ULTM8Z

Is there any way to bias the O2 voltage at idle speeds? I'm thinking my engine could benefit a little by running a little richer at idle, but I don't want to mess with the stoichiometric value because it runs so good everywhere else. I'm thinking if I can bias the voltage down by say 100 mV or something, I can get the computer to add a little more fuel.

I know there's an AIR divert voltage bias, but that doesn't work at idle speeds. Or can it?

Thanks.

For instance, in the constants section, what is the Fast O2 R/L threshold at idle? Or the R/L Threshold hysterisis at idle?

PLANT PROTECTION

iTrader: (6)

Here is a pretty recent thread on the topic.
---> https://www.thirdgen.org/techbb2/sho...hreadid=215238

Grumpy

Go open loop.

Might try different timing values at idle. Depending on the cam, and exhuast, the self EGR effects can be profoundly different from one car to another, so it takes some playing with the timing/fuel to get best idle.

ULTM8Z

I've been all over the place with the timing. Pretty sure it's set right since it's at the point now that if I change it, it runs worse. BLM is a perfect 128 as well. GM recommends ZZ4's be run at 10 with vacuum advance disconnected. I started with that value at 100kpa and iterated from there- working backwards along the kPa axis at idle speed. I iterated until I got the idle quality as good as possible. With my cam, I found that I need a couple more degrees.

Plant Protection- I read through that thread and it seems to be what I was looking for. But it didn't end with a definitive answer. One problem I'm trying to cure is what Traxion was complaining about- that awful smell. RBob said that he's using the following

Quote:
OK, here is what I've been using:

486mV, mean R/L O2 val for idle
501mV, mean rich O2 val for idle
466mV, mean lean O2 val for idle

RBob.

But I'm not sure what these values would correspond to in Tunercat.