failing MOT emissions

I have read other posts on high emissions both here and elsewhere but have yet to cure mine can anybody help??

History.

W reg, distributor type engine, 126k miles, purchased 6 yrs ago at 50k and never had Head gasket changed as far as I know.

Routine work to pass it’s annual MOT's

Feb 2010, failed MOT on emissions, had recently only been used for short runs so injector cleaner and a motorway run cured it.

Aug / Sep 2011, rough running and loss of power turned out to be a collapsed CAT blocking exhaust. Replaced cat, emissions checked, all ok. (assumed previous MOT had shown first indications of CAT failure)

Feb 2011, failed MOT on emissions.

CO 0.6 FAIL,
HC 87ppm,
Lambda 1.06.

Gave it a blast on a 200 mile round trip on motorway but a few miles from home a split coolant hose on the only rainy day for weeks went undetected. Assumed head gasket but on removal turned out to be a holed piston.

Not desperate so took time to source a used engine. Found one at 60k miles complete with inlet manifold and various ancills. Fitted engine, changed CAM belt and serviced it etc. To my ears and on a road test it was sweet and ran smoother and better than the original.

End of October, Back for MOT, failed on emissions.

CO 0.59 (fail)
Co2 14
O2 0.96
Ppm 101
Lambda 1.024


New Plugs, leads, cap and arm
New coolant temp sensor (appeared and tested ok but only sensor transferred from original engine)
Checked for inlet and exhaust leaks, none found but changed both manifold gaskets,
Ran a fuel system cleaner
Changed oil and filter
Checked breathers were clear
Checked cam timing
25mile run immediately before test

Failed Emissions test


CO 0.69 fail
Co2 13.4
Ppm 106
Lambda 1.015

Changed Lambda sensor (original appeared OK with a DVM test)


Failed Emissions test

CO 0.62
Co2 13.6
Ppm 102
Lambda 1.018

Changed CAT (suppliers finally agreed a warenty exchange) but

Failed Emissions test

Similar readings to the above


So apart from fuel pump and ECU (both are expensive bits) what else is there in the fuel / engine / emissions process that hasn't been changed can cause failure?

We are now flummoxed, I hate to be beaten but I’m getting fed up with cost and time taken.
Can anybody out there give any more ideas?
Can anybody recommend an independent LR specialist that won’t cost an arm and a leg (I’m in S26, Sheffield)?

All the above work was carried out by myself. Emissions checks were by my local (all makes, not Landrover specialists) garage, advice came from them along with my past experience and research on the internet.

That looks horribly familiar,the K series needs a really good Cat - most cheap aftermarket ones just dont have a big enough matrix in them to do enough treatment to the gasses.
I had in a FL 1 with VERY similar readings,from another local LR independant,they had already checked just about everything,I went over it again,with Testbook and scoped everything,swopped injectors etc.
Then I borrowed the 75,000m original cat off my wifes FL and it was fine.With both cats side by side on the bench it was obvious that the matrix inside was nearly twice the size of the new one the other place had fitted.....

goneracing said:

I have read other posts on high emissions both here and elsewhere but have yet to cure mine can anybody help??

History.

W reg, distributor type engine, 126k miles, purchased 6 yrs ago at 50k and never had Head gasket changed as far as I know.

Routine work to pass it’s annual MOT's

Feb 2010, failed MOT on emissions, had recently only been used for short runs so injector cleaner and a motorway run cured it.

Aug / Sep 2011, rough running and loss of power turned out to be a collapsed CAT blocking exhaust. Replaced cat, emissions checked, all ok. (assumed previous MOT had shown first indications of CAT failure)

Feb 2011, failed MOT on emissions.

CO 0.6 FAIL,
HC 87ppm,
Lambda 1.06.

Gave it a blast on a 200 mile round trip on motorway but a few miles from home a split coolant hose on the only rainy day for weeks went undetected. Assumed head gasket but on removal turned out to be a holed piston.

Not desperate so took time to source a used engine. Found one at 60k miles complete with inlet manifold and various ancills. Fitted engine, changed CAM belt and serviced it etc. To my ears and on a road test it was sweet and ran smoother and better than the original.

End of October, Back for MOT, failed on emissions.

CO 0.59 (fail)
Co2 14
O2 0.96
Ppm 101
Lambda 1.024


New Plugs, leads, cap and arm
New coolant temp sensor (appeared and tested ok but only sensor transferred from original engine)
Checked for inlet and exhaust leaks, none found but changed both manifold gaskets,
Ran a fuel system cleaner
Changed oil and filter
Checked breathers were clear
Checked cam timing
25mile run immediately before test

Failed Emissions test


CO 0.69 fail
Co2 13.4
Ppm 106
Lambda 1.015

Changed Lambda sensor (original appeared OK with a DVM test)


Failed Emissions test

CO 0.62
Co2 13.6
Ppm 102
Lambda 1.018

Changed CAT (suppliers finally agreed a warenty exchange) but

Failed Emissions test

Similar readings to the above


So apart from fuel pump and ECU (both are expensive bits) what else is there in the fuel / engine / emissions process that hasn't been changed can cause failure?

We are now flummoxed, I hate to be beaten but I’m getting fed up with cost and time taken.
Can anybody out there give any more ideas?
Can anybody recommend an independent LR specialist that won’t cost an arm and a leg (I’m in S26, Sheffield)?

All the above work was carried out by myself. Emissions checks were by my local (all makes, not Landrover specialists) garage, advice came from them along with my past experience and research on the internet.

Click to expand...

lambda looks ok so looks like the cat is not up to the job,most aftermarket cats are not up to the job,have changed 3 in one year on a fiesta,try to save customers money but ends up more expensive in longrun,stick to origanal

Had a similar experience on my Rover 1.6 K series. Just could not get the Co down. New cat helped but it was still marginal. Tried three lambda sensors but little improvement. Good exhaust system and no air leaks.
Took off exhaust manifold as the Lambda was difficult to fit/check behind manifold and had a good look at it on the bench.
The seating for the sensor was corroded, the thread was not screwing in enough to allow the correct seating of the sensor, although it went tight as expected when you did it up.
The sensor sits between the two exhaust flows and the cast web/lumpy bits inside the manifold seemed too close to the sensor. I cleaned away all of the rough casting between the two exhaust flows with a burr in the drill, rethreaded the sensor hole with a cheapo tool off ebay and cleaned up the sensor mating surface on the mainifold.
Put it all back again and Co immediately dropped well under the required limit and lambda dropped back to almost 1.
I had been chasing that problem around for quite a while before I found the lambda problem - could have been the sensor not in far enough, an air leak around the sensor but my guess that the sensor was just not getting a fair comparison of both exhaust flows due to the duff casting.
That's just what I found on my K series - may give you something else to look at (not too expensive to do either)

I went to the mot as well this morning and glad to say it passed with flying colors. When they tested the emission I saw a figure of 1.04 on the meter. Must say that I drove the car the last 10 kilometers to the station blocked in 4th gear at 120 kmh, guess that blew the filth out of the exhaust