Clio Emissions Test Failure
Discussion
Some advice/opinions would be wonderful please.
2004 Renault Clio 1.2 Petrol
Failed on High Idle CO levels for NCT/MOT
Low Idle CO 0.30 vol% (Limit 0.30%) PASS
High Idle CO 0.30 vol% (Limit 0.20%) FAILED
Lambda 1.00 (Limit not between 0.97 and 1.03) PASS
HC 14ppm (Limit above 200ppm) PASS
Engine Oil Temp 80oC
Am I to assume the catalytic converter is knackered or should I be looking else where?
Some (important?) background, last year I had a coil pack fail and ended up limping home on what felt like only two cylinders for approximately 30km - I'm thinking that is a lot of un-burnt fuel washing through the cat.
Also the car was pretty warm when it went in for the test. I'd arrived early and they were running late so I was sat in the car park for an hour with the engine on to keep the heater blowing. The temp gauge was at around 50% when they took it in. Could that have had any effect?
Any pointers to further investigation would be gracefully received before I start chucking parts at it without necessarily fully understanding the problem.
Many thanks.
(I'll have a dig and see if I can find last years figures, but I think on a pass you don't get a list of the measured parameters.)
2004 Renault Clio 1.2 Petrol
Failed on High Idle CO levels for NCT/MOT
Low Idle CO 0.30 vol% (Limit 0.30%) PASS
High Idle CO 0.30 vol% (Limit 0.20%) FAILED
Lambda 1.00 (Limit not between 0.97 and 1.03) PASS
HC 14ppm (Limit above 200ppm) PASS
Engine Oil Temp 80oC
Am I to assume the catalytic converter is knackered or should I be looking else where?
Some (important?) background, last year I had a coil pack fail and ended up limping home on what felt like only two cylinders for approximately 30km - I'm thinking that is a lot of un-burnt fuel washing through the cat.
Also the car was pretty warm when it went in for the test. I'd arrived early and they were running late so I was sat in the car park for an hour with the engine on to keep the heater blowing. The temp gauge was at around 50% when they took it in. Could that have had any effect?
Any pointers to further investigation would be gracefully received before I start chucking parts at it without necessarily fully understanding the problem.
Many thanks.
(I'll have a dig and see if I can find last years figures, but I think on a pass you don't get a list of the measured parameters.)
They should not have tested a cold engine.....where did the 80degC reading come from ? Did they actually check oil temp ?
And sitting idling for ages really isnt a warm cat or engine so to speak. If the gauge wasnt at normal operating temp, they shouldnt have tested it until it was, and certainly shouldnt have failed one that wasnt.
A good drive may well have had things warm enough to read better, or although I doubt it really needs one, check how well the lambda sensor is functioning, and it may need replaced.
And sitting idling for ages really isnt a warm cat or engine so to speak. If the gauge wasnt at normal operating temp, they shouldnt have tested it until it was, and certainly shouldnt have failed one that wasnt.
A good drive may well have had things warm enough to read better, or although I doubt it really needs one, check how well the lambda sensor is functioning, and it may need replaced.
stevieturbo said:
They should not have tested a cold engine.....where did the 80degC reading come from ? Did they actually check oil temp ?
And sitting idling for ages really isnt a warm cat or engine so to speak. If the gauge wasnt at normal operating temp, they shouldnt have tested it until it was, and certainly shouldnt have failed one that wasnt.
A good drive may well have had things warm enough to read better, or although I doubt it really needs one, check how well the lambda sensor is functioning, and it may need replaced.
Crossed wires?And sitting idling for ages really isnt a warm cat or engine so to speak. If the gauge wasnt at normal operating temp, they shouldnt have tested it until it was, and certainly shouldnt have failed one that wasnt.
A good drive may well have had things warm enough to read better, or although I doubt it really needs one, check how well the lambda sensor is functioning, and it may need replaced.
The car was definitely not cold, it was hot. I drove 30-40km to get to the test centre, then sat in the car park with the engine on to keep warm for an hour or so before the test. The car went in very hot in terms of the water temp that I saw on the dashboard indicator.
They claimed the engine oil at 80oC , I think from observing they ascertain this by pointing an IR probe at the engine block.
I don't think a cold engine could be the problem, I'm more concerned about the fuel wash that went through the cat.
Either the lambda reading is inaccurate, or the cat isn't working sufficiently. The cat relies on exhaust heat to drive the temperature up far enough for it to work so it might simply be that it was not up to temperature, or it may be contaminated. It would be worth giving it an Italian tune-up to see whether it improves with sustained high exhaust temperatures. You might ultimately need a new cat, but I'd have a trustworthy garage look at it and not jump to that conclusion yourself because it's potentially an expensive fix.
GreenV8S said:
Either the lambda reading is inaccurate, or the cat isn't working sufficiently. The cat relies on exhaust heat to drive the temperature up far enough for it to work so it might simply be that it was not up to temperature, or it may be contaminated. It would be worth giving it an Italian tune-up to see whether it improves with sustained high exhaust temperatures. You might ultimately need a new cat, but I'd have a trustworthy garage look at it and not jump to that conclusion yourself because it's potentially an expensive fix.
Thanks, I'll ask around to see if someone will do a test for me.I'm familiar with the Italian tune up, the thought that the car was sat for at least an hour in their car park idling waiting for the test whilst I sat inside keeping warm makes me wonder if that was the problem.
The car drives and feels like it always has. Fuel consumption hasn't changed.
I'm just concerned that I know a whole hep of unburnt fuel went through the cat, and I've read this can cause problems.
Really appreciate your thoughts on this.
GreenV8S said:
The cat relies on exhaust heat to drive the temperature up far enough for it to work so it might simply be that it was not up to temperature, or it may be contaminated.
Would an hour sat idling in the car park screw up that reading as opposed to just arriving and switching off the engine for 20 mins whilst they queue the car for the test?Why is the high idle limit lower than the low idle in that test? Circa 10% difference. What is going on in an engine where there is an expected 10% vol reduction in CO when the engine is above idle revs by a few 1000 rpm?
stevemcs said:
It’s not miles out, when was it last serviced - oil and air filter and plugs, I assume you changed the plugs when changing the coil pack. Any leaks on the exhaust etc ?
^^^^ Wot 'e said.If not done recently do an oil & filter change, fit new plugs & air filter & that will likely be it sorted.
What they said ^ also introduce a load on the charging system i.e lights on demister etc sometimes this increase in cranked throttle to overcome the slight load may just give you the leaner trim you desire for a pass , its a cheat and dont always work however but they cant decline it
JustALooseScrew said:
Also the car was pretty warm when it went in for the test. I'd arrived early and they were running late so I was sat in the car park for an hour with the engine on to keep the heater blowing. The temp gauge was at around 50% when they took it in. Could that have had any effect?
This statement seems clear that it was not fully warmed up ? and an engine sitting idling especially in cold weather with the heater blowing will rarely get fully warmed up, and more importantly nor will the catalytic converter.80degC if actually correctly measured via the oil isnt bad. But in reality most modern petrol engines, normal is in the 90-105degC range.
And sitting with the heater blowing chances of it reaching this in a lot of cars is low.
Really you could do a load of things...but before changing any parts, easiest would be a good run and then re-check emissions when everything is at proper operating temperature.( run being a drive...not a 2 legged run )
stevieturbo said:
ok...although the hydrocarbons clearly show there are no issues with misfire now, or emissions relating to that.
No, but the remaining question is whether the cat efficiency may have been reduced as a result of that, which the CO reading seems to suggest. A good hot blast might help with that.stevieturbo said:
This statement seems clear that it was not fully warmed up ? and an engine sitting idling especially in cold weather with the heater blowing will rarely get fully warmed up, and more importantly nor will the catalytic converter.
80degC if actually correctly measured via the oil isnt bad. But in reality most modern petrol engines, normal is in the 90-105degC range.
And sitting with the heater blowing chances of it reaching this in a lot of cars is low.
Really you could do a load of things...but before changing any parts, easiest would be a good run and then re-check emissions when everything is at proper operating temperature.( run being a drive...not a 2 legged run )
I really appreciate your thoughts on this.80degC if actually correctly measured via the oil isnt bad. But in reality most modern petrol engines, normal is in the 90-105degC range.
And sitting with the heater blowing chances of it reaching this in a lot of cars is low.
Really you could do a load of things...but before changing any parts, easiest would be a good run and then re-check emissions when everything is at proper operating temperature.( run being a drive...not a 2 legged run )
In the past normally I've driven to the test centre, park up, and it could be 10-15 mins until they take it in, so surely that can't be hotter than sat in the car park for an hour watching the temp gauge rising and wondering if/when the fan is going to cut in.
I was only running the heat on low as the car was warm from the drive up there. In fact I wondered if the fact it had been sat idling for an hour before the test was the problem - what if I'd just left it to cool in the car park and sat in their waiting room?
I need to find a friendly local that will shove a probe up the exhaust - I have access to a fully equipped workshop so don't tend to farm out work to any of the locals and hence don't have much or a relationship with any of them.
GreenV8S said:
stevieturbo said:
What fuel wash ? Has there been some other problems with the car you havent mentioned ?
The original post mentioned an ignition fault which probably resulted in a sustained misfire.All plugs were replaced with the coil pack last year.
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