I am trying to lower my cars Idle as it is idling at about 850 in Park. Once in drive it will Idle at about 750 but I would like to lower it to about 600 - 650.

I had a look at the chip contents and my tables do tell the ECM to Idle at 600 once above 80 deg C but seems to me even when over that temperature the car Idles at 750.

Are there any other tables that could have a play in Idle speed?

 

Might be several, varies by Mask.
What are you running?.

 

I'm running a 730 ECM base chip was from a 1992 305TPI Z28.

I am using TunerPro but from what I have seen on other posts, I don't think it covers as many tables as Tunercat. Cause some of the tables that are mentioned on this board are not visible in TunerPro or Winbin.

But that has probably got to do with the ECU how many tables are in there.

 

Hmmm, the last time I had that problem, I found out that my tuning software got corrupted and was spitting out bad chips. The ECM would completely ignore me as far as telling it what idle speed to use.

However, with yours it may also be a mechanical setup problem. What are your IAC counts at idle? If it's zero, the ECM is out of of its range of adjusment when trying to lower your idle speed. If so, then simply go back and close the throttle blades a little with the adjustment screw and bring the counts up to about 15-20 in park while at 600 rpm. This should allow the ECM to reduce the air intake enough to bring the idle speed down to your specified value.

 

ULTM8Z, I just went through the IAC counts and you might be right. Won't be sure until I adjust it and scan it.

But looking at the data they tend to be at 0 at Idle sometimes 2-4 but that seems only when they are coming back down to zero and then they stay there until I accelerate again.

I will adjust the Idle with the screw and test it out!

 

Sounds like that might be your problem. The IAC is all the way closed when the ECM is trying to meet your 600 rpm spec. It simply cannot go any further down.