Discovery 2 V8 2001 emissions test

Hi all,
I had Disco checked recently for emissions.I had put a big bottle of Redex pre Mot liquid in the fuel tank and hoped it would clean up my emissions.
Been using Redex for 50 years,never been sure if it doe any good.

Seems it did not I had a pre MOT done and was told emissions "need cleaning up" I took it to a test only place, they do not fix anything.
I have new plugs, air filter ,Land Rover MAFF sensor and engine light is not on.I have a Nanocom and says no faults.

So I do not know what to do.
I am told that emissions have been tightened up which was new to me.
I am aware of places like Tornado Systems who tune Discos to go fast, but all i want is it to go with lower emissions.
If it was my old motorbike i would twiddle the mixture screw and then adjust the tick over.
The Bosch Motronic does not allow this

It does go well so am a bit lost as i assume it needs to go somewhere and be plugged in to reduce emissions.? or would I remove the ecu and get his set up differently?

any guidance would be great

Emissions have indeed been tightened up, but new rules don't impact old vehicles. The emissions requirements are the same as when it was built.
Air leaks and exhaust leaks are the first things to check when emissions are off.

Thank you I will start looking.

dead o2 sensors would be my suspicion..

Or it needs a good thrash.

maybe both!

MAF sensor too..

MAf sensor is new,I did wonder about O2 sensors,but an Indie garage said do not replace unless they are faulty, maybe they are.
It’s a lot of money if what I have are okay.
I was told the engine fault light comes on when they go down,is that correct?
It might need a good thrash as I do not do that…so in the morning we will see

O2 sensors can get sluggish before they stop responding completely and throw the check engine light. The first symptom is usually a noticeable drop in miles per gallon

westone said:

MAf sensor is new,I did wonder about O2 sensors,but an Indie garage said do not replace unless they are faulty, maybe they are.
It’s a lot of money if what I have are okay.
I was told the engine fault light comes on when they go down,is that correct?
It might need a good thrash as I do not do that…so in the morning we will see

Click to expand...

Both 02 sensors on mine died and apart from the 11mpg thirst there was no other sign, well apart from the emissions!

Thank you all.
I checked exhaust and intake cannot see any air leaks.
Been out for a high speed drive and went very well.

Fuel is about normal 16 mpg on a run and 12 around town.
Its really going well..pulls very fast through the gears.
I did wonder if a dyno tester would help.
I would not be able to fit the O2s myself and with buying them looking at £600.
Thats mail order Bosch sensors ,well am told they are JLR want £170 each and I am told they are the same.
I will have to think some more
Checked Nanocom after my run sayes all is good ..no faults.

If the Nanocom says it’s good then it’s good. BTW… £170 for an O2 sensor is ridiculous.
Some people prefer Bosch O2 sensors for our Thor V8 engine but I don’t like them. Search online for NTK brand part #25623 UP & #25624 DOWN or Walker brand #350-34462 UP & #350-34188 DOWN.

Thank you I will pursue that. I just went for Bosch as read on here that JlR ones are Bosch and as the system is Bosch I thought I would give it a go.
Going for a long fast drive tomorrow and then going to check with Nanocom again.
I may get emissions re checked at another garage to be sure as Disco is going so well and all I read is that with duff O2 cells you notice bad running.
I will update