Nailing down idle tuning...

My MAF, VE, spark, and IFR tables are done. Now I want to tune the idle the best I can. I did the normal +4 ish on the base idle airflow then after the MAF table was done, I matched the idle MAF Hz cells to the idle airflow table (it was pretty close already). I played around with the cracker airflow table a couple months ago and the now the idle is 1200 rpm until the car makes a dead stop again. Besides that, I logged an hour drive watching the IFR vs AFR histo and the AFR runs rich at idle. Cruising the IFR is less than 1% error, idle is 2-4% rich error. If I just barely hold the gas to get it out of idle, AFR is solid again. Do I just need to work on the base idle airflow table or more than that?

Im planning on going to the strip for some launch practice and want to nail down the low rpm AFRs. I searched this forum last night for more advanced idle tuning and not much luck. Im at my work computer now but tonight I will attach my tune file.

Did you run RussK's base running airflow yet? If not, go grab the cfg from my web site and do that before anything else.

Its been 4 months since I touched any of the idle settings. I played around with it in the garage tonight. I dropped the idle spark table down to 21* and really seems to like it. I also dropped the base idle airflow the same amount as the LTIT was trimming. Dropped quite a bit and the AFR error is less, but it starts more sluggishly.

I used the russk file and added my lc1. Short logs but I did make changes between them. Tune file is the most recent with the matching 0.50 LTIT. It is my final tune file with closed loop enabled etc. I forced open loop on the scanner and a couple a logs I was playing with locked IAC and spark.

Found my problem. The high spark table was 5 to 6 degrees higher than the idle spark table in the idle rpm range. Logged the drive home and everything is great, finally! LTFT less than 2%, LTIT -0.2, less than 2% AFR error across the MAF, VE, and IFR tables. I spent all summer on this and Im not going to bother tuning it better than these spotty <2% error cells.

:chug:

Congrats, glad you found it.

How do I get that RussK idle stuff. When I click on it I get all kinds of funny symbols.

In big RED letters it says:
Right click the files below and save to your hard drive.

Give that a try, it should work.

Quote:

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Originally Posted by sheikss

How do I get that RussK idle stuff. When I click on it I get all kinds of funny symbols.

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save it in your scanner config files then when you open your scanner, open that config file and there you have all the settings. hope this helps.

My idle config file attached in post #3 is RussK modified with an LC-1 and added parameters for a throttle cracker histogram. I originally though my hanging idle rpm problem was the cracker airflow, found the spark hanging high in the chart view. Hope this helps other people.

When you do the idle airflow .cfg should the MAF be on or off, or does it matter?