eignub

so we are having trouble getting my 88 through emissions testing. here are the results. since the first time was so close i didnt really do much before the second test besides check all the vacuum lines and tried a bottle of that guaranteed to pass stuff they sell at all the auto stores. the second time the loaded HC was lower, loaded CO was higher, idle HC was lower, idle CO was higher (more then doubled)

GRohr

See if it is running rich. CO levels rise dramatically the richer you run. You could check the MAP or maybe O2 sensor maybe.

Here is a figure from "Engine Management Advanced Tuning" by Greg banish. A very good read. Leaner will drive down CO and HC but drive up NOx so there is a balance.

DFlintstone

See #27 in Cruisers tips. (found on-top in my sig). Cap/rotor and wires are clean and the plugs are gaped to .035?

For what it's worth, I ran some Chevron premium with techron before smogging my 90 a bit back. It did way better numbers than it's last smog in 2011. I wouldn't add any "additives". Likely that would just mess things up.

cruiser54

If the ground circuit to the engine sensors is bad, they will not work properly.

This is affected by the things outlined in my Tips 1 through 5, and 27.

Ever put an oxygen sensorsor in it? Use NTK brand. And YES on tuneup parts per Flintstone.

eignub

Got it through, though just barely. I replaced the 02 sensor, cap, rotor, plugs, and wires. The HC went way up, but the CO got cut in about half. Any indication of what might be the problem since its still cutting close o HC now? The readings now were
Loaded HC: 219
Idle HC: 198
Loaded CO: 0.97
Idle CO: 0.85

I had asked my lady to clean up the grounds per cruisers direction, but i dont think she ever got around to it.

cruiser54

Dipstick tube grounds are super important!!!