Chriso Posted August 11, 2007 Share Posted August 11, 2007 Hi, My 300 TDi Discovery failed it's MOT this week on the smoke test. The best result was 3.2 (I think the target is less than 3.0) My garage has suggested I book it in next week for a retest and they have stated that they will "back the pump off" Will this be effective, and what actually will they do? Most threads on this forum deal with increasing the fuelling with an associated turbo boost to supply more air. I guess I could clean the intercooler, buy a tank of expensive DERV, run some fuel additive through - or even get around to doing the tappets. Any thoughts? Chris. Quote Link to comment Share on other sites More sharing options...
western Posted August 11, 2007 Share Posted August 11, 2007 get some Redex or Millers injector cleaner & check a good dose in the tank & go for a good long hard drive, get the engine really working hard then go straight to the retest Quote Link to comment Share on other sites More sharing options...
davie Posted August 11, 2007 Share Posted August 11, 2007 my personal favourite method to try and reduce emmisions - about 20 - 30 miles driving as hard as i dare in 3rd or 4th gear,,,get the engine really working hard up the biggest hills you can find nearby and then get test,,,,god knows my 200 tdi smoked enough and always managed to scrape through after that tender loving driving! Quote Link to comment Share on other sites More sharing options...
Les Henson Posted August 11, 2007 Share Posted August 11, 2007 A higher than recommended dose of injector cleaner, change the oil, and get the engine nice and hot before going back for the retest. It helps to bung some veg oil in the fuel as well, though not more than 20%. Les. Quote Link to comment Share on other sites More sharing options...
RRX Posted August 12, 2007 Share Posted August 12, 2007 New air filters help with smoke reduction and as has been said some injector cleaner and a bit of veg oil Quote Link to comment Share on other sites More sharing options...
wizard Posted August 12, 2007 Share Posted August 12, 2007 When they say they will back the pump of, they mean they will restrict the amount of fuel going through the pump. By adjusting the power adjustment screw (undoing it a halfturn or so) you limit the amount of fuel being burnt, and therefore reduce your emissions. A few years ago my disco smoked like hell when it went for its MOT, i took the power screw out a whole turn and the Disco wouldn't rev over 3000rpm sailed through the emissions. Regards wizard Quote Link to comment Share on other sites More sharing options...
pinny Posted August 12, 2007 Share Posted August 12, 2007 i dont think you have said has the egr valve been removed or is this still on the vehicle mine smoked until i removed this also removed cat defender front pipe is a direct replacement as others said a dose of redex or similar may help but the egr valve maybe stuck open if its still on vehicle remove it or blank it off it will make a difference chris Quote Link to comment Share on other sites More sharing options...
Chriso Posted August 12, 2007 Author Share Posted August 12, 2007 i dont think you have said has the egr valve been removed or is this still on the vehicle mine smoked until i removed this also removed cat defender front pipe is a direct replacement as others said a dose of redex or similar may help but the egr valve maybe stuck open if its still on vehicle remove it or blank it off it will make a difference chris Sorry, yes EGR plate fitted. Before this it REALLY smoked under load! Quote Link to comment Share on other sites More sharing options...
Chriso Posted August 12, 2007 Author Share Posted August 12, 2007 Wizard, Many thanks for the info and diagram, I don't have anything like it even on my RAVE discs. Would it make sense to adjust the smoke adjustment screw as per your pic? Cheers Chris. Quote Link to comment Share on other sites More sharing options...
wizard Posted August 13, 2007 Share Posted August 13, 2007 I would back off the power screw by 1/4 of a turn first, if it still smokesa lot then adjust the smoke screw,but remember what you ahve do just incase you need to put it back again. wizard Quote Link to comment Share on other sites More sharing options...
Chriso Posted August 28, 2007 Author Share Posted August 28, 2007 Hi all, Just to close the thread, thanks for all your advice! I did as Wizard suggested and backed off the power screw a quarter of a turn. Happy days, I now have 12 months MOT. Chris. Quote Link to comment Share on other sites More sharing options...
LR90 Posted August 28, 2007 Share Posted August 28, 2007 Good result, congrats Chris and thanks for sharing. You may not be the only one that finds the technique useful Quote Link to comment Share on other sites More sharing options...
BogMonster Posted August 28, 2007 Share Posted August 28, 2007 Time to wind it back up 1/2 turn then, for another 50 weeks Quote Link to comment Share on other sites More sharing options...
nicks90 Posted August 29, 2007 Share Posted August 29, 2007 the other option is to take off the little boost pipe that fits on the injection pump from the turbo - so that when they floor it, the pump doesnt know its on boost and doesnt chuck in any extra fuel...... get your ticket, push the pipe back on the pump and away you go Quote Link to comment Share on other sites More sharing options...
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