Vehicle & Technical > Discovery
Black smoke?
jnoshea:
A bit of scouting around on the web and it seems that the part number for the intercooler to manifold hose that is needed when taking the EGR out is ESR2309. Trouble is, can't find somewhere that stocks all three bits to make up one order.
muddyweb:
James,
Just to add a bit of information..... The EGR valve mods won't have a huge effect on black smoke when you are accelerating hard off something like a roundabout.
This is (usually) a symptom of turbo lag...
On a diesel engine with all mechanical control like the 200 and most 300 tdi engines, the turbo is operated by the exhaust gas in the exhaust manifold. When you put your foot down hard, the injection pump throws a load more fuel into the system to make the engine go faster... because it is powered from the exhaust, and as such the boost is related to the engine revs, the turbo doesn't work any harder until the engine spins faster... so there is a slight delay in the boost increase as the engine comes up to speed. This is turbo lag... you often hear people talking about the turbo 'kicking-in'... this is when the boost pressure gets up enough to help the engine run faster and the power spirals upwards.
Now.. in the time between you hitting the pedal, and the turbo spinning up, there is an excess of fuel in the system... not all of this fuel is burnt in the cylinders because there isn't sufficient air from the inlet system to match the increased amount.... this shows up as a sooty cloud of smoke from the exhaust.
Hope that makes some sense !
There are some funky ways to negate turbo lag.. but they are all quite expensive ;-)
colintandy:
and just to add to the last
the black smoke can be controled in the fuel pump 200tdi at top of pump if you prize open the cap with a small screwdriver you will see a lock nut holding a screewable thread if you unlock and screw thread in clockwise this will increase/decrease smoke or unburnt fuel as the end of the thread is what the diaphram pushes up and down on under the 4 bolts on the top
i have a full bore exhaust and uprated intercooler and if you have a play around a bit with your fuel pump just remeber to mark things so you can revert to original settings
so inside fuel pump is a spring a washer and a diapham on the top is a little punch mark this shows basically the position of the needle mine was set at about 12 oclock standing from the wing is now after much playing about and trying differnt things is set at about 2 oclock and i have turned my smoke right down and have got rid of the washer altogether as this restricts the amount of fuel flow my top end is about 120 at moment and gets to 60 very fast with a climb from 80-95 on a very steep motorway hill passing every think result is empty tank quicker but if driven under normal cicumtances she very good but alot fun with extra touqe and power ofroading i get fuel burning when neede and not alot smoke hope this helps regards colin
Budgie:
This link will come in handy for explaining things if you want to play with the injector pump. :wink:
jnoshea:
--- Quote from: "muddyweb" ---James,
Just to add a bit of information..... The EGR valve mods won't have a huge effect on black smoke when you are accelerating hard off something like a roundabout.
This is (usually) a symptom of turbo lag...
On a diesel engine with all mechanical control like the 200 and most 300 tdi engines, the turbo is operated by the exhaust gas in the exhaust manifold. When you put your foot down hard, the injection pump throws a load more fuel into the system to make the engine go faster... because it is powered from the exhaust, and as such the boost is related to the engine revs, the turbo doesn't work any harder until the engine spins faster... so there is a slight delay in the boost increase as the engine comes up to speed. This is turbo lag... you often hear people talking about the turbo 'kicking-in'... this is when the boost pressure gets up enough to help the engine run faster and the power spirals upwards.
Now.. in the time between you hitting the pedal, and the turbo spinning up, there is an excess of fuel in the system... not all of this fuel is burnt in the cylinders because there isn't sufficient air from the inlet system to match the increased amount.... this shows up as a sooty cloud of smoke from the exhaust.
Hope that makes some sense !
There are some funky ways to negate turbo lag.. but they are all quite expensive ;-)
--- End quote ---
Thanks Tim, that makes perfect sense to me. Also explains why the car only smokes under exactly the conditions that you described. The rest of the time its fine after the initial startup. What causes the (smaller) plume of smoke when I first turn the engine over? Is it also unburnt diesel or is it oil?
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