*Shite old diesel obviously ;)

My 1.9td XUD engined Xantia failed MOT today on emissions, black smoke on 
acceleration (not bad though).

Since then, I've changed air filter (was slightly dirty) bunged some STP 
Stop Smoke in the tank and thrapped it a few miles.
I was wondering what else would help for the retest ?
Oil and filter were changed 300 miles ago, fuel filter a couple of thousand.

I was wondering whether "adjusting" the throttle cable a bit might help, or 
leaving the filter out for the duration of the test.
If the worst comes to the worst, would messing with the enrichment screw on 
the pump help, most people just up the fuelling for more power and more 
smoke, I was wondering whether the opposite would be true, and if it would 
damage the engine over the 2-3 miles to and from the MOT station :)

It'll probably pass tomorrow, but I'm thinking ahead/the worst.

-- 

Tony Bond / UncleFista

www.bradford7.co.uk

Love is like a snowmobile, speeding across the frozen tundra.
Which suddenly flips, pinning you underneath.
At night the ice-weasels come...

On Tue, 22 Jul 2008 20:03:28 +0100, Tony (UncleFista)  
 wrote:

> *Shite old diesel obviously ;)
>
> My 1.9td XUD engined Xantia failed MOT today on emissions, black smoke  
> on acceleration (not bad though).
>
> Since then, I've changed air filter (was slightly dirty) bunged some STP  
> Stop Smoke in the tank and thrapped it a few miles.
> I was wondering what else would help for the retest ?
> Oil and filter were changed 300 miles ago, fuel filter a couple of  
> thousand.
>
> I was wondering whether "adjusting" the throttle cable a bit might help,  
> or leaving the filter out for the duration of the test.
> If the worst comes to the worst, would messing with the enrichment screw  
> on the pump help, most people just up the fuelling for more power and  
> more smoke, I was wondering whether the opposite would be true, and if  
> it would damage the engine over the 2-3 miles to and from the MOT  
> station :)
>

It won't damage it but unless it's overfuelling because there's no  
compression then it won't help.

> It'll probably pass tomorrow, but I'm thinking ahead/the worst.
>


CHeck the boost pressure,

"Duncan Wood"  wrote in message 
news:op.uepk6kzdhaghkf@lucy...
> On Tue, 22 Jul 2008 20:03:28 +0100, Tony (UncleFista) 
>  wrote:
>
>> *Shite old diesel obviously ;)
>>
>> My 1.9td XUD engined Xantia failed MOT today on emissions, black smoke 
>> on acceleration (not bad though).
>>
>> Since then, I've changed air filter (was slightly dirty) bunged some STP 
>> Stop Smoke in the tank and thrapped it a few miles.
>> I was wondering what else would help for the retest ?
>> Oil and filter were changed 300 miles ago, fuel filter a couple of 
>> thousand.
>>
>> I was wondering whether "adjusting" the throttle cable a bit might help, 
>> or leaving the filter out for the duration of the test.
>> If the worst comes to the worst, would messing with the enrichment screw 
>> on the pump help, most people just up the fuelling for more power and 
>> more smoke, I was wondering whether the opposite would be true, and if 
>> it would damage the engine over the 2-3 miles to and from the MOT 
>> station :)
>>
>
> It won't damage it but unless it's overfuelling because there's no 
> compression then it won't help.
>
>> It'll probably pass tomorrow, but I'm thinking ahead/the worst.
>>
>
>
> CHeck the boost pressure,


or

1st Do not adjust the fuelling of the pump by breaking the seal or adjusting 
the diaphragm spring tension on the boost valve where the air pressure pipe 
connects to the pump. If you want to reduce the fuel rate simply and 
reversibly without touching any of the pump settings then :- Disconnect the 
boost pressure pipe that goes to the fuel pump from the turbo and pop into 
it a small plug such as a small length of round steel bar.    Slip another 
length of matching hose over the other end of the plug, fix securely with a 
couple of clips so it just looks like a pipe joiner and connect back to the 
pump.  Now the boost pressure will never reach the pump so the pump will not 
attempt to up the fuel metering rate to match the extra air the engine is 
being supplied with via the turbo as the revs increase, so reduced smoke. 
The performance will be way down as you drive the car on the road but the 
tester who only starts and drives the car a short distance in the garage, 
the temp lost performance will not show up.  Once test over remove plug and 
reconnect the boost pile as original.

Adjusting the cable will do little as the tester will often operate the pump 
by hand so will push the arm all the way to the stop.

Having said that, are you sure the smoke the tester saw was not just carbon 
particles that had been sitting in the exhaust pipe due to town driving ?  I 
take it it had a good run before you took it for the test ?  I know from 
experience a few full bore blasts in the test bay do not clear all loose 
particles.

Gio

"Gio"  wrote in message news:g66muc$qkg$1@news.datemas.de...
>
> "Duncan Wood"  wrote in message

Rightyo, I'll check boost pressure and check for leaks, then if the worst 
comes to the worst I'll block the boost pressure pipe from the pump to turbo 
:)

Thanks muchly, I'll report back when the debacle is over :)

-- 

Tony Bond / UncleFista

www.bradford7.co.uk

Love is like a snowmobile, speeding across the frozen tundra.
Which suddenly flips, pinning you underneath.
At night the ice-weasels come...

Tony (UncleFista) wrote:
> *Shite old diesel obviously ;)
> 
> My 1.9td XUD engined Xantia failed MOT today on emissions, black smoke 
> on acceleration (not bad though).
> 
> Since then, I've changed air filter (was slightly dirty) bunged some STP 
> Stop Smoke in the tank and thrapped it a few miles.
> I was wondering what else would help for the retest ?
> Oil and filter were changed 300 miles ago, fuel filter a couple of 
> thousand.
> 
> I was wondering whether "adjusting" the throttle cable a bit might help, 
> or leaving the filter out for the duration of the test.
> If the worst comes to the worst, would messing with the enrichment screw 
> on the pump help, most people just up the fuelling for more power and 
> more smoke, I was wondering whether the opposite would be true, and if 
> it would damage the engine over the 2-3 miles to and from the MOT 
> station :)
> 
> It'll probably pass tomorrow, but I'm thinking ahead/the worst.
> 
Just rev the knackers off it on the way to the MOT station. Full 
throttle on the redline in 1st, 2nd and third. Smoke will soon clear. 
Also make sure the engine is as warm as possible before the MOT test - 
more often than not they just wait til the oil temp is at 80 deg and do 
the test, if you can get the engine thoroughly warmed up it'll probably 
stand a much better chance of passing.

-- 
Pete M - OMF#9

BMW 325i SE Touring
Range Rover V8 Turbo

"Wait! We can't stop here, this is Bat Country"

"Tony (UncleFista)"  wrote in message 
news:udDhk.11210$ec5.4090@newsfe30.ams2...
>
> "Gio"  wrote in message news:g66muc$qkg$1@news.datemas.de...
>>
>> "Duncan Wood"  wrote in message
>
> Rightyo, I'll check boost pressure and check for leaks, then if the worst 
> comes to the worst I'll block the boost pressure pipe from the pump to 
> turbo :)
>
> Thanks muchly, I'll report back when the debacle is over :)
>
>

report ? :)

"Sarah"  wrote in message 
news:koCdnQswf8sJ-BbVRVnyjQA@bt.com...
>> Thanks muchly, I'll report back when the debacle is over :)
>>
>>
>
> report ? :)

Oooops, sorry 'bout that :)

After a good service, blat etc. it was still over the 3.0 limit.
I adjusted the throttle stop to stop it opening quite as much, until it just 
scraped through the test.
I was gonna put it back to how it was, but there seems to be no loss of 
power or anything, just less smoke.

I'm of the opinion that a previous owner had been messing...

It's still a shite, smokey old diesel though :)

-- 

Tony Bond / UncleFista

www.bradford7.co.uk

Love is like a snowmobile, speeding across the frozen tundra.
Which suddenly flips, pinning you underneath.
At night the ice-weasels come...

"Tony (UncleFista)"  wrote in message 
news:PKLik.28222$9I1.24856@newsfe16.ams2...
>
> "Sarah"  wrote in message 
> news:koCdnQswf8sJ-BbVRVnyjQA@bt.com...
>>> Thanks muchly, I'll report back when the debacle is over :)
>>>
>>>
>>
>> report ? :)
>
> Oooops, sorry 'bout that :)
>
> After a good service, blat etc. it was still over the 3.0 limit.
> I adjusted the throttle stop to stop it opening quite as much, until it 
> just scraped through the test.
> I was gonna put it back to how it was, but there seems to be no loss of 
> power or anything, just less smoke.
>
> I'm of the opinion that a previous owner had been messing...
>
> It's still a shite, smokey old diesel though :)
>
>

Old diesels eh :)

"Tony (UncleFista)" wrote:
> 
> "Sarah"  wrote in message
> news:koCdnQswf8sJ-BbVRVnyjQA@bt.com...
> >> Thanks muchly, I'll report back when the debacle is over :)
> >>
> >>
> >
> > report ? :)
> 
> Oooops, sorry 'bout that :)
> 
> After a good service, blat etc. it was still over the 3.0 limit.
> I adjusted the throttle stop to stop it opening quite as much, until it just
> scraped through the test.
> I was gonna put it back to how it was, but there seems to be no loss of
> power or anything, just less smoke.
> 
> I'm of the opinion that a previous owner had been messing...
> 
> It's still a shite, smokey old diesel though :)

I always see this puff of black smoke when a diesel car is accelerating.
Also in new, "modern", expensive diesel cars, e.g. top range mercedes.

"johannes"  wrote in message 
news:488C2569.3DAF0199@siz368568508efitter.com...
>
>
> "Tony (UncleFista)" wrote:
>>
>> "Sarah"  wrote in message
>> news:koCdnQswf8sJ-BbVRVnyjQA@bt.com...
>> >> Thanks muchly, I'll report back when the debacle is over :)
>> >>
>> >>
>> >
>> > report ? :)
>>
>> Oooops, sorry 'bout that :)
>>
>> After a good service, blat etc. it was still over the 3.0 limit.
>> I adjusted the throttle stop to stop it opening quite as much, until it 
>> just
>> scraped through the test.
>> I was gonna put it back to how it was, but there seems to be no loss of
>> power or anything, just less smoke.
>>
>> I'm of the opinion that a previous owner had been messing...
>>
>> It's still a shite, smokey old diesel though :)
>
> I always see this puff of black smoke when a diesel car is accelerating.
> Also in new, "modern", expensive diesel cars, e.g. top range mercedes.

Basically a result of manurfacturers trying to reduce NOx by using 
inefficiently large amounts of EGR.

The very latest cars you wont see with this problem as their DPF's will be 
filtering the soot out, only to be pulled up in the highstreet at the kerb 
afew miles on when the DPF is blocked solid..!

Tim..