tweetyduck Posted August 23, 2010 Share Posted August 23, 2010 i gather if i remove the four bolts on the top of the diaphram and trun it a bit back anticlockwise i can turn down the fuel. However ontop of the cap is a nut visible from the outside before you take off the cap. Does this need to be turned at all? Thanks I get a bit of black smoke under acceleration when in the wrong gear and according to the web this is a sign of over fuelling and i need to tweak it back a tad. It was set at 90 and i've turned it to 45. Do i need to turn that one ontop as per the pic? Quote Link to comment Share on other sites More sharing options...
reb78 Posted August 23, 2010 Share Posted August 23, 2010 If this has worked Neill, there should be a pdf attached for you to have a read of. There is also an article in the tech section describing all of these adjustments, but the pictures are missing and it has got a little confused in translation from one forum to another i think. tdi pump tuning.pdf Quote Link to comment Share on other sites More sharing options...
Aragorn Posted August 23, 2010 Share Posted August 23, 2010 Why bother? The black smoke occurs because the engine doesnt have enough air, but at the same time, it also helps get the turbo spooled up, giving better response when your in the right gear. Unless theres clouds of it, i'd be leaving it alone. The engines already hugely underpowered, why would you want less power. If you've ever been behind a modern electronic derv you'll notice they emit tonnes of smoke when you peg the boot to the floor, smoke = power. As for the changes you've made (the diaphram), only affects on boost fuelling, so wont affect it much below the boost threshold and will really hamper your power once the turbo is up to speed, so likely wont change the smoke, and will just lose you power. You want to adjust the off boost fuel setting, which is controlled by the torx screw shown in your image. Turn it down too much though and it'll just become horrible off boost. Quote Link to comment Share on other sites More sharing options...
tweetyduck Posted August 23, 2010 Author Share Posted August 23, 2010 "why bother?" - was becuase it was bad, the Garage i initially went to said it was badly overfuelled. I might get the mechanic to look at it again on thursday when its in for the clutch. Thanks for the document reb. That tells me all i wanted to know and some things i don't.. I've been out for a drive and the smoke is slightly less and the power the same. I think i need to read that document,,,and understand it. At low revs when pulling off in the wrong gear theres a lot of smoke, so thats the torx screw setting? Question is should i turn it CW or CCW. I'm not going to play with any other settings now but it would be usefull to know. Quote Link to comment Share on other sites More sharing options...
reb78 Posted August 23, 2010 Share Posted August 23, 2010 Anticlockwise. It sets the position the top of the boost diaphragm sits at with no boost. Boost pushes the pin down effectivley leading to increased fuel supplied to the engine (read the bit in the pdf about the cone - linked to turning the diaphragm - for more detail on how). Turning the torx screw clockwise pushes the pin down to supply more fuel off boost, anti clockwise does the opposite. Read the pdf again - it took me a few reads to get it all! Whatever you do, record everything you do so you can put it back to how it was. Quote Link to comment Share on other sites More sharing options...
tweetyduck Posted August 23, 2010 Author Share Posted August 23, 2010 OK thanks. A few....i can see it taking a dozen...LOL. Lets say i go round a corner and choose 3rd rather than 2nd,,, then i get smoke. If i choose 2nd its fine. The smoke in 3rd goes away once i'm back up to higher revs. So that to me sounds like i should turn that screw a bit anti clock. Theres no black smoke when motoring fast. Theres no black smoke in the correct gear. Only in the wrong gear. Sounds logical ? Quote Link to comment Share on other sites More sharing options...
Aragorn Posted August 23, 2010 Share Posted August 23, 2010 Sounds like it. Presumably by "wrong gear" your letting the engine revs drop below ~1900rpm? The turbo doesnt really do much below there so you'll drop back to the low pressure fuelling, controlled by that screw. Looks like its in Section 3 of that pdf above. If you put the diaphram back (or even advance it if you want a bit more power) and wind the rest position screw back until your smoke has gone, you should have the best settings. Quote Link to comment Share on other sites More sharing options...
tweetyduck Posted August 23, 2010 Author Share Posted August 23, 2010 Thanks both. Will have a bash tomorrow and i'll make sure i know where i moved it from. Quote Link to comment Share on other sites More sharing options...
reb78 Posted August 23, 2010 Share Posted August 23, 2010 Yep. I agree with Aragorn. Do that and you should be fine. The diaphragm probably doesnt need touching and from your description, i wouldnt think you have to turn the screw back far. Quote Link to comment Share on other sites More sharing options...
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