Diesel failed MOT on black smoke test- Help!!

Penny_Farthing_2

Hi
My Y reg Citroen synergie diesel failed its MOT because when the guy (at the council mot center) revved it to the red line tons of black smoke came out of the exhaust. It was off his scale. He suggested putting fuel conditioner in and running the car fast for 20 miles or so. We've done this and it's still smoking when the revs get to the red line. It may be wishful thinking but maybe there's not as much smoke? Hmm.
I was wondering what the problem was if this stuff didn't put it right. :huh: The man at the garage said it would be an expensive thing to fix if the conditioner didn't work. Would anyone know a ballpark figure for this kind of thing, please?
Trying not to panic,
PF

goldspanners

dont panic,it may not be as serious as he has made out,dont put any additives in just yet,they should be a last resort before mot time,run the car with high revs not necesarilly fast for a good while about 30 mins,this will help to clean exhaust,injectors and valves,also before doing this get it serviced changing the fuel and air filters,these will play a major part in reducing the smoke test it and see if it is smokey,if not then brilliant,if it is still a bit smokey try using a diesel injector cleaner that mixes with the fuel,i think comma make a good one cant remember the name though,put it in just before the mot,take it for another good run and then the mot centre,hopefully it should pass.
if none of this makes any differance then you might find it an expensive repair possibly replacing fuel injectors and pump.or it could be a case of the timing being out and needing set up properly.

Penny_Farthing_2

Thanks very much for that, Goldpanners. I've already put the stuff in the fuel but I'll check the air and fuel filters. It has a 12000 mile service interval and it's showing 8200 miles till the next one but it's still worth checking the filters, as you suggest. I'll also try high revs for 30 mins (deep joy for the neighbours, though). Perhaps I'll try to find somewhere else to do that!
Are we talking over or under £400 if I need fuel injectors/pump sorted, would you know, please.

goldspanners

to be honest probably over £400 for parts and labour.

Penny_Farthing_2

Oh dear.
Well let's hope the filters and the revving will do the trick, then.:D Thanks again for your help.
PF

dieselglider

Penny_Farthing wrote: »

I'll also try high revs for 30 mins (deep joy for the neighbours, though). Perhaps I'll try to find somewhere else to do that!

I hope you don't mean high revs when stationary, you'll stand a good chance of blowing the engine!! Take it for a good motorway blast, using 3rd gear to accelerate up to around 60-70mph for a bit so it's revving under load. If you can see smoke at the rear while doing so, it should gradually clear.
What sort of additive did you add? I have heard of very good results from using Cataclean.

Penny_Farthing_2

Thanks Dieselglider for clearing that one up - yes I thought it did mean while stationary! Can't remember what I used but it was in a small single use bottle. Will try all these fixes and see how things go. Thanks again-that could have been expensive!!

Conor_3

Take it for a long drive out and thrash it like you're The Stig test driving a Bugatti. Long hard acceleration in every gear. Remember when you finally stop to leave the engine idling for a minute to allow oil to circulate through the turbo as it cools.

Penny_Farthing_2

I think I might enjoy that, Conor. Pity it's a people carrier, though, and not one of these http://en.wikipedia.org/wiki/Tesla_Roadster :rotfl:

in2deep_2

As mentioned drive it hard, rev it up to the governor and hold it for a few seconds then change gear, don't worry it wont hurt, the engine will limit over revs, If you look in your mirror you will see clouds of black soot.
You should repeat this on the way to the test station.

..another tip/trick/crafty is to take out the air filter just for the MOT....don't say i said.

Penny_Farthing_2

OOOH I'm far too chicken to do that! Thanks for the revving advice, though - I was a bit worried about damaging the engine.