300 TDi Black smoke !

Hi
I have 2 black smoke problems on 1994 ( No EGR) 300 tdi Disco .
One on start up it kicks out a massive cloud of black smoke ! I know they do this , my Defender 200tdi and my sons 300tdi Defender do a bit but no where near as bad as this !!!

Also black smoke when you put your foot down .

I have changed injector tips for some new Bearmachs and it was worse so cleaned and checked and put old ones back in . Changed diesel, air filter and cleaned sediment filter , cleaned inter cooler which was already clean , new silicon hoses , set tappet clearances , checked timing with lock pins on fly wheel , checked injection pump hasn’t been tampered with ( boost pin turned )

Starts on the button , runs well any thoughts as I’m proper stumped?

Cheers

Vehicle new to me so don’t know any other info . My daughter that has just passed her test is going to be using it for university so just trying to save her some embarrassing moments

Has the inj pump max fuel screw been wound in? it is the M6 bolt with a 6mm spanner head, should have an anti tamper seal fitted it it has not been touched.

Have you tested the injectors for spray pattern?

Does it go well, ie rev out inn each gear, then get a little flatter power wise in 4th and fifth gear top end?

I know it sounds daft, but have you serviced it? New air filter, new fuel filter? Could just be the mix is out of whack.

I also do advocate redex diesel cleaner, a tank of that through my old 90 cleaned up the smoke a treat.

Failing all that, I'd suggest checking the cylinder compression to at least rule out a valve issue.

I hope your overfuelling issue is simpler than mine is turning out to be

Will watch your thread for the outcome - good luck.

lynall said:

Has the inj pump max fuel screw been wound in? it is the M6 bolt with a 6mm spanner head, should have an anti tamper seal fitted it it has not been touched.

Have you tested the injectors for spray pattern?

Does it go well, ie rev out inn each gear, then get a little flatter power wise in 4th and fifth gear top end?

Click to expand...

Thanks for your reply .

Max fuel screw ( smoke screw ) not been touched as it still has its anti tamper coller !

Living in rural France I have only checked the injector spray pattern with a very basic home made set up . Looks good and no holes blocked .

Yes ! Will rev to the limit in every gear so not a power problem . To be honest with you the black smoke when running is not too bad ( went through it’s local emissions test no problem ) .The worst of the 2 is when it blows out a cloud of black smoke (hot or cold ) on start up !’

Obi_110 said:

I know it sounds daft, but have you serviced it? New air filter, new fuel filter? Could just be the mix is out of whack.

I also do advocate redex diesel cleaner, a tank of that through my old 90 cleaned up the smoke a treat.

Failing all that, I'd suggest checking the cylinder compression to at least rule out a valve issue.

I hope your overfuelling issue is simpler than mine is turning out to be

Will watch your thread for the outcome - good luck.

Click to expand...

Thanks for your input ;-)

Yes fully serviced all oils and filters !
It’s had a few “Italian tunes” and apparently the cylinder head and valves are new so I don’t think it’s a valve and when you take the oil filler plug off there is absolutely no block pressure .

I do think it’s not as sweet noise wise compared to my 200tdi and my sons 300 tdi ??

I will defo try some redex ! Got to be worth a try ;-)

Black smoke = too much fuel

There are several causes for this.
Not enough air (blocked filters etc) [It's not that as you've replaced the filters]
Blocked jets/injectors.
FiP.
a) Delivery (max fuel) screw
b) Pin position (relative to main injector valve)
c) Vacuum diaphram spring height
d) Vacuum diaphram spring preload/tension (starwheel)
d) Worn internals

Have you tried unscrewing the max fuel screw (by 1/4 of a turn) ?

It does sound like an adjustment issue.
Here is an excellent document.

Jason2 said:

Thanks for your reply .

Max fuel screw ( smoke screw ) not been touched as it still has its anti tamper coller !

Living in rural France I have only checked the injector spray pattern with a very basic home made set up . Looks good and no holes blocked .

Yes ! Will rev to the limit in every gear so not a power problem . To be honest with you the black smoke when running is not too bad ( went through it’s local emissions test no problem ) .The worst of the 2 is when it blows out a cloud of black smoke (hot or cold ) on start up !’

Click to expand...

Iirc the 300 bosch ve pump had a spring loaded widget you could see externally, think it was engine side of the inj pump, always worth checking that is free, otherwise I reckon you could be into inj pump and injector service.

Different 300 versions had different inj pump timing, (not the timing pins but the actual amount of lift at a certain point) only knatts cock difference, and again I doubt that is your issue, but got to be worth checking, need a dti gauge and adaptor for the pump, sounds scary? it is not see youtube for vids on how to do it.

Was the fuel pin the original or an after market tuning one? easy to tell, oe is like an upside down ice cream cone, tuning one just had a bit machined out of it, and causes all sorts of smoke issues.
Did you make sure the small pin at the bottom of the hole was free to move in and out? as they like to seize.

Taking it back to basics and assuming it really is black smoke as in unburnt diesel and not something else causing smoke. It comes down to too little air or too much fuel. Or a combo.

Check the intake hoses aren't collapsing and that the turbo is making boost. If so, then it may well have been modded at some point. Maybe a boost pin or similar.

Thank you all for your helpful information!
Much appreciated!
I will let you know how I get on ;-)

Still not sorted this !

Checked everything so was wondering if the injection pump is in the right position and the flywheel when I check the timing could it be the cam sprocket that is out 1 tooth either way ? Obviously can't check with out stripping down and if so I will change cambelt water pump at the same time !

Or although the injection pump is spot on with a 9mm drill bit when I check timing would it be worth trying to advance or retard it obviously marking original position before hand ?

Starts brilliantly but smokes, lack of power and compared to my sons 300tdi Defender makes a lot more noise !

Thanks in advance

On my D1 300 tdi I can remove the idler pulley for the aircon and the hole lines up perfectly with the 3 bolts that hold the belt sprocket to the injector pump

Not sure of the exact amount of movement you can get but I have used that "slack" to get the timing set for more power at say 1500 rpm vs 3000 rpm

That also changed the noise level substantially between the diff rev range

Jason2 said:

Still not sorted this !
<snip>

Starts brilliantly but smokes, lack of power and compared to my sons 300tdi Defender makes a lot more noise !

Click to expand...

My last 300tdi was like your sons, quiet, picked up well, drove like a car, loads of power compared to my (newer) new one.
I checked everything.
Fitting a new timing belt helped (the PO had fitted a Britpart and had a loose belt tensioner pulley).
The real leap was to send my pump off to Diesel Bob for a full refurb.

My Defender is 'almost' as good now, still a little more noise (rattly and clanky) but vastly improved on get up and go. No longer a 75 year old ex hobby footballer but still not quite a reincarnated 30 year old 1/2 marathon runner.

Sorted !

I took the injection pump timing cover off , Grabbed a 22mm socket and a 10mm socket and found a quite stretch of road . And then just kept slowly adjusting the timing slackening the 10mm bolts and turning the 22mm centre bolt , locking 10mm bolts up and driving until it stopped smoking ! If you go too far it smokes white .

Thank you all for help