200tdi. Smoke screw vs Full load screw?

Can someone tell me what the difference is between these two?

Landy failed on emissions (among many other things). I've stuck some redex in the tank and given it a good run in low gears (on private land of course) so hopefully that will clean it up a bit. I have been reading for a while about tweaking the pump but can't work out which of these I should adjust to reduce smoke at higher throttle positions.

It's actually a 200di in a series without the turbo so I don't think the diaphragm and star nut will do anything?

From what I understand the emissions should be tested using the criteria from the previous engine so there must be something seriously wrong if its failing compared with the series engine specs

Yeah it doesn't actually seem THAT bad to me but I suppose it's all subjective. There is quite a thick cloud at the top end. The garage is literally 50m along the road from my house so I'd have no excuse if I got caught ragging it round the back roads. Hopefully the redex will work its magic. I got it fully warmed up today so will have another try tomorrow and see what it's looking like.

If it is the fuel pump then look at the max fuel screw on back / side facing towards the bulkhead. If it still has the tack weld on it then it hasn't been touched. Mine has been tweaked and passed MOT. The smoke screw to my knowelege is the one on the top under the little tin cap. This is the low boost / off boost fuel screw, which will cause lots of black smoke on idle or when pulling away if not correct.

Make sure turbo seal int on way out (excessive oil in turbo / hoses), air filter clean, oil ok etc.

D90mitch said:

Make sure turbo seal int on way out (excessive oil in turbo / hoses), air filter clean, oil ok etc.

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He's got a 200 with no turbo

Star wheel won't make any difference but smoke screw on top of pump will as it sets what part of the fuel pin that the needle will sit on and therefore low speed fuel delivery rate. The star wheel is there to adjust the rate of fuel increase as the turbo boost increases but as you don't have a turbo it wont have any effect.

get the numbers from the guy. sounds odd it failed. it's like 2.5-3.0 for a s3 isn't it. and a visible check for older.

It's a 1971 so I think just a visual check? That's what he did anyway.

Kwakerman said:

Star wheel won't make any difference but smoke screw on top of pump will as it sets what part of the fuel pin that the needle will sit on and therefore low speed fuel delivery rate. The star wheel is there to adjust the rate of fuel increase as the turbo boost increases but as you don't have a turbo it wont have any effect.

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So the smoke screw sets low speed fuel delivery and the full load screw (on the back of the pump) sets high speed?

CalumM said:

It's a 1971 so I think just a visual check? That's what he did anyway.



So the smoke screw sets low speed fuel delivery and the full load screw (on the back of the pump) sets high speed?

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so he failed on a visible check which is just to see it's not smoking like crazy..

how bad is it? it must be well out of whack to fail imo

I'll take a video of it later. There is definitely black smoke at high throttle but to me it looks like normal Land Rover smoke.

I have a 200di fitted in mine , when 1st using used to smoke so I initially adjusted the nut on the top of diaphragm with little success I then tried rotating the diaphragm so the pin off it allowed the lower pin to move further back this cured my smoke problem.
the pin hole in diaphragm on mine originally 1pm now set 9am minimum set point.

CalumM said:

It's a 1971 so I think just a visual check? That's what he did anyway.



So the smoke screw sets low speed fuel delivery and the full load screw (on the back of the pump) sets high speed?

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Basically yes for your installation, just be wary about adjusting the full load screw as that can raise your exhaust gas temp. Normally it would be the turbo which gets damaged by high temps but as you don't have one its not so much of a worry

Bit of an update. I let it idle for a while then revved it really hard for a bit and after that it seemed to get a bit better and it hadn't even really warmed up yet. I might take it for another drive (again on private land, of course) to try and get more of the redex through the injectors. Is it possible that a small amount of oil could pool somewhere then get burned off when I first start the engine?

The MOT place is literally a 100m away from my driveway so when I dropped it off last time I'd barely even touched the throttle. Maybe before I drop if off next time I'll just rev the tits off it and try and get him to check the smoke straight away when I get there instead of letting it cool down.

Kwakerman said:

Basically yes for your installation, just be wary about adjusting the full load screw as that can raise your exhaust gas temp. Normally it would be the turbo which gets damaged by high temps but as you don't have one its not so much of a worry

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Ok cheers I might give it a small adjustment and see if it makes any difference. Done carbs before but never adjusted and injection pump.

maybe take it to another mot place next time. guy sounds very harsh.

Update for you. It passed the retest!

For the smoke I changed the air filter, gave it an italian tune up and put a new fuel filter full of redex on. The guy adjusted the pump a bit at the mot and I'm sure it runs a lot smoother than it used to. I had tried adjusting the pump myself but it didn't seem to make a difference one way or the other.

The exhaust is in a bad way. I put some filler stuff on to get through the mot but it won't last long. I think I will go for a stainless one before the next mot.

Look at the state of the old air filter compared to the new one.

Try running some new veg oil in the fuel tank, about 5litres at 50% to diesel, you'll need to change the fuel filter a few times as it'll clean all the pipes through...

check the valve clearences as well ...