IAC values on a FAST 90mm
guys, there are lots of idle settings that have to be set properly, prime example.
guys car im helping tune right now would run kinda shitty but would run. i made efrfective area changes and it got a LOT worse. after this the idle airflow had to be adjusted so it wouldnt die. now the effective area is dead on and i can tune the idle airflow. you have to get the tps voltage, at least on stock tbs, close to .60 v and then fix the effective area and then fix idle airflwo. there are also some other changes that can be made to help things out even more. its going to get worse before it gets betteer. i did a write up and i dont know if anyone understands what i wrote but if you dont shoot me an email and ill help out. ive got 3 idle configs i use to tuen the idle, one is for all cars and the other 2 depend whether you have a cam or not. budchevy358@yahoo.com is my email. you wont get it right in 1, 2 or even 10 idle tune. i have 11 with a members car on here right now and its just starting to get better. slow and steady chnages from a cold start will get you there. i have over 80 tunes of my car with idle settings alone since the first of june. if you dont have hp tuners but have the same basic idle functions ill let you know what has to be done, now back to work lol
guys car im helping tune right now would run kinda shitty but would run. i made efrfective area changes and it got a LOT worse. after this the idle airflow had to be adjusted so it wouldnt die. now the effective area is dead on and i can tune the idle airflow. you have to get the tps voltage, at least on stock tbs, close to .60 v and then fix the effective area and then fix idle airflwo. there are also some other changes that can be made to help things out even more. its going to get worse before it gets betteer. i did a write up and i dont know if anyone understands what i wrote but if you dont shoot me an email and ill help out. ive got 3 idle configs i use to tuen the idle, one is for all cars and the other 2 depend whether you have a cam or not. budchevy358@yahoo.com is my email. you wont get it right in 1, 2 or even 10 idle tune. i have 11 with a members car on here right now and its just starting to get better. slow and steady chnages from a cold start will get you there. i have over 80 tunes of my car with idle settings alone since the first of june. if you dont have hp tuners but have the same basic idle functions ill let you know what has to be done, now back to work lol
Ok finially I'm getting somewhere! I logged my desiac airflow and found @ 126 deg F it was 18.2 g/s and went down to 16.39 g/s @ 142 deg F and as far as 23.46 g/s @ full operating temp which was 180 deg F My desired IACs went from 172-206 counts as it got hotter but the actual IAC count was 0 the whole time. I started logging @ 126 deg F because the car had been run earlier and was still a little hot so I'll have to wait to get more numbers for cold start. It stayed in fuel trim cell 20 pretty much the entire time which is where it should be.
I found when the car surges the desiac airflow drops to around 8.92 but goes right back arter the surge is done.
I also found my tps voltage to be .70 volts closed and 4.6 volts @ wot. I'm going to sand the throttlebody now to get it to close with out sticking. I already used a peice of tape to fix the tps problem. After sanding it and backing out the screw it should go down where it needs to be. Hopefully this will bring my IAC into range. I'll let you guys know and thanks for the help.
I found when the car surges the desiac airflow drops to around 8.92 but goes right back arter the surge is done.
I also found my tps voltage to be .70 volts closed and 4.6 volts @ wot. I'm going to sand the throttlebody now to get it to close with out sticking. I already used a peice of tape to fix the tps problem. After sanding it and backing out the screw it should go down where it needs to be. Hopefully this will bring my IAC into range. I'll let you guys know and thanks for the help.
when you sand it it may let more air in if its sticking at the blade. what mods you have done? i have stock 346 with f13 and afr heads and all the bolt ons and i see about 9 g/sec hot idle and about 14 g/sec at cold start. what are your idle air trims? you prob need to get that throttle voltage closer to 0.61, although with the 90 mm it may have to be set different. if u still see 0 though i would think you need to decrease it. i have mine set to 0.61 v and i see about 19 on the iac counts when hot. do you see it greater than 0 when its cold?
I have a forged 346, ARE stage 2 heads, 226 226 569 569 112 cam, 1 3/4 hooker headers, and the FAST 90mm set up.
I finished sanding the throttle body and I drilled a 3/16 hole in the blade. I logged some more after reinstalling and the numbers have changed quite a bit.
My Desired IAC count is at 0 now when hot and my actual IAC position is still 0. The desiac was not 0 when I started it but it was still warm and it didn't take long till it went to 0. The tps voltage went down to .4 closed and 4.6 @ wot. The desiac airflow went down to 4 g/sec hot.
The car runs a lot better now and will idle great when hot with no surging when putting it in gear or comming to a stop. I haven't had time to log when cold so I'll have to wait till tomorrow. Hopfully it will idle good cold and I will be satisfied. **** the IAC count! As long as it will idle with out surging and/or cutting off I'm happy. Then it will be off to the dyno for some wot tuning. I'll see how it starts tomorrow log some numbers and let you know.
I finished sanding the throttle body and I drilled a 3/16 hole in the blade. I logged some more after reinstalling and the numbers have changed quite a bit.
My Desired IAC count is at 0 now when hot and my actual IAC position is still 0. The desiac was not 0 when I started it but it was still warm and it didn't take long till it went to 0. The tps voltage went down to .4 closed and 4.6 @ wot. The desiac airflow went down to 4 g/sec hot.
The car runs a lot better now and will idle great when hot with no surging when putting it in gear or comming to a stop. I haven't had time to log when cold so I'll have to wait till tomorrow. Hopfully it will idle good cold and I will be satisfied. **** the IAC count! As long as it will idle with out surging and/or cutting off I'm happy. Then it will be off to the dyno for some wot tuning. I'll see how it starts tomorrow log some numbers and let you know.
good sounds like you got somewhere, so was the throttle haning leaving the tps voltage higher? or did you adjust the set screw. you still wanna get the counts up or it may stall out on you on the street because the car cannot close the iac enough if it has to
Ultraz, you asked how you know if you have enough airflow, well right at the point where desired counts are at zero and the idle speed matches desired idle speed, that's when you have the right amount of airflow. Sounds like you're there already.
Also, fwiw, this problem is completely different from phil99vette's problem (his was a drive by wire 90mm tb). It's also not a problem with having the tb open too far.
Also, fwiw, this problem is completely different from phil99vette's problem (his was a drive by wire 90mm tb). It's also not a problem with having the tb open too far.
my desired idle speed matches my actual idle speed perfect but my IAC count is still 0. My desiac is also 0 when warm. It doesn't look like my iac is doing a damn thing so I'm gonna order a new one like I had planed. If it doesn't work then no big deal as long as it starts and runs good cold tomorrow.
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Verdad Gallardo My desired IAC airflow and my actual IAC counts are both 0 when hot, if thats what you mean? I haven't had a chance to see what they are cold yet but the car definitly runs better now. I'm running SD so if your asking for maf numbers I don't have any.
Started i this morning and it ran great! The throttlebody is no longer sticking and operates smoothly. It's got a little more fine tuning left to do but I'm happy with the results. Can't thank you guys enough!
Another quick question...the iac airflow g/s #s I get do I just transfer those numbers right into my airflow table in LS1edit?
For example....if I'm logging and I see 10.345 g/s @ 80 deg C do I go into edit and put in 10.34 @ 80 deg C? Then do the same in gear?
Another quick question...the iac airflow g/s #s I get do I just transfer those numbers right into my airflow table in LS1edit?
For example....if I'm logging and I see 10.345 g/s @ 80 deg C do I go into edit and put in 10.34 @ 80 deg C? Then do the same in gear?
no, becuase your car might want moer air that that. its just what its acutally getting. it may want more or less. have to find out what hte idle air trims are and i bet you cant wtih that software
