It sounds like uneven cylinder combustion. Could be injectors or even the injector seals or a bad plug wire (occasionally the boots at the plug can be pushed on without contacting the sparkplug properly). Is the test at idle or under load? You might try to use the idle adjustment screws (the brass ones) to smooth out the idle. Harold McElraft - 3354 --- In dmcnews@xxxxxxxxxxxxxxx, "Adam 16683" <acprice1@xxxx> wrote: > My car is still failing emissions! However it is definately better > than before. CO is in control, and HC failed by 0.2!! I dialed in the > CO as best as I can get it with my dwell meter, its hovering right at > 30, oscillating between 28~32. With my CO dialed in my car idles > rougher, and is even worse during warm-up, which is why I enrichened > it in the first place. > > Here some things I have found: the dwell meter reading drops > considerably when the cooling fans activate. The engine oscillation > doesnt change, I am sure it just has something to do with voltage > drops or something. > > Also when the cooling fans activate there is a whining sound from the > engine somewhere, almost sounds like a vacuum leak, but only when the > fans are on! > > And finally a question about emissions: Is NOx inversely proportional > to the HC and CO. It seems that as I decrease CO and HC, the NOx is > higher, and vice versa. > > Thanks everyone! adam > > --- In dmcnews@xxxxxxxxxxxxxxx, "Adam 16683" <acprice1@xxxx> wrote: > > Thanks Andy and Harold. I think you are right that I may not have > > adjusted the mixture how I thought I did. I am going to do what > Andy > > said and get me a dwell meter! > > > > Thanks for the help! > > Adam Price > > > > > > --- In dmcnews@xxxxxxxxxxxxxxx, Soma576@xxxx wrote: > > > In a message dated 10/21/2003 7:33:58 PM Eastern Daylight Time, > > acprice1@xxxx writes: > > > > > > > My car failed emissions for THC and CO. It passed for NOx. > > > > > > >> > > > Now that i finally understand the dwell meter use, let me try to > > help you. > > ..> good luck - it took me 3 years and i'm only now getting my idle > > straightened out the way it should be. but it's worth it to know > > everything is working AOK. > > > > > > Andy