minute.

Yeah, true. I'm just an impatient ****.

> > Also, you say you've tried it - have you tried on VAG TDI engines
> > before?
>
> No but I have used it with good results in a Toyota high pressure fuel
> system and various other diesel vehicles only on an 'as needed' basis.
> Remember to mix well. I fill the tank about a third full and add a
> third of the mixture, fill to half full and add half of the remainder
> and then add the rest at around the 3/4 mark. No need to be *that*
> precise but remember that when fuel is concerned "cleanliness is next
> to Godliness"

Ah, I get you - so it's got more chance of mixing more evenly throughout the
fuel? Cool.

Peter
--
"The truth is working in television is not very glamorous at all. I just go
home on my own at night and sit alone and eat crisps."

AstraVanMan wrote:
>>> I thought the point about snake oil is that it lingers in the
>> system,
>>> potentially causing future blockages??
>>
>> He-he :-) "Snake oil" is just a generic term for useless products.
>
> I sort of knew that, just got the impression that generally snake
oil
> type products end up causing blockages, like slick50 and the like.
>
>>> Cool, that puts my mind at ease. I want it to have a really
decent
>>> effect, so I'd rather put more in and have more smoke in the short
>>> term, but a longer lasting effect, rather than it just having a
>>> gradual effect - by tank takes about 78 litres at most (so not
quite
>>> 20 gallons) - would 2 litres in a whole tank be too much (is there
>>> any potential damage it could do) or should it be ok?
>>
>> No potential damage and it will be OK. I would try a maximum of 1.5
>> litres at first. Use up threequarters of a tankful of the treated
>> fuel then top up with diesel only for the second tankful. By the
>> time you use most of the second tankful you should find a very
>> significant improvement. If not, try again. If it doesn't work
then,
>> the injectors need calibrating. This is unlikely though not
>> impossible.
>
> The cambelt was done at 110k (17k ago) at a VW/Audi specialist, and
> the timing properly checked on their fancy computer equipment. Is
> that what you mean by calibrated (wrt timing) - or calibrated in a
> different way?

No, I mean taking the injectors out to spray and pressure test them.
Crack-off pressure falls off over time and also fuel volume injected
gradually increases, usually to the actual benefit of less noise and
more power to a point. That point is where soot emissions become
unacceptable to the extent that either you are concerned or it fails
the MOT soot test.

I don't know whether your engine is a standard unit or a Pumpe-deuse.
Either way, your mileage should not cause this kind of concern. But
you never know. There is a bit of luck involved with running any
engine.

If you are still concerned after doing the cheap additive trick as I
described, then take it to an MOT station and ask them to actually do
a soot test. They will be able to give you a proper measure of the
soot to either confirm your anxiety or take a load off your mind.


Huw


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> > The cambelt was done at 110k (17k ago) at a VW/Audi specialist, and
> > the timing properly checked on their fancy computer equipment. Is
> > that what you mean by calibrated (wrt timing) - or calibrated in a
> > different way?
>
> No, I mean taking the injectors out to spray and pressure test them.
> Crack-off pressure falls off over time and also fuel volume injected
> gradually increases, usually to the actual benefit of less noise and
> more power to a point. That point is where soot emissions become
> unacceptable to the extent that either you are concerned or it fails
> the MOT soot test.

Yeah, I think the fact that it's quite a freely revving diesel engine means
that the power is easily accessible and it's quite easy for it to overfuel a
bit.

> I don't know whether your engine is a standard unit or a Pumpe-deuse.
> Either way, your mileage should not cause this kind of concern. But
> you never know. There is a bit of luck involved with running any
> engine.

It's just a standard one. Proper old-skool design, dating back to 1991!

> If you are still concerned after doing the cheap additive trick as I
> described, then take it to an MOT station and ask them to actually do
> a soot test. They will be able to give you a proper measure of the
> soot to either confirm your anxiety or take a load off your mind.

As far as MOT soot tests goes it's fine - it's only when it's under load
under hard acceleration, or actually during acceleration generally, that it
smokes a bit. I'll give the ATF a try as you've suggested and let you know
how I get on.

Anyway, cheers for all the advice. Good, this internet thing, innit? I'd
happily repay the favour if you ever need any help with talking ****e or
telling mildy amusing stories.

Cheers,

Peter
--
"The truth is working in television is not very glamorous at all. I just go
home on my own at night and sit alone and eat crisps."