Black smoke on gear change

Hi All, hoping someone can help me with some advice. I have a moment of black smoke just after each gear change when going up the gears. It clears up as soon as the revs pick up. Most noticeable on steep hills at low speeds, such as hilly urban areas where you never get the chance to get some speed up and maintain some momentum. The valve and fuel timing has been done, and the valve clearances set by a Landy specialist, but they are not sure what is causing it as "we don't see many 300tdis these days". The mechanic said there are two springs in the injection pump, one for cold and one for warm, or normal running. He said that the cold running spring can weaken with age, causing the fueling to be a bit rich at low revs, until the normal running spring comes in to play. That's how I remember it anyway, so I hope I have described what he said correctly. He also said it wasn't worth the expense of fixing it, as the engine is good in every other way. It's smooth and pulls fine. I would like it to run clean though, even though it drives well. Has anyone experienced this and got any advice please? Anything to do with injection pumps seems expensive, complicated and with plenty of opportunity for doing damage without specialist knowledge. Is it possible for a handy amature to replace these springs, and, do folks agree this sounds like the likely cause of the problem? Thanks very much for any help.

is this tdi new to you?

A puff of black smoke in a tdi on acceleration is normal

Might have been tweaked at some time in the past, std 200 and 300 inj pumps are a rare thing indeed.
They are dirty engines, but if in std state of tune should run visibly clear.

flat said:

is this tdi new to you?

A puff of black smoke in a tdi on acceleration is normal

Click to expand...

Hello Flat,
Yes, the Landy is new to me. It has done this since I bought it in July, so it hasn't come on suddenly. I should have mentioned it has done 180000 miles.

Hello Lynall,
So how would I return the injection pump to standard? Is this the thing about adjusting the advance and retard using drill bits as measuring tools, which I have read about? I would happily sacrifice a bit of power for a cleaner exhaust.

Are you able to get a video of the exhaust so
We can get an idea of it’s ‘normal amounts more excessive,

tbh if it passes the smoke test on the mot I wouldn’t worry at all

My TD5 used to smoke, giving it some right foot cleared it out

Our 200TDi Defender was the same, driven locally by an older gentleman, it smoked on hard acceleration, after a good few hard drives it soon cleared up

Have you tried running it with some injector cleaner added Likes of Millers
https://www.ebay.co.uk/itm/Millers-...155592&hash=item3dab41721d:g:OpYAAOSwBDdePAMW

Analogue Ben said:

Hello Lynall,
So how would I return the injection pump to standard? Is this the thing about adjusting the advance and retard using drill bits as measuring tools, which I have read about? I would happily sacrifice a bit of power for a cleaner exhaust.

Click to expand...

No, that is pump timing, and you can get a kit of pegs, you don't have to use drills.

I think what @lynall is saying is that the fuel delivery of the pump may have been turned up.

Are there any lockwires or paint seals on the screws on the pump? If so, it probably hasn't been messed with.

Turboman said:

No, that is pump timing, and you can get a kit of pegs, you don't have to use drills.

I think what @lynall is saying is that the fuel delivery of the pump may have been turned up.

Are there any lockwires or paint seals on the screws on the pump? If so, it probably hasn't been messed with.

Click to expand...

As Turboman says , quite possible it has been played with.
Things to look for :

On top of the pump there is a round circle , on a std pump this is fiilled with a metal annti tamper cap, on a pump that has been played with the cap will have been removed. If it has beeen removed you will see in the centre of the top in a recessed circle a t27 torx screw with a lock nut on it.

Also , chances are if this has been played with then the previous owner willl probably have fitted a "booost pin " to the inside of the pump , very easy to check , undo the 4 screws holding the top cover in place and remove the cover, inside will be a rubber diaphragm with a metal washer, ( check where the dot punch is on the metal washer for reference , it need s to be put back in the same place and check to see whether it has a std pin wichi is a conical offset pin or a single sloped pin ( this is a modified boost pin) .

Fianlly you can look at the back of the pump, near the stop solenoid sire you will see a 6mm hex head with a plastic ferrule anti tamper device cover, the ati tamper device is crush ring to control the postion of the max fuel screw.

Any of these changes will show that the fuel pump has been played with. you may find none or all have been tampered with, there is also a change that can be done to the star screw which the boost pin spring sits on, ( This affects the way the boost pin moves during the boost build up stage ) but this requires measuring as there are no ways to see if it has been modified from std position.

You may also find that the previous owner has upped the boost from the turbo pressure. But with no gauge there is no easy to know or confirm.IIRC you could count the threads on the wastegate bar but off the top of my head I cannot remember what a std wategate rod would show on thread count.


If it is offending you and you want to do something about it, and you can see the pump has been played with , I would start by winding the star wheel back ( ACW) 1 full turn and see if it affects it. This will apply more compression to the spring which will mean the boost pressure has to build slightly more before the same level of fueling is given.

Cheers

neilly said:

As Turboman says , quite possible it has been played with.
Things to look for :

On top of the pump there is a round circle , on a std pump this is fiilled with a metal annti tamper cap, on a pump that has been played with the cap will have been removed. If it has beeen removed you will see in the centre of the top in a recessed circle a t27 torx screw with a lock nut on it. View attachment 222904

Also , chances are if this has been played with then the previous owner willl probably have fitted a "booost pin " to the inside of the pump , very easy to check , undo the 4 screws holding the top cover in place and remove the cover, inside will be a rubber diaphragm with a metal washer, ( check where the dot punch is on the metal washer for reference , it need s to be put back in the same place and check to see whether it has a std pin wichi is a conical offset pin or a single sloped pin ( this is a modified boost pin) .

Fianlly you can look at the back of the pump, near the stop solenoid sire you will see a 6mm hex head with a plastic ferrule anti tamper device cover, the ati tamper device is crush ring to control the postion of the max fuel screw.
View attachment 222905
Any of these changes will show that the fuel pump has been played with. you may find none or all have been tampered with, there is also a change that can be done to the star screw which the boost pin spring sits on, ( This affects the way the boost pin moves during the boost build up stage ) but this requires measuring as there are no ways to see if it has been modified from std position.View attachment 222906

You may also find that the previous owner has upped the boost from the turbo pressure. But with no gauge there is no easy to know or confirm.IIRC you could count the threads on the wastegate bar but off the top of my head I cannot remember what a std wategate rod would show on thread count.


If it is offending you and you want to do something about it, and you can see the pump has been played with , I would start by winding the star wheel back ( ACW) 1 full turn and see if it affects it. This will apply more compression to the spring which will mean the boost pressure has to build slightly more before the same level of fueling is given.

Cheers

Click to expand...

Excellent. I wasn't sure what Bosch pumps have, I have always had CAV.

Analogue Ben said:

Hello Lynall,
So how would I return the injection pump to standard? Is this the thing about adjusting the advance and retard using drill bits as measuring tools, which I have read about? I would happily sacrifice a bit of power for a cleaner exhaust.

Click to expand...

It depends which bit has been adjusted if at all.
Mine is not std, and the only time I see smoke is at night with a car behine me.

This may help

Thanks for all the replies everyone. I am new to Landyzone but really glad I joined as there is so much information here, and generous people sharing their time and experience.
To respond to some of the suggestions; I've not had a chance to film the exhaust yet, but it is just black smoke on acceleration most noticeably after a gear change, I have used loads of fuel system/injector cleaner with little noticeable difference, the Landy doesn't get driven very hard but has had a couple of longish 60 to 70 mph runs from West Cumbria to Yorkshire, again not made any difference.
Thanks for all the info on pumps. I will take a look this week to see if it has been fiddled with as described.
It is a shame about the smoke as it drives nicely and feels and sounds like a good engine otherwise.
I will report back on how I get on with following all your guidance. Cheers.

Thought I'd add an update to this thread, as things moved on after the last posts. The problems seemed to be a combination of things. The turbo was worn out, so that was replaced, which improved things, but then the problem of smoke returned combined with a drastic loss of power. By this time everything else had been checked and eliminated so the only thing left was the injector pump. Had a choice of a Chinese copy or getting the Bosch pump rebuilt. Went for the rebuild and very happy that I did. Cost about £350. The Landy is now a very reliable daily driver. It basically needed some TLC and proper money spending on it, after being used as a low annual milage/low annual investment vehicle by previous owners.