Emissions test results

The emissions test results show the HC reading to be 1179: the (UK) limit is 1200. So it passed but seems a bit high. I’ve only had the car (308 QV UK spec) for 10 days so I’m getting to know it. And starting a list for “discussion “ with the supplying dealer! Experience of other classics sometimes requires a tweak to pass and an “un-tweak” to run properly. Running seems fine but I have nothing to compare it with.

 

A (catless) 308QV should have much lower HC, but ICE run very well set rich. On a US version 308QV, those extra HC would burn inside the cat(s) and overheat it/them, a euro version doesn't have this issue. Could be a case of the idle mixture just being set too rich -- although that can also be used on a euro version to mask uneven idle fuel delivery from the fuel distributor. Was that HC = 1179 at idle or a higher engine RPM?

For reference, the Mondial8/QV WSM indicates that the euro version 3.0L QV idle mixture should be set to 1.2% CO, but they don't give an HC spec. For the US version, the idle mixture spec, upstream of the cat(s), is a bit tighter at 1.0% CO and 100 ppm HC. You should very easily be able to get down into the couple~few hundred ppm HC area at idle (if everything is working OK).

 

Thanks. The test (for this age car) is done at idle. I need to read up the manual to see how to adjust the idle mixture. I intend to have the test done again in about 6 months so the anniversary does not fall in January.

The cold start mechanism has been disconnected (per previous thread) but it’s starts and runs fine. Experience says don’t fiddle ti

 

Till you know what I’m doing!