What setting controls idle max %

[KFXGUY]

I'm having a slight issue with idle. Tune is perfect. Car runs perfect. Everything acts as it should.....until I get a random hanging idle %. Let me elaborate.

After driving for a while, things heat up. The tolerances (i'm guessing) get looser on my throttle body. I'm not going to say what name brand it is for sake of not throwing any company under the bus, but its a $400 one I bought brand new, not a china one. So when things heat up, if I snap the throttle then i assume because of the slack it will return back to less than 0% and remembers that position. when things level out it now says .4%
do it again a couple times and it ends up reading .8%

thats when my surging starts. If i could raise whatever setting it is affecting this at .8% then it should stop my surging. I just dont know what that is.

I can watch all of this play out on my scanner. Throttle body has a good bit of slack. My china throttle body i have sitting on the shelf has zero slack. I've put a new tps about 3 or 4 times.

2004 gto LS1

[charcoal03silvy]

If there is a setting for it available for us to change I have overlooked it. TPS not being zero (0.4) is for sure your issue. Have you tried clocking the TPS further back? What is your TPS voltage?

[KFXGUY]

If there is a setting for it available for us to change I have overlooked it. TPS not being zero (0.4) is for sure your issue. Have you tried clocking the TPS further back? What is your TPS voltage?

Well ive tried numerous things. I understand now why its doing what is is. Ok, ive verified this with my scanner also. Say i have it set at .55v (ive tried .47, .55v, .57, .59, etc etc).....if i screw the throttle screw a little to close the blade, the ecm will instantly remember this position. so imagine if my shaft has slack, i let the throttle shut quickly and the slack allows the throttle to shut a tad bit more than it can.....guess what? it now just relearned this position and when the shaft settles as normal, it now reads .4% . when the engine heats up itll get up to .8%

You can try this as an experiment if you want. open your scanner, start the engine. let it idle. note that its 0% , screw the throttle blade in some and then back to the same position. You'll see its remembered a different position. it will reset to zero if you turn the key off for 2 minutes.

[Area47]

What throttle body? I have run up to .75 on some setups to get the iac to regain some control. that is walking into the gray area of idle vs off idle.

[KFXGUY]

What throttle body? I have run up to .75 on some setups to get the iac to regain some control. that is walking into the gray area of idle vs off idle.

Its a 92mm billet throttle body. I'm refraining from giving the name brand because i'd rather not make them look bad. I'm sure its just a simple defective one that got past quality control.

[charcoal03silvy]

If you're using a junk TB that is likely your issue... Refraining from posting the brand isn't "not bashing them" its just hindering us helping you further. I have had a lot of issues out of cheap brand aftermarket TBs.

[Area47]

Its a 92mm billet throttle body. I'm refraining from giving the name brand because i'd rather not make them look bad. I'm sure its just a simple defective one that got past quality control.

if its a fast, or holley. this is most likely your issue.

[KFXGUY]

If you're using a junk TB that is likely your issue... Refraining from posting the brand isn't "not bashing them" its just hindering us helping you further. I have had a lot of issues out of cheap brand aftermarket TBs.

Man, the throttle body i was having trouble with is a name brand. One that everyone on here has heard of and swears by. I bought it brand new about 5 months ago from the ws6 store. It cost me around 400 bucks. I cheaped out initially with an ebay unit, which i fixed all the issues it had and then bought this one thinking the car would be less touchey...and it was...but it caused me lots of headaches. I kept denying to myself that the tb was the issue. Until i saw it had slack and THE CHINA ONE DID NOT. Put ole china one back on, problems disappeared. Expensive TB was shipped back to the manufacturer yesterday.

[KFXGUY]

if its a fast, or holley. this is most likely your issue.

Not either one of those. see the reason i didnt post the brand name is because i bought the one that usually has no problem. but stuff does happen and the owner is taking care of it.

[KFXGUY]

So nobody knows how to raise the idle conditions throttle percentage?

[Frost]

You can't really do it, you have to fix the physical issue. The 102s can be even worse; the vacuum at deep decel can pull them further "shut" and the update with that new learned position that is BELOW reality for actual idle. If it shows 0.8% or more, it will prolly stall returning to idle as adaptive will not begin. The work around isn't opening the allowed range (which seemingly can't be reliably done) but SLOWING the return to idle most of the time through IAC padding.

[KFXGUY]

You can't really do it, you have to fix the physical issue. The 102s can be even worse; the vacuum at deep decel can pull them further "shut" and the update with that new learned position that is BELOW reality for actual idle. If it shows 0.8% or more, it will prolly stall returning to idle as adaptive will not begin. The work around isn't opening the allowed range (which seemingly can't be reliably done) but SLOWING the return to idle most of the time through IAC padding.

This is EXACTLY what’s happening. Now that you mention it, I do notice the throttle percentage start doing that under deceleration. Exolains why I can drive around all day at low rpm and it’ll be fine. Then get on it a few times and let off and let the car coast and it produces more vacuum.....then my problem starts. So how do I set the iac to bleed off some of that? Your help is greatly appreciated.