General Please help high emissions on my beloved Punto

[dastardly]

Took my fiat punto to the MOT garage and it failed with high emissions. The MOT garage have tried to sort it but have failed. Anybody got an idea what might be the problem ?
They have tried all these:
Emissions test

1st fast idle in range 2500 - 3000 where my car was tested at 2526 rpm
Allowed: My Car
Co limits 0.30% 9.99%
Hc 200ppm 515ppm
lambda 0.97 - 1.03 0.707

2nd fast idle in range 2500 - 3000 where my car was tested at 2703 rpm
Allowed: My Car
Co limits 0.30% 9.99%
Hc 200ppm 505ppm
lambda 0.97 - 1.03 0.696

normal tickover in range 450 - 1500 where my car was tested at 873 rpm
Allowed: My Car
Co limits 0.50% 7.11%
Hc 200ppm 505ppm
lambda 0.97 - 1.03 0.696

diagnostics test on electrics

block pressure test - (it's had a recent head gasket change along with the cambelt).

carbereta change

Timing check - was out about 3 degrees out ( MOT people didn't seem to bothered ).

cat checked
exaust checked

you name it, it's been checked and has passed all above except emissions.
However, I have been told today that using a meter the "Data" was OK

The car runs perfectly after an initial mis-fire.
Both myself and the MOT garage are at a loss of how to fix.

Any help would be very appreciated.

 

[GhostWKD]

if the timing is out it wont be igniting at the peak point putting a few unburnt drops down the system? mine ran like a pile of pooh when it was just a tooth out

 

[dave]

do you mainly do short and/or slow journeys? if so a good thrashing may help,

 

[Oldschool]

I looks like it is hopelessly overfueling.

Check plugs, leads, coils, make sure the injection unit is fine (even when replaced) and lambda sensor.

 

[hmallett]

I'd try changing the lambda probe. It's fairly cheap to do, and it certainly won't make things any worse!
Just wondering if the coolant temp sensor might be at fault. If it still thinks the car is on the cold cycle it'll run richer.
H

 

[dave]

hasnt got an ebay 20+bhp mod has it?

 

[dastardly]

Thanks but the MOT garage have now told me that they corrected the timing.

 

[dastardly]

The garage have done more checks now
Checked plugs and leads and have also checked the injection unit and replaced the lambda sensor.

You mention coils
The only coil I know is the ignition coil, are there more than one then ?

Thanks Oldschool

 

[dastardly]

Where about on the engine is the coolant temp sensor, will ask the gararge if they tried this sensor ?

Thanks hmallet

 

[dastardly]

Took the car to a Diagnostics garage today and they have now fixed it.
There was air leaking into the Manifold that was tricking the lambda sensor

Anyway thanks for all your replies