Black Smoke on Hard Acceleration

[philhunt]

Had a full width intercooler fitted about 9 months ago which made a huge difference to performance on my 300 tdi particularly at the bottom end. When it was fitted the fuelling was adjusted and I was told that there was a fine line between achieving optimum performance and better performance but with more smoke!

In the last month or so, I've started to get a lot more smoke on hard acceleration. When I ease off the throttle, the smoke level goes back to normal. My fuel filter has been replaced since the problem started and I have a K&N filter which has been in for only 5000 miles. I've run some fuel system/injector cleaner through the tank and there's been no improvement.

I've an MOT due next month and it would be difficult for me to get back to the firm who fitted the intercooler in the next couple of weeks. I assume that I can make some minor adjustments to the fuelling given the right guidance and photos/diagrams from Forum members so hopefully some of you experts will come up trumps for me like you usually do!

[extreme90]

who fitted the intercooler
and exactly what part of the pump did they make adjustments to ?
it sounds to me like the full load screw( smoke screw) need's backing off 1/4 of a turn
dan

[philhunt]

who fitted the intercooler
and exactly what part of the pump did they make adjustments to ?
it sounds to me like the full load screw( smoke screw) need's backing off 1/4 of a turn
dan

Scorpion did the intercooler - not sure which part/s of the pump they adjusted.

Is the full load screw (smoke screw) the one under the diaphram?

[bilge rat]

prob back off the diaphram about 1/8 -1/4 0f a turn too. mark it first you can always set it back then. alan......

[treeman]

not to sure if this would work but wouldnt fitting a fuel pressure regulator save messin about with the fuel pump?? just fit in the fuel line and wind it down for the mot, this is what i do on my corsa because i have took the cat off, it doesnt run good at all but its way under the emissions :-)

[philhunt]

not to sure if this would work but wouldnt fitting a fuel pressure regulator save messin about with the fuel pump?? just fit in the fuel line and wind it down for the mot, this is what i do on my corsa because i have took the cat off, it doesnt run good at all but its way under the emissions :-)

An interesting thought. Where would I get one from and where in the fuel line would I fit it? Anyone else using one?

[Xtremeteam]

not to sure if this would work but wouldnt fitting a fuel pressure regulator save messin about with the fuel pump?? just fit in the fuel line and wind it down for the mot, this is what i do on my corsa because i have took the cat off, it doesnt run good at all but its way under the emissions :-)

its a diesel

that wont work as the supply from the lift pump to the inj pump is low pressure

[Niel]

In the last month or so, I've started to get a lot more smoke on hard acceleration. When I ease off the throttle, the smoke level goes back to normal. My fuel filter has been replaced since the problem started and I have a K&N filter which has been in for only 5000 miles. I've run some fuel system/injector cleaner through the tank and there's been no improvement.

Check the air-filter and that no hoses are collapsing internally limiting air flow...

[philhunt]

In the last month or so, I've started to get a lot more smoke on hard acceleration. When I ease off the throttle, the smoke level goes back to normal. My fuel filter has been replaced since the problem started and I have a K&N filter which has been in for only 5000 miles. I've run some fuel system/injector cleaner through the tank and there's been no improvement.

Check the air-filter and that no hoses are collapsing internally limiting air flow...

The air filter's fine (see my original post) - all of the rubber hoses were replaced with silicon hoses when the intercooler was fitted

[Niel]

Check the air-filter and that no hoses are collapsing internally limiting air flow...

The air filter's fine (see my original post) - all of the rubber hoses were replaced with silicon hoses when the intercooler was fitted

You've actually looked at the filter? BTDT!!!!

[Ja1983]

to be honest its more an issue of the chemicals in the smoke, over the density of smoke... mine regularly poofs up enough to cover the tailgaiter behind under hard acceleration, but you have to remeber that this is while the engine is under load.... for the MOT ?(IIRC) they rev it stationary, thus less will come through anyway... i`m also thinking that the nastys in the exhaust are reduced  when you run bio-dev...

the off boost fuel adustment is controlled by the little * drive behind the dust cover



"First off is to adjust the smoke screw, this apparently controls off boost fuelling and can be accessed by removing a small metal 'dust' cap, it is held in place by a 13mm locknut and the screw has a Torx head, I slackened the lock nut and held the nut whilst I wound the screw in half a turn... Has it helped?????
Well I run on bio veg oil and when cold the engine has always hunted (revs rise n fall), turning this has virtually eliminated that so Im more than happy, could've turned it more as it still doesnt smoke but I will run a while first..."

....the above is the guide to INCREASE the fuelling, so i would do the reverse of that...

have you disconnected the EGR pipe? - if so, reconnecting will help.

maybe pop down the MOT station before hand and have a quiet word... they may well say "yeah, its a diesel.. we did one t`other week twice as bad and it flew through"

..or they could also say "dont you dare bring that thing down here!"

this little bit of insight could well saver you getting messy and having to tinker afterwards to rectify the fuelling...not that you would of course, as this would then invalidate the emissions test that was carried out on the MOT (you know what i mean ;) )