Can I adjust this table without messing anything else up? I have researched that this controls the IAC while moving and comparing mine to other tunes, they taper off at ECT of 170deg and above, mine doesn't taper off until 212deg. Might be the cause for my idle hang? I'm thinking of just changing the idle airlfow to match from 170 and up vs 212 and up.
Use my idle cfg file and do a cold start idle scan til operating temp. Don't touch the throttle or move the car while scanning.
Russ Kemp
I've been tuning idle for a week and I don't understand why all the complication with idle air flow, cracker, follower, blah blah... The ecm knows what the idle speed is and should be. There is 1 control mechanism, IAC.. The trims take care of themselves right? So why is it so damn hard for the ecm to handle this task, more or less iac. Damn. Really? Carbed engines can do this without a computer or single moving part.
I put a 230/235 cam in my ls1. It idled fine but would died when I tried to take off. I tried using the config above. I tried this link http://www.hptuners.com/forum/showth...e-(w-pictures) it's all so damn complicated.
I got my take off problem fixed by doubling the over and under speed timing adders and doubling the IAC steps. And lowering follwer and cracker by at least 20%. That last one helped the most.
It's just frustrating.
Last edited by ericwilloughby; 10-06-2014 at 08:34 PM.
Do you have your VE Table set yet? That will help.
As far as the hang, I've got a bit of the same issue. But it hangs at 1200 before settling in to idle. My plan is to reduce the decay times and play around a bit with the timing. If you follow that guide, then a lot of the issues with the cam will go away. It's just fine tuning that will take time.
VE table as well as low end of MAF curve affect idle A LOT, especially cold idle behavior.
You must tune MAF and VE tables with wideband before doing anything else. Otherwise,
wasting your time.
I'm SD only. I tuned the VE with ltft because that's what it's gonna run off of anyway. I've checked it against the wb and it's close enough. I don't think there's any way to run ol at idle only or I'd lean it out there?
Follow the guide. He shows you how to run OLSD for idle. With a big cam, it's hard to get accurate A/F at idle due to overlap. It's easier to tune by sound and idle quality. If you are running SD, upgrade to 1-Bar SD OS and use the real time tuning to fine tune your VE tables. Or you can just run the bi-directional controls in scanner and dial in the A/F from 14.7 to 16+ and lean it out in steps to see if the idle quality improves. Once you have that set, move to the timing, and again, in the scanner you can disable adaptive idle spark and dial in the spark that changes your kPA readings. Once you no longer see any changes to your kPa, back off 2-4 degrees and re-enable adaptive spark to let it make small corrections.
Point is, the IAC is not used to correct idle. Spark is. But your fueling has to be right. Once spark and fueling are dialed in, you can re-run the RAF and get closer on your airflow targets.
I'm 2 bar SD. VE is tuned. I tuned idle with rtt. It's just overly complicated. I did as said above but I don't see the point in tuning ol with a wide band unless your gonna leave it ol. Otherwise it's gonna run afr off the trims.
Of course the iac corrects idle. Thats it's function. Too set the amount of air needed for idle. Spark is also but for the quick adjustments to stabilize over and under speed
RAF??? I forgot what that is? I may need more work there.
Last edited by ericwilloughby; 10-07-2014 at 03:55 AM.
Yes, the IAC corrects idle, but that's like a step from 1200 RPM to 1000 RPM. Not from 925 to 950. That's much too quick for the IAC to make adjustments.
Running Aifrlow. The desired airflow that you log in the scanner you input under Idle -> Airflow -> Base Running Airflow.
Wondering if you have a histogram graph to log the data as well or details about how to get the scanned data back into the table?Originally Posted by Russ K
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