CO emissions MOT failure
Discussion
Just picked up my car from the MOT. First MOT on MegaSquirt and failed the emissions test on HIgh CO. It passed without any problems on the Lucas ECU last year. Results as follows:
Fast Idle Test 1 - 4.79% limit 0.3%
Fast Idle Test 2 - 2.66%, limit 0.3%
Natura Idle Test - 2.314% limit 0.5%
Only just passed the AFR test so was running a bit rich. I can lean the MAP out a bit at the test RPM, however I'm not sure how much this will help the CO readings.
Considering trying one of the engine cleaning additives. ANyone have any succes with these, just wondered if anyof them really work.
Fast Idle Test 1 - 4.79% limit 0.3%
Fast Idle Test 2 - 2.66%, limit 0.3%
Natura Idle Test - 2.314% limit 0.5%
Only just passed the AFR test so was running a bit rich. I can lean the MAP out a bit at the test RPM, however I'm not sure how much this will help the CO readings.
Considering trying one of the engine cleaning additives. ANyone have any succes with these, just wondered if anyof them really work.
This link might help
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
But as I point out it will not help if you have a fueling problem.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
But as I point out it will not help if you have a fueling problem.
Gave the car a good run before dropping it off, but then left the car at the garage as i didn't expect it to fail.
Going back next week but will arrange a time for the Emissions test so I can drive straight in and get the test done.
My main question was wether it is worth trying one of the engine cleaners, which is what the tester recommended.
Going back next week but will arrange a time for the Emissions test so I can drive straight in and get the test done.
My main question was wether it is worth trying one of the engine cleaners, which is what the tester recommended.
Gave the car a good run before dropping it off, but then left the car at the garage as i didn't expect it to fail.
Going back next week but will arrange a time for the Emissions test so I can drive straight in and get the test done.
My main question was wether it is worth trying one of the engine cleaners, which is what the tester recommended.
Going back next week but will arrange a time for the Emissions test so I can drive straight in and get the test done.
My main question was wether it is worth trying one of the engine cleaners, which is what the tester recommended.
currently running in open loop, but i do have a wide band gauge on the dash.
unfortunately to get a smooth idle it seems to run a bit rich.
I'm going to try and improve the fueling at idle and fast idle RPM for the re-test. Will also look at setting it up in closed loop at these RPM.
unfortunately to get a smooth idle it seems to run a bit rich.
I'm going to try and improve the fueling at idle and fast idle RPM for the re-test. Will also look at setting it up in closed loop at these RPM.
I tried a catalyst cleaning product that claimed a 30% reduction in emissions was possible. It was expensive (I think it was around £15 for a bottle), but it worked in so much the emissions did drop by 30%, but it still failed the MOT due to a fueling error (This was on a modern Fiat). Those figures are so far out you need to get to the route cause.
That's not going to be a case of a thrash round the block as your not trying to clean off Lambda probes as your running open loop anyway 
you need to open the MS software and have a looksy before going any further 
you can trim it at the test centre if you take the laptop with you that gets the MOT out of the way you can then look at the reason why the map as drifted after 
I also get a nicer idle running slightly richer around 13.1 AFR but that is purely because the cam as quite a lot of overlap/duration 
there is absolutely no reason your MOT result should be a problem just because you have an after market ECU fitted ... in fact on the contrary as any minor tweaks can be done on the fly how many production cars can do that? 
you need to open the MS software and have a looksy before going any further you can trim it at the test centre if you take the laptop with you that gets the MOT out of the way you can then look at the reason why the map as drifted after I also get a nicer idle running slightly richer around 13.1 AFR but that is purely because the cam as quite a lot of overlap/duration there is absolutely no reason your MOT result should be a problem just because you have an after market ECU fitted ... in fact on the contrary as any minor tweaks can be done on the fly how many production cars can do that? Edited by Simon says on Sunday 5th August 12:13
What AFR`s do they require at what RPM ? Would it be possible to burn the whole tune on map 2 then tweak and save it at the MOT station,then just swop the map over on the lap top when required or fit some type of switch .is that possible ?
Would a MOT compliant map result in poor idle and performance ?
Would a MOT compliant map result in poor idle and performance ?
Your car would not go through the Cat test regardless of what map you use Daz as you donent have a Cat fitted regardless of what anyone else tells you, yes it is possible ypu could swap between maps while your at the testing station, remember it is all no load running so you don't neccesarily have a car that runs like crap just because you meet Cat limits with Cat fitted of course.
I
I
SILICONEKID340HP said:
What AFR`s do they require at what RPM ? Would it be possible to burn the whole tune on map 2 then tweak and save it at the MOT station,then just swop the map over on the lap top when required or fit some type of switch .is that possible ?
Would a MOT compliant map result in poor idle and performance ?
Mine idles at 13.9 but i find richer the better it is .. Would a MOT compliant map result in poor idle and performance ?
If i did have cats fitted what would be the afr`s at what rpm.
SILICONEKID340HP said:
SILICONEKID340HP said:
What AFR`s do they require at what RPM ? Would it be possible to burn the whole tune on map 2 then tweak and save it at the MOT station,then just swop the map over on the lap top when required or fit some type of switch .is that possible ?
Would a MOT compliant map result in poor idle and performance ?
Mine idles at 13.9 but i find richer the better it is .. Would a MOT compliant map result in poor idle and performance ?
Went back in today with the laptop, leaned out the fuelling at Idle and the fast idle point and it passed the emissions test.
Only problem now is it failed on the wipers not working (sticking on the screen). Had the wipers on all the way to the test centre due to the s
t weather, so a bit annoyed that it should fail at the garage.
Suspect the wiper motor was hot following the emissions test and the guy just put the wipers on and full with a dry screen and burned out the motor when the wipers stopped.
Only problem now is it failed on the wipers not working (sticking on the screen). Had the wipers on all the way to the test centre due to the s
t weather, so a bit annoyed that it should fail at the garage. Suspect the wiper motor was hot following the emissions test and the guy just put the wipers on and full with a dry screen and burned out the motor when the wipers stopped.
angus99 said:
Went back in today with the laptop, leaned out the fuelling at Idle and the fast idle point and it passed the emissions test.
Only problem now is it failed on the wipers not working (sticking on the screen). Had the wipers on all the way to the test centre due to the st weather, so a bit annoyed that it should fail at the garage.
Suspect the wiper motor was hot following the emissions test and the guy just put the wipers on and full with a dry screen and burned out the motor when the wipers stopped.
Well done Only problem now is it failed on the wipers not working (sticking on the screen). Had the wipers on all the way to the test centre due to the s
t weather, so a bit annoyed that it should fail at the garage. Suspect the wiper motor was hot following the emissions test and the guy just put the wipers on and full with a dry screen and burned out the motor when the wipers stopped.
if the w/motor as failed then look for Adrian@ or Adrian Venn on these very forums Managed to fix the wipers although may only be temporary fix and has been added as an advisery on the MOT certificate.
Here's the updated emissions read out.
Fast Idle - CO 0.253%, Lambda 0.989 (Original CO 4.89%, Lambda 0.86)
Natural Idle Test - CO 0.296 (Original 2.314%)
I did have to change back to the original map after leaving the test centre as the car ran very lean, as expected, in the areas where I’d changed on the VE table.
I suspect there is a problem with the way the map corrects for changes in manifold air temperature. During the emissions test the MAT was very high, so less air going in due to the lower density. The megasquirt map didn’t seem to correct for this and therefore the engine was running rich. Leaning out the map at the areas required for the MOT got it though the test at high MAT but was then lean at normal MAT of circa 22 degrees.
I’ll need to have a another look at the MAT correction settings, I’ve previously adjusted this to prevent the engine running lean at high MAT and probably overdid it.
At least I won't have to worry about it for another year.
Here's the updated emissions read out.
Fast Idle - CO 0.253%, Lambda 0.989 (Original CO 4.89%, Lambda 0.86)
Natural Idle Test - CO 0.296 (Original 2.314%)
I did have to change back to the original map after leaving the test centre as the car ran very lean, as expected, in the areas where I’d changed on the VE table.
I suspect there is a problem with the way the map corrects for changes in manifold air temperature. During the emissions test the MAT was very high, so less air going in due to the lower density. The megasquirt map didn’t seem to correct for this and therefore the engine was running rich. Leaning out the map at the areas required for the MOT got it though the test at high MAT but was then lean at normal MAT of circa 22 degrees.
I’ll need to have a another look at the MAT correction settings, I’ve previously adjusted this to prevent the engine running lean at high MAT and probably overdid it.
At least I won't have to worry about it for another year.
angus99 said:
Managed to fix the wipers although may only be temporary fix and has been added as an advisery on the MOT certificate.
Here's the updated emissions read out.
Fast Idle - CO 0.253%, Lambda 0.989 (Original CO 4.89%, Lambda 0.86)
Natural Idle Test - CO 0.296 (Original 2.314%)
I did have to change back to the original map after leaving the test centre as the car ran very lean, as expected, in the areas where I’d changed on the VE table.
I suspect there is a problem with the way the map corrects for changes in manifold air temperature. During the emissions test the MAT was very high, so less air going in due to the lower density. The megasquirt map didn’t seem to correct for this and therefore the engine was running rich. Leaning out the map at the areas required for the MOT got it though the test at high MAT but was then lean at normal MAT of circa 22 degrees.
I’ll need to have a another look at the MAT correction settings, I’ve previously adjusted this to prevent the engine running lean at high MAT and probably overdid it.
At least I won't have to worry about it for another year.
Is the air density slightly different up Scotland Here's the updated emissions read out.
Fast Idle - CO 0.253%, Lambda 0.989 (Original CO 4.89%, Lambda 0.86)
Natural Idle Test - CO 0.296 (Original 2.314%)
I did have to change back to the original map after leaving the test centre as the car ran very lean, as expected, in the areas where I’d changed on the VE table.
I suspect there is a problem with the way the map corrects for changes in manifold air temperature. During the emissions test the MAT was very high, so less air going in due to the lower density. The megasquirt map didn’t seem to correct for this and therefore the engine was running rich. Leaning out the map at the areas required for the MOT got it though the test at high MAT but was then lean at normal MAT of circa 22 degrees.
I’ll need to have a another look at the MAT correction settings, I’ve previously adjusted this to prevent the engine running lean at high MAT and probably overdid it.
At least I won't have to worry about it for another year.
Are you running TPS ?
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