Quote:
|
Originally Posted by b3lha
Does HC mean hydrocarbons? ie. Unburnt fuel vapour in the exhaust.
|
Well, it means unburnt hydrocarbons, but it might not be fuel, it might be oil vapour
(any visible smoke?).
The other figures would help the diagnosis, if the CO was high then you would suspect overfuelling and then might want to look at the oxygen sensors. But if the CO is low, which I suspect it is (otherwise he would have mentioned it), then it could well be oil..........
But, on the other hand, if he reports a slight misfire/hesitation then it could be an occasional cylinderful of uncombusted fuel getting in the exhaust.
You just can't tell at this distance.
I wouldn't encourage him to run out and buy new cats unless he was sure they were going to help.
Pulling any stored codes might well be a help in diagnosis.
In short, I dunno.