Renault 0.9 TCE failed MOT on emissions - Lambda & CO
Discussion
Our Twingo failed its MOT today on the emissions test, with CO and Lambda too high on the first test, but only Lambda on the second which seems a little odd.
For context, it's 9 years old and has done less than 20k with plenty of short journeys, but has been regularly serviced.
Last summer it had the camshaft position sensor swapped as it was logging fault codes and getting tricky to start. Since then it's been better but not quite as quick to start as it should be, though there's no codes being logged when I last checked.
Any suggestions on likely cause? Air leak? Faulty MAF or Lambda sensor? Dirty engine from short journeys?
Either way, it'll be going to a garage for investigation but it would be nice to have a clue first.
Fast Idle Test
CO 0.28 (limit 0.2)
Lambda 1.173 (limit 1.03)
Second Fast Idle Test
CO 0.07
Lambda 1.180
Annoyingly it also failed on the windscreen washer jet not working, which I tested earlier today. One of those rare cases where it genuinely stopped working on the way to the test.
For context, it's 9 years old and has done less than 20k with plenty of short journeys, but has been regularly serviced.
Last summer it had the camshaft position sensor swapped as it was logging fault codes and getting tricky to start. Since then it's been better but not quite as quick to start as it should be, though there's no codes being logged when I last checked.
Any suggestions on likely cause? Air leak? Faulty MAF or Lambda sensor? Dirty engine from short journeys?
Either way, it'll be going to a garage for investigation but it would be nice to have a clue first.
Fast Idle Test
CO 0.28 (limit 0.2)
Lambda 1.173 (limit 1.03)
Second Fast Idle Test
CO 0.07
Lambda 1.180
Annoyingly it also failed on the windscreen washer jet not working, which I tested earlier today. One of those rare cases where it genuinely stopped working on the way to the test.
I spoke to a couple of garages today though didn’t have time to give it much thought.
One recommended a tank full of super unleaded a bottle of fuel additive cleaner and a long drive to see if that does the trick before spending any more money.
The other suggested that a lambda sensor replacement would be the best place to start.
One recommended a tank full of super unleaded a bottle of fuel additive cleaner and a long drive to see if that does the trick before spending any more money.
The other suggested that a lambda sensor replacement would be the best place to start.
stevieturbo said:
Alex Z said:
I spoke to a couple of garages today though didn’t have time to give it much thought.
One recommended a tank full of super unleaded a bottle of fuel additive cleaner and a long drive to see if that does the trick before spending any more money.
The other suggested that a lambda sensor replacement would be the best place to start.
waste of money, waste of moneyOne recommended a tank full of super unleaded a bottle of fuel additive cleaner and a long drive to see if that does the trick before spending any more money.
The other suggested that a lambda sensor replacement would be the best place to start.
It's another screaming of an air leak with that very high lambda reading.
E-bmw said:
The first answer to your question above IS the answer, you didn't need to ask any garages, they just want you to pay them to do things/try again.
However as you have asked 2 garages & received complete bullsh!t answers, at least you know NEVER to take a car to them to fix.
Yep, that was the intention. Ask the question and see if they seem to have a clue. However as you have asked 2 garages & received complete bullsh!t answers, at least you know NEVER to take a car to them to fix.
It went somewhere else yesterday where they put it up on the ramps and could tell straight away that there was poor back pressure from the exhaust, almost certainly from a leak at the flexible joint. It’s booked in for them to sort it next week.
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