I was thinking about adjusting my TB so that the motor will idle on it's own with 0 IAC counts. Is this a good idea or bad?

 

I've got mine adjusted down to 4-5 counts at full temp in gear. Works just fine.

 

mine idles on its own with zero iac counts and idle stop screw not assisting(makes contact slightly). that tells me the shaft bushings are worn(sticks occasionally high idle) or air is getting past the butterflies. commanded is 750 and idles 800.

 

Thanks but I know mine will not idle with the blades fully closed unless I were to drill holes in the blades. So I will have to open up the blades with the idle stop screw. Since I the throttle blades will be open farther it will be getting more air at idle, will I have to play with the MAF tables in the idle area to get my BLMs correct?

 

Not necessarily.

All of the air goes thru the MAF sensor. If the engine idles at 750RPM, a specific amount of air was passing thru the MAF, then either pass the blades or via the IAC path. So I dont think it should effect the BLM value.

 

TC602, going back to your first post here: Dont you think its a good idea to give the ECM some room to adjust the IAC to achieve your desired idle RPM? I think a good range for IAC counts at idle is between 10 and 25.

See, if you got things set up at 0 IAC counts for your desired idle speed, you leave no room for the ECM to adjust for varying atmosphere pressure, temperature, and humidity.

Edit: If you follow the minimum air procedure, you set the blades for 450 RPM. Then, with the IAC connected, you are relying on the IAC to make up enough air for another 300 RPM. However, I set the RPM at 650 RPM when I do minimum air, and therefore, only rely on the IAC to open enough for another 100 RPM.

You dont have to burn a chip at all for low IAC counts, just follow the minimum air procedure but for 650 RPM instead of the 450 RPM.

 

Yes I see your point. I will adust for 650 rpm and see how many counts I get. I was just thinking the less control the ECM had at idle, the engine would idle smoother

 

I use 0, since I can sometimes get stalling on sudden throttle lifts. If I try to rely on the ECM, the stall can happen faster then the ecm can prevent it.

Some codes have a timing correct for idle speed, adding a few degrees there can allow for small climate changes, and in those codes, the spark corrections can happen faster then the IAC, and make for a smoother more stable idle, anywho.

 

I thought I remembered you saying something about 0 IAC counts a few years ago, thats why I wanted to try this. I thought you said less ECM control at idle was better. I did a search a didn't come up with what I was looking for and I didn't want to misquote you(thats why I didn't mention you).

 

AH HA I found it here
https://www.thirdgen.org/techbb2/sho...ght=IAC+counts

This is where Grumpy says to shoot for 0 IAC counts.