stumped.. smog/aircare on my redtop

[Ryan.maccie]

Alright, so I have a red top,

Ran it though aircare it passed the carbon monoxide test at an idle, although slightly above average readings still well within limits.

It failed hydro carbons 280/98.

So I pulled injector number 3 and ran it through, 376/98..

So I went and replaced the cat, now I am sitting at 170/98 on hydro carbons, at idle. With my wideband stufed up the tail pipe I am seeing 16.7-17.3 at idle, obviously a bit lean, but I have had luck with other vehicles passing in that range.

High hc to me usually means UNburnt fuel, but that is usually followers by high CO numbers wich I am not experiencing.

Hopefully some of the guru's here can shed some light on this because I really don't want to have to start throwing money at the thing replacing this and that.

[Kingtal0n]

did you try some brand new spark plugs with a nice wide gap? Use the OEM heat range, just for the test.

also, the wideband might be picking up on oxygen entering the system before the tailpipe. check for exhaust leaks.

You want to be in closed loop of course, verify the oxygen sensor voltage is swinging like it should be.

As light load as possible will reduce the fuel requirement at idle. Disable accessories such as power steering pump and A/C compressor.

clean injectors with a good spray pattern is important. run some injector cleaner and carbon remover for a bit, if that doesnt help 370cc injectors are a dime a dozen just change them out.

[hassanbakar123]

leaky injector maybe.

[meano_lover]

verify correct timing as well. will bump your co/hc dramatically if off from spec.