SSkeet

Im tuning for a 408, what do I look at in autotap to check the idle air count? There are a few things and I am not sure which one it is exactly.
Also, I remember a way to tweak the TB in order to change the idle air instead of drilling it out...any1 know what Im talking about? If so, please explain. Thanks

Another_User

https://ls1tech.com/forums/showthrea...=stop+drilling

SSkeet

If you have LS1 Edit do you still have to do this to adjust IAC or can you adjust tables in Edit????????????????????? Like Park and Idle Air tables...???

wait4me

iTrader: (10)

depends on if its a electronic throttlebody or cable driven.. with a 408 you need to have more air enter the engine at idle than the motor can handle to be smooth transitions so you need to change all your idle tables by the percent of change on your cubes..
sometimes with a big cam you cant make enough needed air with turning only the throttle blade. so a hole has to be done. but like ive said for a couple years now on www.ls1tuning.com, you should try the blade adjustment first.

Rick@Synergy

iTrader: (5)

I would put your counts at about 40-50. Use the set screw and fix the TPS voltage to do this without messing up other things. Works perfect everytime.

Rick

Another_User

Make sure you let your engine get good and hot. 40-50 IAC counts when your engine is not fully warmed could mean 0 when it is. And that is not good.

Rick@Synergy

iTrader: (5)

Yes, warm engine important. Sorry I left that one out. Thanks for the back up.

Rick

SSkeet

Thanks guys, so I should set the park and idle air tables to somewhere in the range 40-50?

Or do you mean I should monitor the idle air counts and get them to SHOW 40-50 range? I always assumed idle air counts in the high 20's, but what you are saying is, for this motor the idle air counts should be in the 40's???? Is this right?

Another_User

No, adjust set screw until it idles (while hot) at 40-50 IAC counts. Leave tables alone. If you still have some issues after doing all the other procedures, and an idle relearn, then bump up your running airflow table a little.

SSkeet

When I start it, seems to run ok, wideband shows 12's and 13's and then when it goes into closed loop it goes lean off the scale...
IAC's are like 160's. What does this mean? Do I need to adjust the screw to get the IAC's to come down? Is this what is causing the lean condition?

I know how to tune for my injectors, I have done it on this car and other cars with diff injectors before, so I am pretty sure my IFR is right. Must be something else, but what??????