Hello,

My '87 420SEL just failed emissions in VA. Here's the readout:

15 MPH HC PPM Limit 65 (70) FAIL 25 MPH HC PPM Limit 119 (113) PASS
15 MPH CO% Limit 0.26 (0.20) PASS 25 MPH CO% Limit 0.38 (0.15) PASS
15 MPH NO Limit 857 (123) PASS 25 MPH NO Limit 833 (259) PASS

The actual readings are shown in ()

The only test I failed was the 15 MPH HC which was so close! Prior to the inspection I replaced the plugs, air filter, and changed the oil. What could be tweaked to bring down the HC by such a tiny amount?

The other thing I don't understand is in 2005, the allowable 15 MPH limit for HC was 134, for CO% 0.75, and for NO 990. How could the HC PPM limit be cut by more than half? If anything, the limit should either remain the same each year or even slightly increase as the car gets older to compensate for normal wear & tear on an engine. Using the 2005 limits, my car would have easily passed.

Could the attendant at the emissions station made a mistake when he setup the limits on his machine? Are the limits for other states the same or can each state set their own limits? I am really trying to figure this whole thing out. Thanks a bunch.

T.C.