General Emissions failure

columbiers

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Apr 9, 2013
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Hi,
I have a 2006 1.2 grande punto that has failed the MOT on emissions, attached pic of fail sheet.

My plan was to get the engine nice and hot, it's worked for me on other cars, and then get it re-tested. It hasn't been used a lot this year.
But wondering if there was anything else I should investigate first before taking it for retest. What I want to avoid is buying and changing lots of sensors/parts to find the problem. I have multiecuscan and a multimeter so can do any tests but I'm not sure what to test or even if I need to.
Thanks for any advice
 

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Pull the spark plugs.. :)
See what colour they are.. is one 'odd'?

Is the thermostat sealing properly..??


How long a drive to the MOT station..?
Its worth going 'the long way' ;)
 
OP
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columbiers

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Yes, plugs are all the same condition. Thermostat looks to be sealed fine.

I can run it up to very hot before MOT, just wanted to check that the emissions wasn't indicating a clear lambda or cat failure before I retest? Not sure how bad those readings are?
 
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Im confused how the 1st run had a very low CO..
but the second was miles above the limit

Although the Lambda readings do look a nonsense :eek:

Is the Airfilter clean and dry?
 
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columbiers

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Thank you. Filter is dry and cleanish, it's due a change but it's certainly not clogged up or dirty.
Would the results indicate changing the lambda? Is there any tests I can do on it at home with what I have?
 

GrandePunto PL

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1. Google "punto emissions fail" and read (and ask in the existing threads, don't start a new one). https://www.google.com/search?q=punto+emissions+fail
2. Check for basics like vacuum (intake) leak, breather hoses, EVAP leak.
3. Show us the spark plugs, maybe they are not "OK" (we don't trust you on your "diagnosis" due to your failure at point 1 - you can't Google things).
4. Exhaust leak.
5. FES, MES: oxygen sensors. First should be oscillating at idle (when hot), second one (after cat.) not. There's plenty of material in the web, YouTube videos on "how to" diagnose converter and/or oxygen sensors. No need to start any new thread on forums.
6. FES/MES. Other sensors, like "MAP", coolant temperature.
7. Fuel pressure. Injectors (dirty/leaky).
8. Use car more often (no short trips, no "eco-driving", push it a bit). Consider doing little "Italian tuneup" (in theory this procedure is obsolete in modern cars).
 
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eeeno

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May 16, 2020
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Most usual thing to renew are the ignition coil with ht leads, spark plugs, air filter. Not too expensive just yet.

Looks like that it was running too lean unless the exhaust had leaks. Other possibility is sluggish lambda sensor. You might want to swap the 2nd and 1st , because usually only the 1st fails first.

However I think it may have catalyst failure because the values are way above limits. That's possible if the car was well serviced and anything else is unlikely. I believe that it had been running with poor plugs for quite some time which destroyed the 1st lambda sensor.
 
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columbiers

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Most usual thing to renew are the ignition coil with ht leads, spark plugs, air filter. Not too expensive just yet.

Looks like that it was running too lean unless the exhaust had leaks. Other possibility is sluggish lambda sensor. You might want to swap the 2nd and 1st , because usually only the 1st fails first.

However I think it may have catalyst failure because the values are way above limits. That's possible if the car was well serviced and anything else is unlikely. I believe that it had been running with poor plugs for quite some time which destroyed the 1st lambda sensor.


Thanks. Yes I think I will do HT, plugs and filter, no harm in doing those anyway I think
 
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columbiers

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Just to update, passed MOT today. I changed plugs and air filter, not sure if that had the impact though as both were certainly fine visually. I gave it a very good run immediately prior to MOT, 30 miles at 70mph. Getting it nice and hot seemed to get it right, 0.115 CO and 135 HC so well within limits. Thanks to all those who posted helpful comments.
 
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Just to update, passed MOT today. I changed plugs and air filter, not sure if that had the impact though as both were certainly fine visually. I gave it a very good run immediately prior to MOT, 30 miles at 70mph. Getting it nice and hot seemed to get it right, 0.115 CO and 135 HC so well within limits. Thanks to all those who posted helpful comments.
This is always a worry emissions, but I've made it part of my mot prep on the day to leave an hour for driving on Motorway and dual carriageways, doing 50-70 and getting revs ups to 2500-3000, I find a good 25 miles seems to do the trick , o also I do always put in a bottle of Cataclean a few days before aswell also.
 
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