> Another cause is an engine running > lean - look over your air filter housing, any gaskets or rubber boots > between the air-flow meter and the heads, etc. Been over it, but intend to do it again, because I am sure wanting it to be something simple :) > Is your state test just > a visual inspection or do they put a sniffer on it? If they sniff it, > the numbers from that test may be useful. at 15mph: HC ppm 122 vs max allowed of 398 CO % 1.04 vs max allowed of 3.08 NO ppm is 1848 vs max allowed of 2723 at 25mph: HC ppm 125 vs max allowed of 343 CO % 0.86 vs max allowed of 2.98 NO ppm is 1696 vs max allowed of 2523 They also measure % of CO2 and its 14.4, and %O2 = 0.6 pretty much identical at both RPMs I think they are amazing numbers, for no cat, and no EGR system....but perhaps the indicate something I don't understand? > > IMHO this is actually a pretty good test, if you can kill the engine > totally by using a wet rag on the tailpipe. Everyone says its okay, so I am becoming convinced. Just sounds like a brutal thing to do to an old engine... :-) I am thinking that while I do a leak down test, I could also block the tailpipe, and do each cylinder with the exhaust valve open. That ought to give me a quieter, safer way to see if I have issues on the exhaust side..... > > If you can't find anything obviously wrong, like a cracked hose or bad > gasket, it might be a good time for a full tune-up. Twiddling every > adjustment there is every 5 miles will make your engine unhappy, but so > will not touching any of the adjustments for 50,000 miles. :) > Thanks Matt. I appreciate the assist. Unless I miss my guess, there is precious little to adjust, beyond cap, rotor, and plug replacement. The test mechanice does the CO adjust each year when it is needed, and I don't think tweaking the AFM is a good thing, :-) so is there something else I should be dealing with? Based on how I drive it anymore, no more than 3000 miles per year, when I said years, I meant probably less than 20,000 miles....<g> John |
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