Hi all,

I posted up a wee while ago in regards to my car overfueling and that the tuning box might be causing this.

After finding out I can't turn down the tuning box I went and purchased a Fuel additive and followed the instructions and the advice from a fellow member on here and the car seemed to run a lot better and we went away for the day, upon accelarating a big black smoke screen came out the back, at first I put it down to the car cleaning itself out but 450 miles later the car still produces on occassion a black smoke screen on accelration, my oil is ok (first thing I checked) but I've got the MOT in a couple of weeks time and I'm starting to worry it will fail on the emmissions test, is it worthwhile taking the tuning box off, giving the car a hard drive to clean the soot out or again add the fuel additive.

Hope you can help?

I'd say give it time. Which fuel stuff did you go for? Mine runs religiously on millers diesel sport 4 which means I know my system is as clean as it can be (and any soot is merely just fresh unburnt fuel, not anything being "cleaned out" )

Thanks for the reply, the fuel additive is millars sport 4, I'm going to be adding another couple of measures this weekend as I'm using the car on a brisky run, would say not using the car very much at the moment be causing this ie I have done 445 miles in a week mainly runs to the borders, crail, car show down in biggar, but from Monday to Friday the car just sat outside the front door as I bike or take the bus to work.

Thanks once again for replying

What sort of tuning box is it? Take it off and it'll be a lot better. If you insist on running the tuning box then remove it for the MOT and put it back on afterwards.

it's called the orginal tuning box IIRC, sometimes when you drive normal and change up you see a wee bit of soot which seems to be normal with any other Fabia that I've been behind, do you sugges ttaking it off the now or say next week when the MOT is due?

Thanks for replying

I'd reckon this pretty much has to be the tuning box, because even the good ones work by increasing fuelling (just more scientifically than spoofing the engine into thinking it's always cold). However, when was the air filter last changed?

Yeah, I'd agree with that - mine has a Dragon, and it gets pretty sooty when the filter's dirty. All diesels smoke more when it gets warm as the air density decreases, but a PD160 and a regularly replaced / cleaned filter works wonders IME. And as I've stated many, many times before, my preference is for an OEM paper filter new every six months rather than any panel nonsense...

The filter is a green cotton filter, and was last changed/Cleaned in august, I still think it is the tuning box as the car never used to smoke as bad as it did when I stuck the box on, I'm going take it off this week I think and let the car return to 130 settings.

As far as I'm aware the car has always been a bit of smoky beast since I first stuck it on the rolling road, is it worthwhile maybe taking it to a autocentre like Kwikfit to try a emission test on the car??

Many thanks for the help once again

AUGUST!?! Get it cleaned! (Properly, mind, unless you've got the cash for a new MAF lying around!) I wouldn't take it anywhere like KF, as they're bound to 'find' something wrong, if you see what I mean... :thumbdwn:

Is the weather any warmer lately? Combination of warmer weather and dirty air filter would make it smoke.

Aye the weather is a bit warmer than normal up here, will have to get the strut brace off to clean the filter then.

Hi all,

Thought I would give a wee update on this problem.

A couple of weeks ago we took the car on a briskoda drive down to cumbria, first time the car has had a proper run for a while and reports from people on the trip said the car was smoky, might have been the fuel additive cleaning it out in the process.

On returning from the trip I noticed the car needed topped up with oil, so I purchased some oil and filled the oil level.

At the weekend the car had to go for the MOT and service, so took it up to Star where it the tuning box was taking off and all that was wrong with the car was a headlight out of alignment and the handbrake needed to be tighter, so I think I am putting this down to the tuning box overfueling the car.