John_D.

iTrader: (2)

The closed loop idle is too rich. (based on the strong exhaust)

I'd like to fix it. But closed loop is insistent on using the o2 voltages...

New o2 sensors.
Recent dyno session (2 days ago) and my wot a/f ratio is right on.
Cruise ltrims are -5 to -3.

I'm suspecting cold o2 sensors. MAC midlength headers. (Shouldn't be as bad as long tubes though, I would think.)

How can I fix this?

Can I disable closed loop at certain rpms or tps settings. (HPtuners). I haven't found a way to do this.

Any other thoughts? (ve, iac, maf table, etc will all be "learned out" via o2 voltages) Pulse widths are 3.2-3.3 on a 700 rpm idle. Cam is 224/228/115 581/588.

I'm happy with all aspects of my setup and my tuning, except the rich idle. The guys at work even notice it 7-8 parking spots away with slight breeze....

RPM WS6

iTrader: (3)

In my experiance, VE table changes are permanent. Never had them "learn out". Then again, most of my VE table changes have been to correct warm starting issues, at a time when the O2 inputs are being ignored anyway. But I still don't think the PCM will learn over things that you do with the VE table.

VE and IFR tables have been very consistant places for me to tune personally. Only reason I've ever had to go back over them is when I make minor changes to my setup requiring tuning tweaks.

John_D.

iTrader: (2)

Any other thoughts on this one...?

I had previously tweaked the VE in the 3 lowest columns to get it to idle without having to put a hole in the tb. I could experiment with different values there and see what happens.

But I'm still thinking that the pcm is still going to do it's fuel trim thing, and hit target o2 voltages. And that seems to be the problem area, the pcm thinks things are fine with the o2's but the exhaust is still rich.

Cold o2's might be the problem, but I don't know of a way to heat them any better. It's only midlength headers...

samz28

you realize the misfires from loping results in unburnt gases polluting your oil and exhaust emissions right? The cat probably cant handle all that and it smells like gas (***).

no cat? even more gassy.

John_D.

iTrader: (2)

That's an interesting thought. I'm not sure it's actual misfires though, just erratic crank motion compared to the smooth idle the pcm expects...

My lsa is pretty wide, it's a 115, so that should cut down on the amount of charge that gets out through the exhaust valve.

And the cats, well, you're on to something there too... I have shells, but I'm told there's not too much inside them. (used headers and y-pipe)

samz28

well dude even a stock car with no cats is gonna smell like g(***).

put cats back on if you dont want to cause baby jesus to cry in the car behind you