Car has Comp 262AH cams, an MRT catted H-pipe, 24# injectors and custom tune. No MIL. Runs great. Gets ****ty gas mileage -- worse than I'd expect but since it runs well and doesn't have sooty tailpipes I figured it was average. Subjected it to a sniffer test today.
First is an ASM2525 40KPH dyno-rollers run. Numbers were:
HC (ppm): 52 (limit 52) PASS
CO (%): 0.01 (limit 0.29) PASS
NO (ppm): 70 (limit 385) PASS
Next was the curb idle test. This is where the wheels fell off:
HC (ppm): 772 (limit 150) FAIL
CO (%): 0.12 (limit 0.27) PASS
So the idle HC output is stupendously high. I'd immediately suspect the MRT cats are bad but except for the high idle HC, the readings are not really all that bad. The car idles well at 750-800RPM, a little lumpy I guess but these are pretty mild cams overall.
I'll get a scanner on it and have a look at the fuel trims I guess. Maybe the tune didn't account for the 24# injectors or something. I'm tempted to put the factory H-pipe with its 4 cats back on and scan it but I'm not sure if even it, with all those cats that are low-miles, squeaky clean and like new, will deal well with that much HC at idle.
Thoughts?