Yet another smokey 200tdi...

[jackbw28]

Hi all,

I know there is lots of info on this there but this is a little different and wondering if anybody has a bright idea to this one...

I have relatively recently moved back to Kenya with my 200tdi Defender... I now live at 6500ft and my 200tdi has started to chuck out a considerable amount of black smoke.

The engine is a recon unit, as is the pump, injectors and turbo - all done in UK and set/calibrated to standard settings. I set the timing and pretty sure got it bang on.

I have the usual puff on startup, but then I get a hell of a lot at low RPM on load (pulling away etc). Once the turbo spools up the smoke is less, but still more than I think it should be.

I did think it was altitude; less oxygen and the same quantity of fuel thus a higher ratio of fuel and incomplete combustion. However I think there is more at play given the amount of smoke.

The fuel filter is new (though 'sedimenter' not checked in years) no fuel line leaks visible. I assume this to be a fuelling issue given the colour of the smoke and no/little oil consumption/contamination and only having 6000km or so on the engine.

Engine seems to run well otherwise, though 'could' be low on power at the bottom end (before turbo kicks in) but this could just be how it is. I do also get relatively high EGT - 800 degress (before turbo) on a long hill under load.

At low altitude (just been down to the coast at 0ft) the amount of smoke does decrease, though not to what it was just after the re-build.

Fuel quality pretty good these days out here if you use the right petrol station as I do.

So, any ideas as to what could be causing this?
Finally, regarding the bosch pump - does it compensate for atmospheric pressure? It can detect the pressure from the turbo when it spools up and alter fuelling accordingly so I'd expect it to detect the change in atmospheric pressure that may occur at altitude... Or does it simply detect the change in pressure relative to atmospheric??

Thank very much to any ideas anybody may have,

Jack

[Mo Murphy]

It's your altitude Jack, mine does the same in the Alps and the Pyrenees, unless you've been playing with the injection pump. Black smoke is unburnt fuel, I'd worry if it was blue smoke.

Mo

[Snagger]

The boost diaphragm has atmospheric pressure on its underside. St high altitude, this pressure would drop and it would be easier to turbo boost pressure to overcome and add more fuel, giving black smoke, but that should only happen once the turbo is spinning up, not at low rpm. It sounds like you need to retard the injection timing a little.

[jackbw28]

Thanks guys,

Injection pump has been reconditioned by a bosch agent in the UK - should be to standard settings/calibration. I suppose it could be altitude, but I just think there is a bit more to it, due to the sheer volume of black smoke before the turbo kicks in.

She is also pretty gutless until the turbo kicks in around 2000 RPM. I'm not 100% sure if this is normal or not though, can't clearly remember how she went before the engine rebuild but I don't 'remember' this issue.

For example, going up a reasonably steep hill on the way home from work I HAVE to maintain an RPM greater than 2000 or the engine grumbles as if its overloaded and going to stall. This means I must down-shift and keep the revs quite high before up-shifting again, otherwise when I up-shift the revs will be under 2K and it wont go. Generally I have to drop down to 3rd when I reckon 4th should be suitable to maintain a half decent speed and allowing up-shift again. I need to get up to about 45mph in 3rd with the engine screaming before changing to 4th. Vehicle is a 110 and this happens un-laden. When laden its worse.

I'm beginning to think injectors... I had a good look this morning and found some soot/oil around the recess where the injectors fit into the head. So they may not be sealing properly, though I cannot detect any gas escaping. The much could just be due to other leaks and carp falling in there though.
Also, when I initially fitted these (recon) injectors cyl. 2 'injector' did leak and spray a load of oily muck over the bonnet. I simply tightened the clamp nut and it stopped but I had torqued the nut to the specified 25Nm initially.

What do you reckon?

Thanks for the description of how the pump alters fuelling with regards to the boost - interesting. Now retarding injection timing is interesting, that is where you rotate the pump body slightly? I can't remember how I set this initially tbh, I'll do a bit of research into it. Thanks.

[vulcan bomber]

The boost diaphragm has atmospheric pressure on its underside. St high altitude, this pressure would drop and it would be easier to turbo boost pressure to overcome and add more fuel, giving black smoke, but that should only happen once the turbo is spinning up, not at low rpm. It sounds like you need to retard the injection timing a little.

the diaphram is controlled by spring pressure not atmospheric.

[Snagger]

The resistance against the boost pressure is by a spring, but that spring and the plunger the diaphragm operates sits in a void vented to atmosphere. If it can't vent, then any displacement in the diaphragm will pressurise the void, helping the spring and reducing boost response. Equally, a change in altitude will affect boost response if the void breather is blocked because an increase in altitude will reduce the pressure from the turbo, but the trapped pressure below the diaphragm will assist the spring. You may think that won't happen because the turbo will spin faster to provide the boost setting on the waste gate actuator rod, but remember that the actuator senses boost pressure on one side and atmospheric on the other, so the boost from the turbo may be the same, but overall output pressure is lower. Conversely, an engine tuned for high altitude will gain pressure for a given boost from the turbo at lower altitude and a bocked lower void breather will increase fuelling because of the increased atmospheric pressure plus any boost acting on the diaphragm against the spring.

[jackbw28]

Thank you for the description of the diaphragm operation. And, judging by that, I don't only have an altitude issue as my pump should compensate for altitude until the boost picks up. My smoke is worst off boost/low rpm.

Today I managed to prove to my-self two injectors were leaking, this issue was solved by replacing the copper washers. My head was pretty dirty so I cleaned it up and went for a 10 minute drive and found oily black deposits leaking from injector 1 and 3. No. 2 was also leaking but not as obvious, only no. 4 was clean.

Despite fixing this I still have the smoke issue. Engine runs a little better, but not as much of an improvement as I was hoping for!
I do hope oil is not the cause!

I am now considering 'playing with the pump' to tackle the smoke issue, but ideally I'd like to know exactly what is happening... I do get high EGTs (even in the UK just after the work was done). I let it go to 800 C then back off on the throttle if it wants to go higher, and it will if I keep the power down on a long hill. I understand this is a bit high for this engine and the result of over-fuelling.

Snagger, I'm very interested in your idea of retarding the timing a tad and think it preferable to altering pump settings but can you please give more info on why this would help? Come to think of it, I could have set it slightly out initially. I simply used a 9mm (i think) rod in the pump cog hole and then tightened it all up - however there was some play around the 9mm bar, I didnt think too much of it.
Does anybody have any good links to the procedure of retarding the timing?

Thanks again.

[Snagger]

The main part of the injection pump is not sensitive to altitude or air pressure, just to engine rpm and throttle demand. SInce it would have originally been calibrated for sea level use, it will be throwing in fuel to suit sea level air intake. That would create a noticeable though not enormous amount of smoke. If you have any kind of restriction in the intake, then the air consumption would be even further reduced until the turbo spins up enough to compensate, causing thick black smoke until on boost.

Check the induction system for blockages and drain and flush the intercooler, replace the air filter. You may also need to recalibrate the injection pump by turning the baseline fuel down a tad - it's the screw on the rear face of the pump below the fuel solenoid and the leak-off hose connection. Turn it anti clockwise to reduce fuel, but note the original position and try no more than a 45 degree turn at a time. Make a written tally of the number of adjustments and use Tipex or nail polish to mark the original orientation of the screw before you start so that you can reset it to factory settings if it doesn't help.

[discomikey]

wish my head was that clean!!

[steve b]

check your flexible pipework between the turbo and inlet for internal delamination too , when they do it acts as a flap valve and

destroys flow

let us know how it goes

cheers

Steveb

[jackbw28]

Thanks for your advice Snagger.

Driving to and from work today and she is definitely going better with the injectors not leaking! Smoke is not too bad under high RPM with the turbo up and running. Its still pretty bad at the bottom end though.

So, you reckon play with the pump first and leave the timing alone?

I will try the smoke screw, but also wondering if there is a way to reduce fuelling only before the turbo kicks in and not across the board. Perhaps something around the boost diaphragm? I will try to get and read a bosch VE manual to fully understand this.
I still don't want to loose power, I need as much as I can get. As much as I love this engine I do wonder if I should have attempted to fit a Td5 when I rebuilt the vehicle.

Haha, the head is clean, as its all basically new/reconditioned - I'm trying to keep it that way, not an easy task - rocker cover gasket now leaking...

Thanks Steve, All the pipework and air-filter was new 6000km ago, I even put a new air-filter in last week as the previous 'new' one was already all clogged up from 2000Km of dirt roads. The intake is still in an awful position and just sucks dust, yet to fit a snorkel.

Jack

[discomikey]

you can change the pre boost fuelling, the on boost fuelling and the full range fuelling on these pumps its relatively easy, only ensure to mark out the positions of everything and count turns etc. most importantly only play with one setting at once. this means that if you have made a mess of things you can still revert back to what it is now.

theres a guide here.. http://www.landroverweb.com/Pdf-files/Tuning_Land_Rover_Tdi_engines_Rev_2.pdf

[Snagger]

That's a good guide, but it doesn't mention the baseline fuelling adjustment screw on the rear face.

I would try retarding the injection a tiny amount first and seeing if that reduces the black smoke without power reduction. If you get grey smoke instead, then it's still delivering too much fuel but is too retarded. In that case, I'd try that fuelling screw at the back, no more than 45 degrees at a time.

[discomikey]

i was sure it mentioned that, because it mentioned even 1/4 turn making large EGT changes.

but anyway IMO thats the one you touch last anyway.

[jackbw28]

Thanks guys,

Sorry for the late reply, haven't had much time this week.

That is indeed a very good guide thanks very much for the link.
I think I will do as snagger says and retard the timing slightly first before moving onto the pump.
If/when it gets to the pump I will probably adjust the off-boost fuelling to start and go from there. The guide does mention the baseline fuelling adjustment on the rear face, albeit briefly at the end of the article.
I need to double-check but the article suggests it's pretty easy to adjust off-boost fuelling, so much so I am tempted to just try that before the timing adjustment as it is quicker...

I'll let you all know how it goes when I get about to making the changes.

[jackbw28]

Ok, a bit late I know, but I have finally got round to doing some tweaking. Sadly however I'm not too happy with the way its gone and would appreciate some advice!

First I retarded the timing a little and left the pump alone.
The engine was certainly quieter and revved up quicker - however no reduction in smoke or EGT (as expected). also a slight decrease in power. I did try retarding the injection timing further but just got white smoke so backed off.

I then decided to go the other way and advanced the timing a tad. This had better results with smoke slightly down and EGT slightly down. But only very slightly.

I then got a bit carried away and advanced it further! Now I thought I could notice more power on the highway but noise levels were up. Smoke still excessive (across the whole RPM range) and EGT high on hills.

None of the above really cured my lack of mid-range power 1500-200 RPM.

I then turned the base-line fuelling down (anticlockwise) by 3/4 a turn (in increments). Smoke and EGT now acceptable but power down!
When I first drove the car like this I thought it was pretty good - seemed so on the highway. However on 'A' roads the power is certainly worse than before.

I'm thinking this is to do with timing as I still get light black smoke throughout the RPM range so don't think fuel is being restricted. I didn't play with the diaphragm as I get plenty of smoke in the mid-range and simply adjusted the base-line fuelling such that I had a light mist of black smoke on full throttle. I still get black smoke throughout with this setting.

Any ideas?

I plan on putting the timing back to the stock setting and observing what happens..

Finally ... injector sealing. This could be the issue. I did change the washers after the obvious leaking photographed above. I did this before doing anything else - and though still smokey I had plenty of power.

However I can now see the familiar trail of oil from No. 3 injector yet again! I'm just not 100% convinced its the injector or oil leaking from the rocker cover gasket...

My old disco 200 never had issues with the injectors not sealing properly.. I will probably fit new washers yet again this week.

Thanks,

Jack