High CO tends to come from an overly rich air-fuel mixture and/or unburned fuel. I don't know the state of tune of your car or the last time the carb was rebuilt, but if it's dumping in too much fuel or not using it up, you should be able to get the car to pass by addressing one or both of those. Start with the easy stuff: fresh spark plugs (Autolite #85), properly set timing, a fresh oil change, tank of gas and air filter. After that, consider a carb rebuild, new plug wires and/or even a new ignition coil, as a weak spark will result in poor combustion. One thing I always make sure of before a smog check is to drive the car for a good half-hour on the freeway, with a few good sprints for good luck. Often an under-warmed-up engine will register high hydrocarbon levels rather than high CO, but high HC is also a result of unburned fuel (or in the case of newer cars, a catalytic converter not yet fully warmed up, not an issue with your '69). What state do you live in, and what kind of emissions testing do they do? (In CA, the car goes onto a dyno and they test at 15 mph and 25 mph, so it's a pretty grueling, or at least revealing, test.) 3.75% CO is a very high standard (meaning not stringent). Also, what's the odometer mileage on your car? Here are the results of the last time I had my '78 NYB smogged. Granted, it's a 17,000-mile car with a Electronic Lean Burn and a catalyst, but note the maximum allowable levels and how far my car comes from it, since this engine was not originally available in CA because it failed to meet emission standards. I offer this only as encouragement that a proper state of tune can help a lot, even on a car that's obviously only driven very occasionally. ------ All numbers are listed as MAX / AVG / MEAS, where: - MAX = the legal maximum allowed before the car fails - AVG = the average figures for all passing vehicles - MEAS = my car's readings 15 mph MAX / AVG / MEAS ------ ------------------- HC (ppm): 175 / 47 / 33 CO (%): 1.17 / 0.20 / 0.13 NO (ppm): 1215 / 554 / 492 ----------------------------- 25 mph ------ ------------------- HC (ppm): 142 / 37 / 43 CO (%): 0.97 / 0.17 / 0.12 NO (ppm): 1075 / 468 / 468 ----------------------------- Hope this was helpful. Let us know what you do and how much it helps! Chris in LA 67 Crown (125,000 miles, and always passed when it had to be tested) 78 NYB Salon (just a 17,000-mile baby) On 6/27/06 10:53 PM, john sadowski at jsadowski@xxxxxxx wrote: > Well, Its that time again. I had to go through emmissions 4 times last year > before finally passing. I went today & it failed the carbon monoxide test > under load. The standard is 3.75 & it went through at 4.98. The other 3 > tests passed by a very comfortable margin. They were supposed to be > exempting collector cars here, but the law has yet to take affect & they > don't know if it will. I've been driving the 69 occassionally now & it runs > pretty well. I was surprised that it didn't pass. > John > > > > > ----------------- http://www.imperialclub.com ----------------- > This message was sent to you by the Imperial Mailing List. Please > reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be > shared with everyone. Private messages (and attachments) for the > Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx > To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm > ----------------- http://www.imperialclub.com ----------------- This message was sent to you by the Imperial Mailing List. Please reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be shared with everyone. Private messages (and attachments) for the Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm