Emissions

yourdeadwright

Ok here goes,
I failed my NCT on Emissions, the chap said it BARLEY failed but it did because there was a hoel in the exhaust just before the back box, Fiar enough so i went and got a new exhaust and went and got it retested, now the Emissions are worse !!!!!!!!!!!
How is this even possible, the old one had a visable hole and this is a new one and its worse ??
I dont have the results on me now but ill post them this afternoon,

TheChizler

yourdeadwright wrote: »

Ok here goes,
I failed my NCT on Emissions, the chap said it BARLEY failed but it did because there was a hoel in the exhaust just before the back box, Fiar enough so i went and got a new exhaust and went and got it retested, now the Emissions are worse !!!!!!!!!!!
How is this even possible, the old one had a visable hole and this is a new one and its worse ??
I dont have the results on me now but ill post them this afternoon,

Did you try to heat up the catalytic converter before the test? As in driving around at high speed in low gear for a while? They need very high temps to work efficiently.

DylanII

I had the same issue, I replaced every part possible. Nothing changed. It turned out to be a misaligned timing belt - so I was told anyway, after they charged me a fortune to 'fix' everything else.

I don't see why emissions are even part of the NCT - it has nothing to do with safety.

Mar4ix

what car have you got ? make, model, engine, year, mileage and driving habits. ?

Anjobe

Do you have the emissions details from the 2 test reports? A high lambda reading is quite likely caused by a leak in the exhaust but fails on other readings will have other causes.

yourdeadwright

Its a 00 GOLF 1.4 , About 160 thousand on the clock,
Just drive to work and back really, and dont drive quick or anything,

yourdeadwright

Anjobe wrote: »

Do you have the emissions details from the 2 test reports? A high lambda reading is quite likely caused by a leak in the exhaust but fails on other readings will have other causes.

I ll post the results after lunch don;t have them opn me at the minute, Lamba was spot on,

yourdeadwright

Ok folks
here are my reseults the first time was ,
Lambda 104
Co 0.37
HC 197

Then with the new exhaust

Lambda 102
Co 0.57
HC 237

Mar4ix

there is two readings low revs and high revs CO ... you posted only low revs CO

Anjobe

Looks like lambda was slightly high on the first test, OK on the second but CO and HC are both high then. Probably the exhaust leak was hiding the high CO and HC values on the first test.

High CO means the fuel mixture is too rich, high HC means incomplete combustion. You need to get a mechanic with an emissions test rig to investigate this, most common cause is probably a faulty lambda sensor.

yourdeadwright

Anjobe wrote: »

Looks like lambda was slightly high on the first test, OK on the second but CO and HC are both high then. Probably the exhaust leak was hiding the high CO and HC values on the first test.

High CO means the fuel mixture is too rich, high HC means incomplete combustion. You need to get a mechanic with an emissions test rig to investigate this, most common cause is probably a faulty lambda sensor.

Thanks folks got a friend who works in a VW garage to take the car at lunch time, he just texted me and said when he hooked it up to the computer Lambda sensor came up as a fult in the system, so hopefully thats all that needs replaceig