Quote:
Originally Posted by MaxedGT  HC's are unburned fuel, but if you were rich CO would be high too. Advancing the timing at idle and raising the idle speed would help. The cams are likely the cause. If you're missfiring at idle that will also cause high HC. |
Yeah, that's the thing: the other measured parameters don't look that bad. Even at idle, with HCs off the scale, the CO% is pretty low. Weird.
I think the cams are the cause of the HCs and the MRT pipe lacks the catalytic capacity (or quality) to deal with it all. I'm tempted to slap the OE H-pipe back on and try it again but want to go back to my tuner first to have him check the scalars for the 24# injectors and bump the idle to 1000RPM. I'll get his thoughts on advancing the idle spark advance as well. If the problem is more overlap from the cams and mixture leaking out the exhaust valves during this time, a timing advance probably wouldn't help. But these guys are local and I'm sure they've dealt with a few modded MGTs facing the province's sniffer test.
But damn...these are supposed to be mild cams. I can't imagine what "stage 2" cam guys are doing in these parts...