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Mot emissions
- Thread starter car.crash
- Start date
Clio 182 LY
Could be lambda failing, even without a light. You'll need to check the live data if you can however the fact it's using more fuel would suggest a pre-cat lambda issue.
Did they test the car once it was fully warmed up? If the car isn't FULLY up to temperature then that can effect the emissions quite a lot. You could also try some of the treatments available, perhaps someone with more experience of them can advise you.
Did they test the car once it was fully warmed up? If the car isn't FULLY up to temperature then that can effect the emissions quite a lot. You could also try some of the treatments available, perhaps someone with more experience of them can advise you.
Clio 182 LY
Get the MOT Tester to do the emissions check first, and give it a good 30/45 minute drive on dual carriageways/motorways if you can to get the cat/exhaust as hot as it is going to get, and all the sensors to be fully functioning as they should as well. Allowing it to idle, even when showing the temp probably isn't enough to get it through a PASS, where as a good "Italian tune up" more often than not is the difference between a pass and a fail, especially as it's only a small bit out. Do you have a copy of the emissions sheet you could post up?
Car had just done a 30 min drive on the motorway, she was certainly hot.
I've no idea what the actual emissions were because it would have failed if it was left on test, say no more!
I've recently had injector problems but swapped them and it had just been on a solus scanner and that said about the misfire and no lambda issues.
I didn't think the pre cat lambda could adjust the feeling much and the maf sensor did most of the work?
Thought the lambda just trimmed it. Correct me if I'm wrong.
I've no idea what the actual emissions were because it would have failed if it was left on test, say no more!
I've recently had injector problems but swapped them and it had just been on a solus scanner and that said about the misfire and no lambda issues.
I didn't think the pre cat lambda could adjust the feeling much and the maf sensor did most of the work?
Thought the lambda just trimmed it. Correct me if I'm wrong.
Clio 182 LY
Lambda controls it really, as that is where the ECU gets it's emissions data from and then adjusts the fueling accordingly, the post-cat one doesn't matter so much. If money is an issue, you can try swapping the two lambda sensors over if the first one has failed and the second one is functioning as it should. They should have given you a sheet with what it failed on emissions wise, or did they abort the test? If so did they offer any thoughts on a fault? If it's lambda, the emissions sheet should point towards that in regards to the figures it shows that's the only reason I asked.
The test was aborted
He suggested a lambda problem but wasn't sure so thought I'd ask people on here with real experience on them.
I've a obd scanner that will tell me lambda readings but unsure what's right and wrong with what it shows up.
I've no fail sheet but he said 7% over on emissions and a blatant fail.
He assumed I'd smashed the inners out the cat, I'm on the assumption the cat is intact because the car came with a decat and the noise doesn't sound like it's cored out so I'll rule that out for now.
He suggested a lambda problem but wasn't sure so thought I'd ask people on here with real experience on them.
I've a obd scanner that will tell me lambda readings but unsure what's right and wrong with what it shows up.
I've no fail sheet but he said 7% over on emissions and a blatant fail.
He assumed I'd smashed the inners out the cat, I'm on the assumption the cat is intact because the car came with a decat and the noise doesn't sound like it's cored out so I'll rule that out for now.
Clio 182 LY
Get the car hot, and then take a photo of the O2 sensor readings at idle, and at a steady 2000rpm (if you can)...
I'd guess it's the O2 levels that are 7% too high... The pass figure I think is (max allowed) 0.300 so 7% over that is quite a bit, which COULD point to an empty catalyst, but could also point towards a failing lambda.
I'd guess it's the O2 levels that are 7% too high... The pass figure I think is (max allowed) 0.300 so 7% over that is quite a bit, which COULD point to an empty catalyst, but could also point towards a failing lambda.
Clio 182 LY
O2S11 is pre-cat lambda
O2S12 is post-cat lambda
Those readings are very similar to mine, however I'm running a de-cat! (second sensor shows nothing as the information it's reading is identical to the first). How does the car run? And idle? If you delete the code, and it returns then you've certainly got a problem with cylinder 4. You could try swapping the injectors around to see if the fault changes cylinder (indicating an injector fault, just replace with new don't bother cleaning it). I'd start with that, and go from there personally...
O2S12 is post-cat lambda
Those readings are very similar to mine, however I'm running a de-cat! (second sensor shows nothing as the information it's reading is identical to the first). How does the car run? And idle? If you delete the code, and it returns then you've certainly got a problem with cylinder 4. You could try swapping the injectors around to see if the fault changes cylinder (indicating an injector fault, just replace with new don't bother cleaning it). I'd start with that, and go from there personally...
Clio 182 LY
Yeah ignore bottom sensor bud.
PH2 172
Some where that will won`t let you drive home if the wheels are about to fall off, because they care about you, but don`t give a toss about emissions.
Clio 182 LY
Wait, it passed the mot?
I confuse the maf and map.
I've swapped the Map as a precaution a few months back.
I'll fire it back up tomorrow and get a further reading for longer on what the sensor is doing and if it's not raining I'll swap injector 4 as I've spares.
Clio 172
