Idle issues after Auto VE tune

[heavyfoot]

Performed head, cam, intake, header, exhaust swap. Car has been idling bad. Went thru Auto Ve tune. Now car is idling worse. Thought about adjusting throttle blade to let more air in but when warm IAC counts are around 70. What next? Adjust MAF table?:Eyecrazy:

[heavyfoot]

I guess I should also mention that I have and would like to return to MAF closed loop control. Having read more threads I'm really thinking I need to adjust the MAF. Can someone direct me to a procedure to recalibrate the MAF?

[dfe1]

I wouldn't recal the MAF-- it probably doesn't need it. What you're trying to do is to rework the settings so that the engine receives the proper amount of fuel at idle. MAF calbration is certainly one of the tools you can use, but I think you'd be a lot better off using the VE table. If you alter MAF calibration, what you're really doing is telling the PCM that the engine is using more or less air than it actually and that causes the system to alter fuel flow as a response to the false data that indicates an increase or decrease in air flow. On the other hand, what has really changed is VE, so why not change that table, and work directly with a variable that has changed? The VE tables for MAF and SD tunes are very different. Auto VE is really designed for SD, and that's probably the reason your engine runs worse after AutoVE. I think the best approach is to go back to your original MAF tune and make changes from there. You can get part throttle A/F ratios dialed in my logging LTFTs and changing the appropriate cells in the VE table. To get the idle dialed in, work with ignition timing and the VE table to get spark and fuel right and work with the desired air flow table (B4307) to get the air flow where you need it at idle.

[Redline Motorsports]

How big of a cam do you have in it? How do you define idling bad?? Surging, low/high, etc....

How much timing do have at idle?? Is it stable? Bigger cams tend to need a bit more timing at idle to stabilize. How is the AFR at idle??

Howard

[Tre-Cool]

I would go for adjusting idle via timing. Use the BIDI controls. my car idles smooth as silk with about 26-28. anything lower and it rocks the car.