thebiglad
Well-Known Member
got a 300tdi it smokes at low revsaround town not on a run! changed glow plugs/injectors full service, knocking/tapping noise dose anyone know what it is?
Before giving you an answer, got a couple of questions:
Is it a Disco, if yes, what year and what gearbox - man or auto?
Have you checked the air filter? If in any doubt at all, put new one in. Filter sets for a Disco Tdi 300 are only about £7 from these people:
www.paddock-spares.com
Have you been able to locate the source of the tapping? Is it the lift pump - if yes, £15 from the above place.
PASTMASTER
Well-Known Member
If you can't find a fix, both biodiesel and BP Ultimate are said to reduce smoking.
thebiglad
Well-Known Member
So it's a Disco, Tdi 300, manual gearbox. That's fine, now we are getting somewhere.
It's unlikely to have EDC (electronic diesel control) so that makes it more straightforward.
Do you know what the EGR valve is? and whether or not yours is blocked off. These can cause the smoke and lack of low end power you are describing.
What colour is the smoke? If it's black, it's likely to be over-fuelling due to insufficient air getting in - bad air filter, turbo pipes delaminating or intercooler partially blocked.
If It's blue, that's burning oil and is often worn valve stems or a worn-out turbo.
If it's white smoke, it's either steam indicating a potential blown head gasket or if it is smoke it's over-fuelling to do bad pump timing.
Most people have black smoke problems so I would start looking at the condition of all the rubber pipes between the air filter box and the inlet manifold. Check them for leaks and delamination ON THE INSIDE.
You say this happens at low revs, this could also be due to you giving it too much throttle for the revs. For example, if these cars are driven at 30mph and you floor the accelerator, you will get smoke because the engine just can't burn enough of it at such low revs.
For your info, I normally change up at about 2500rpm.
Hope that helps,
Dave
