Seat Toledo 01 1.8 20v emmissions problem

32red

Recently brought my car in for nct, it failed miserably on emmissions. Results were low idle co=7.28 vol%, hc=343ppm, high idle lamda=0.99, co=0.42 vol%, and hc=55 ppm. Brought car to local mechanic and found no products when he checked diagnostics, however readings were still failing. He tried the following but to no avail, lamda sensor, 2nd hand cat, air flow meter, filters and the usual small things. Problem could not be found and he was extremely puzzled as to the cause as no errors were flagging up in diagnostics. The car is old and not worth much without nct. This is the only issue it failed on in the nct, however I would not be willing to spend much correcting the emmissions and hence will not bring it to the main dealer. It could be something small as all the main options have already been tried. I'm just wondering would anyone have any more suggestions or has anyone ever came across this type of problem before? Any feedback greatly appreciated.

Buford T Justice

This thread may be of help pinpointing the problem

shamwari

Is that engine reaching correct operating temp, and was the live data from the temp sensor read to confirm it is posting the correct temps?

32red

Not 100% bout readings from sensor but engine temp definately settled at midway on the temp dial as it should be. On a cold start there is a strong smell of petrol when idling for a few minutes. I can only assume that the system was checked for vacuum leaks aswell as surely mechanic would have checked this. After engine running for a while petrol smell disipates. I have a friend who is coming home from England with a diagnostic kit so hopefully be able to read all sensor info to troubleshoot. I just find it strange that exhaust emmission specialist cannot source the problem. Obviously it would be a shame to take this car off the road and not knowing exactly what is wrong with it as it could be something small causing incorrect readings.

shamwari

On the face of what you are saying, the smell of petrol suggests overfueling. Again a live data check will show what the temp sensor is reporting, and I wouldn't be surprised if it is misreporting a warm engine as cold. I have seen similar before once on a Volkswagen, albeit with a different engine where it stunk of petrol and the engine was at correct operating temp, but the temp sensor reported something like 6.0C !

32red

Thanks for reply shamwari, I will keep posted what results we come up with.

Technoprisoner

the lambda probe is reading .99? correct

shamwari

The exhaust lambda reading in an emissions test is not an indicator of the what the lamdba (or oxygen) sensor is is doing! It is the ratio of air to fuel in the exhaust gases.