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smoke when giving it welly

1020 Views 19 Replies 8 Participants Last post by  mondeotdci130
hi all.
im after some advice again.
my beast ticks over fine,starts fine, but when i give it some welly (not often) :laugh: i get quite a bit of black (i think) smoke . i have noticed the fuel consumption is not as good. i have cleaned the inlet manifold and egr (500 miles ago) it was real bad :shocked: . i only use shell diesel. it had a full service 2k ago.its only got 43k on the clock. im now stumped? any ideas guys/girls.
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I'd start by checking the intercooler/EGR/turbo rubber piping for splits.
try uncoupling the EGR vacuum pipe, maybe the EGR is opening to soon
all pipes checked and seem ok.
i will try disconecting the egr valve . will it still be ok to give it a litte whilst of???
I have exactly the same problem and also poor performance to go with it. Feels like driving without a turbo. I have disconnected the egr vacuum and initially it was great but it's got worse again. Think my egr is stuck open.

I keep wondering about a split boost problem but can't hear any wooshing noises.
Driving a diesel gently most of the time will be partly to blame for the smoke when booting it.

Diesels pass MOTs easier if given a good blast before the MOT. Wonder how much soot collects in the exhaust system?
hi all ,just to let you all no that i have checked everything today and all seems fine, so im still none the wiser.this only happens when i really boot it, which to be honest isnt that often but now its doing it its bugging me. has anybody got any other sugestions???? thanks in advance.
PURPLE_2L_LX said:
Driving a diesel gently most of the time will be partly to blame for the smoke when booting it.

Diesels pass MOTs easier if given a good blast before the MOT. Wonder how much soot collects in the exhaust system?
dunno but looking at my EGR id guess we havent quite got clean diesels just yet

if that reduced airflow by 10%-15% what power/torque was i down, wont be 100% sure till ive done the manifold

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nice :eek13: . mine was twice as bad as that and my manifold wernt that good either :shocked: . mine did run alot better when done tho :content: think im gona try some millers.
on the advice of the mot tester i had to take mine for a 3 or 4 mile blast , open road 3rd gear at about 4000 rpm to clear the shite out before it would pass the emissions.smoked like a good un at first but then cleared.sailed thru the emissions after that and felt more responsive.
1.long periods of gentle driving means the EGR never opens, all the cack in the system backs up, welly then opens the EGR hence smoke

2. the same steady driving soots up the exhaust, the loose stuff breaks away under welly

check yr filter, clean the MAF and check your EGR/manifold

cant help can it....

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It is very normal for diesels to smoke under a heavy foot like said above when driven round town etc the soot builds up and a good blast soon blows it away you will prob find that if you do that two or three times on a good piece of rd you will cure your smoke millers or like are a good bet two my egr was compleatly black i cleaned out both and started using millers i went to clean it again after same amount of milage and it was clean :)
what worries me about the EGR crud was that it was BOTH sides of the incoming port for exhaust gases, if the valve only opens on "welly" wouldnt you expect to only find the buildup on the side of the bore from the incoming port as the intercooler (blown) air should force everything towards the inlet, so how come it was evenly crudded BOTH sides of the side/incoming port?....

in other words the crud allowed into the EGR on "welly" should have gone one way (towards the inlet) but was BOTH sides of the port in the bore of the EGR
the EGR opens at idle and low rpm, when combustion temps will be high with excess air to fuel.
the EGR valve recirculates exhaust gas to dilute fresh oxygen to richen the fuel/air mix, so combustion temps do not rise above 1200 degrees, this is were Nox is created, so keepinmg below this temp reduces nox. all this is for emmissions and not efficiency.
a side effect of exhaust gas recirculation is soot, so a DPf is required.
removing/blanking an EGRvalve, will reduce soot, improve Mpg, and increase reliability of an engine, as its not taking in extra crud and shit.
that still doesnt explain EGR crud BOTH sides of the incoming side port does it

i get "smoke" in one particular place, i slow down to 15mph to make a hard left turn and then have to accelereate up a moderate hill, as i throttle up i can see (in my NS mirror) black smoke, not at any heavy throttle or great revs

BTW, there NEEDNT be soot out of a diesel engine at all, if the pump is turned down, but that limits horsepower....
There are trade offs however. Adding EGR to a diesel reduces the specific heat ratio of the combustion gases in the power stroke. This reduces the amount of power that can be extracted by the piston. EGR also tends to reduce the amount of fuel burned in the power stroke. This is evident by the increase in particulate emissions that corresponds to an increase in EGR. Particulate matter (mainly carbon) that is not burned in the power stroke is wasted energy. Stricter regulations on particulate matter(PM) call for further emission controls to be introduced to compensate for the PM emissions introduced by EGR. The most common is particulate filters in the exhaust system that result in reduced fuel efficiency. Since EGR increases the amount of PM that must be dealt with and reduces the exhaust gas temperatures and available oxygen these filters need to function properly to burn off soot,
the build up in EGRs pipes and head, is the oil vapour and soot mixing, you will always get oil vapour, from the crankcase breather, and sometimes small amount from turbo(normal) as soot is a byproduct from EGR recirculation in the exhaust and a small amount of oil vapour can come out of exhaust at some points(specially if you have bad oil or wrong oil) it mixes at all points, also when EGR starts to play up, there will be times when it is still open when it shouldnt be and you will get turbulance at the EGR, so you get a build up at all points around there, but if you look further down you wont have any carbon in boost pipe or intercooler, just oil.
the crud stopped at the rubber hose, in that was only some wet black stuff, and not much (vehicles done 75k remember, doubt the egrs been off b4))
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