*HELP*MOT Emissions failure again!!!

Advertise with us
Shop deals on ebay
shop deals on amazon
Twingo Forum

Help Support Twingo Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
C

Calbriggo

Well-known member
Joined
Mar 22, 2012
Messages
80
Reaction score
0
Hi Guys,

My twingo 133 has just failed its mot for the second time on emissions. I have a k tec cat back exhaust fitted with 1 silencer. I have also replaced the spark plugs and I have done everything i can think of except put a standard exhaust back on??? Any ideas anyone because I'm completely stumped with this one.
 
Calbriggo":2363qmk8 said:
It has to be one of the lambda sensors. Cant think of nothing else.
Click to expand...
Engine not up to temperaure, so still having warmup enrichment
Failed cat.
New but incorrect plugs fitted.
Failing ignition coil.
poorly injector.
Exhaust valve passing.
Mapped too rich
coked up and needing a good clear out

What did the old plugs look like when they came out?
 
Did you take it for a good chav drive before the mot? The cat may be all clogged up.

Is the mot testing station properly warming the car up before the test? (Letting it sit and idle doesn't count)

I chucked some redex in my clio which lowered the emissions (also needed a coil pack)
 
The old plugs looked fine tbh changed at 21600 miles. Pretty sure the new ones that went in were the same as the old ones, the numbers on the new sparks matched the old ones.

The engine was proper hot when the emission test was undertaken, it was just soooo far over it went 2.8% Co2 on fast idle. Which makes me think that there is a more serious under lying problem. The ktec exhaust should have no effect on the emissions should it? The car is totally standard apart from the exhaust.
 
Im going to renault in the morning to have the N/S balljoint replaced as its badly worn because the rubbers failed common prob i think.

I'll ask them to do a lambda test while im there, then that would rule that out if it comes back no fault.
 
Any noticed missfires or pinking? Do you feel a slight loss of power when you accelerate? Any white smoke coming out the exhaust? Did you remap it before it failed its ticket? A whole world of possibilities exist man, take it to a mechanic you trust. None of us can answer you without taking a gander under your lid. Won't be a lambda sensor failure don't worry about that, an engine management sign would pop up on your dash if it was
 
No missfires or anything like that. It does feel slightly sluggish on acceleration, some white smoke is coming out of the exhaust mainly when its warming it up though.

There is no remap on it completely standard map.

The mech said that it could be a lack of back pressure in the exhaust system but im not sure on that one.
 
That's usually normal for your engine to run lean on a cold start, I believe it may be the ignition timing, it sounds as if its sparking ever so slightly after it should which will explain the slight loss of acceleration but its best to get that checked by a specialist. Don't worry though, not the end of the world
 
Yeh I will get it checked out by a specialist. Its not the end of the world its just very annoying that it could be so many different things. Thanks for your advice mate.
 
Calbriggo":229mnr1l said:
Tecoot":229mnr1l said:
Lambda!
I have this problem...
Click to expand...


Did your lambda fault come up on the dash as an engine management fault?
Click to expand...

No!
After changing Lambda i have better fuel economy :)

Sorry for my poor English :(
 
Mine may have that fault with lambda. Mine is awful on fuel doing about 20-25 mpg ATM i reckon lol
 
The car is in Renault this morning having the lambda sensors checked. I'll update later on what they come back and say
 
Right ok, Renault have checked the lambda sensors and they say they are fine no issues, They performed an emissions test as well and according to them it passed on emissions Hmmmmm. Someone is lying lol
 
Top