Failed CO @ 2500 rpms

[tris91ricer]

Do those factors affect the CO rating as well? Anyone?

I just did my emissions today, and failed the CO by .2 . . . . . .that's also how much displacement I lost in the swap. Weird!
(Unrelated, I know.)

Who's got some quick fixes to lower my carbon monoxide levels? Do I have to do the isopropyl trick?

[vrg3]

Is your oxygen sensor in good shape? What MAF sensor, ECU, injectors, and IAC valve are you using?

[tris91ricer]

If the IAC is a factor, I can tell you its faulty.

I think I'm just gona use that PASS stuff that they have in schuckls. ..
But I think itd also be cool to just do this the right way. . .

[vrg3]

It may be a factor, yes, because the misfires of a rough idle can hurt emissions. A misfire sends unburnt hydrocarbons and unburnt air out the exhaust ports. The catalytic converter can only oxidize so much of the raw fuel, and the oxygen sensor sees the oxygen in the air and reads it as a lean condition, which in turn makes for a richer air/fuel mixture than is ideal.

If you don't want to (or can't) replace the bad IAC valve, maybe you could pass the test by tightening the cruise control cable until it actually holds the throttle open slightly, raising your idle to 1000 RPM or so. Maybe that would smooth things out.

Wait -- did you fail CO at idle or at 2500 RPM? What were your other readings?

[tris91ricer]

It failed at 2500. I guess I must admit that its a modded car, thus, the need for some sneaky shiat. . .

If I could come up with the ~400 scrill for a new turbo IAC, I'd do it.

[vrg3]

You might try adapting a non-turbo IAC valve. Or just try swapping the electromagnet portion for one from a non-turbo.

But the IAC valve has little, if anything, to do with what's happening at 2500 RPM...

Modifications shouldn't cause it to burn dirty, especially not at idle.

Is your oxygen sensor in good shape?

What MAF sensor are you using?

What ECU are you using?

What injectors are you using?

[sammydafish]

umm... those are mint emissions readings.... there's nothing you're going to do to make it better save for wrapping the exhaust to get the car to light off faster. At idle there isn't enough exhaust flow to keep the cat hot. This wasn't a design issue in the early 90s and you usualy see cats placed significantly far down the exhaust system. In 96 the requirements got a little stiffer and you start to see lots of heat shields to help light off cats more easily. In 2002 much tougher cold start emissions standards came into affect as well as tougher idle standards. You start seeing cats intergrated in the exhasut manifolds, head shielding that's insulated and double walled primary pipes. all this to light off cats faster and keep them hot.

On your old legacy, your O2 is bearly hot enough to get a good reading and your cat is bearly hot enough to work at idle.... basicaly, it's working exactly as designed.

** edit ** now that the original post has changed my post doesn't make sence in context

[Legacy777]

CO is is mainly a result of unburnt hydrocarbons/incomplete combustion.

Again....what is the exact configuration of all the vital sensors/ecu, etc. ie. Vikash's questions.

BTW, I split your post and moved it. Your problem deserves it's own thread.

[legacymax]

How long had it been since you had driven it, was the car hot?

I failed C0@ 2500rpm (i think in part because i have a torque chip installed and my exhaust) but my car had been idling for about 10 minutes in the shop before he tested it.
He then told me to go drive it around for a while and he would test it again. So i drove it around at about 4500+ rpm for about 10 mins and then i pass with 0 CO @2500rpm.
-max

[vrg3]

Yeah, you gotta test 'em hot. When I got my automatic tested last time I kept brake-torquing while waiting in line.