Idle Log... Does everything look good?

[oakley6575]

Finally got my rear end put back together. The truck has been sitting for a couple months and I just logged idle for a while to see if everything looked good. In the middle of the log, I was lowering idle spark to see if I could get rid of some rich exhaust odor. Let me know what you guys see. Thanks

[oakley6575]

408 LQ block
Callies internals
LS3 heads/intake
Stock LS3 42# injectors

Don't pay attention to the wideband. It wasn't hooked up in this log.

[Ben Charles]

Fuel trims look great, but I don't see you logging STIT's, idle desired airflow, startup airflow, IAC counts seem maxed.

You mentioned this was idle, why do you have TPS input the whole time??

[oakley6575]

It has a dbw throttle body on it. It has always showed a tps% when running. I'm not exactly sure what the IAC does and why it is maxed at 310. Is this something I should be worried about?

[oakley6575]

I logged desired IAC position a while back at it was in normal range. But IAC position always says 310.

[Ben Charles]

Oh I thought you were DBC, that makes sense then. I am not real familiar with the DBW setups but I believe they don't use an IAC valve and just open the throttle to let air in (which shows 11% TPS).

Someone else may chime in, but I believe thats how the DBW works.

[oakley6575]

Yea thats my understanding too. Let me ask you a dumb question. What do STIT and LTIT tell you about idle?

[rfrankb4]

Yea thats my understanding too. Let me ask you a dumb question. What do STIT and LTIT tell you about idle?

I would love some explanation on this as well. I was searching earlier today but did not find anything clear.

Are these modifying fueling or air flow? Do they mess up my VE data when attempting to tune VE and they are active?

[5_Liter_Eater]

It tells you how close your commanded idle airflow is to the actual. The RAF tells the PCM how much air you expect to see at idle at different temps. It starts there and the idle trims get it to where it needs to be. Just like fuel trims you want the idle trims small. Usually running the RussK idle procedure is pretty bulletproof. As Ben said you should be logging desired idle airflow, idle trims, etc to line out the idle.

[oakley6575]

Thanks Bill. I guess I never looked at idle like fuel trims. It makes sense though. I will look at idle trims tonight

[5_Liter_Eater]

Well don't look at the idle trims pre say. They are an indicator of a good RAF. Run the RussK idle config procedure which tunes the desired idle airflow table (RAF). Once you've done that you should see very low idle trims.