what would keep IAC values from going down when going 25 mph and up?
09-09-2005, 06:58 PM
#1
what would keep IAC values from going down when going 25 mph and up? well my rpms will hang at 1500-1800 if im going over 25 mph and throw the clutch in. my stit and ltit are also falsely staying at +0.50 when added together which once i come to idle they start to go negative after i let it sit. when my fan 2 comes on the idle air trims will go way + on me so i assume i have to add more idle airflow for fan 2 right?
i just dont understand. using the vcm controls if i shut the iac motor down to about 85 the rpms come down with no problem. but the iac count seems to hang stable. any ideas where to look? im going to look at incraseing the decay in those speed cells to get it down more, but then again i dont know if its just commanding too much air when moving like that or what? i have my baffles out of my hood so i dont nkow if that airflow it sees can contribute and make the iac motor want to stay open, for some reason.
i also would like to keep these damn idle air trims from learning those shitty numbers. also my hot idle airflow is right on. if i turned the fans off the idle would still hang up, but the trims like i said still for some reason stayed at +0.50. i just dont know if those false numbers could report back to open the iac more?
i just dont understand. using the vcm controls if i shut the iac motor down to about 85 the rpms come down with no problem. but the iac count seems to hang stable. any ideas where to look? im going to look at incraseing the decay in those speed cells to get it down more, but then again i dont know if its just commanding too much air when moving like that or what? i have my baffles out of my hood so i dont nkow if that airflow it sees can contribute and make the iac motor want to stay open, for some reason.
i also would like to keep these damn idle air trims from learning those shitty numbers. also my hot idle airflow is right on. if i turned the fans off the idle would still hang up, but the trims like i said still for some reason stayed at +0.50. i just dont know if those false numbers could report back to open the iac more?
09-11-2005, 08:14 PM
#4
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Originally Posted by WS6FirebirdTA00
throttle cracker airflow adds airflow at speed right? it looks like where the stock table went to 3.0 is right at the limit where my rpms were too high so ill try to lower that to be in sync with the rest of the table
09-11-2005, 09:34 PM
#5
it was the throttle cracker airflow. the stock table sets it at 3 g/sec and the rest of the table is about 1.1 or so. i put it to 1.25 but it doesnt come down as nice as id like so i set it even lower. this way comming to stops and what not the rpms wont be as high
09-11-2005, 10:03 PM
#6
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I was thinking the same thing. Mine hovers around 1800-2000 rpms when off the gas from 25-40 or so. I set my throttle cracker to enable at 10mph and disable at 9mph to eliminate the surging when backing up slowly. When I come to a stop, it idles down extremely quick though. I need to make some tweeks and find a happy medium...
09-11-2005, 10:10 PM
#7
try to just cut the airflow values in half and see if that helps. that brings up a good point though i wonder if this will help some part throttle surging under about 10 mph...maybe cutting some values back. i know they are at about 0.20 g/sec to about 0.50 g/sec in those areas
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u gonna come out thurs night? i hope they want to go to sonic, we dont need to go by the speedway.
09-13-2005, 10:43 PM
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I'm using EFI live. I'm also finally getting the hanging idle problem worked out.
I've reduced the stock throttle cracker table to about 1/3 the flow of the stock table. I moved the IAC effective area table now 6 places to the right. Because my Tbody is drilled and cracked open a bit to bring IAC counts down. this has had the best effect. the more you move the table right, the more air the computer knows is already passing through the Tbody at 0 IAC steps.
And my idle airflow numbers have been brought down considerably from where I initially started tuning.
Still, I have variations. Like some mornings it will be great. Let off the gas push in the clutch and it will settle perfectly down to 1000 or so rpms with AC on or off. Then at other times it will hang higher at 1200 or so with AC on, but nicely at 1000 with it off? It may be IAT related. Any thoughts on that?
I'm gonna try reducing the high limit of idle correction with AC on and see if it does anything.
I've reduced the stock throttle cracker table to about 1/3 the flow of the stock table. I moved the IAC effective area table now 6 places to the right. Because my Tbody is drilled and cracked open a bit to bring IAC counts down. this has had the best effect. the more you move the table right, the more air the computer knows is already passing through the Tbody at 0 IAC steps.
And my idle airflow numbers have been brought down considerably from where I initially started tuning.
Still, I have variations. Like some mornings it will be great. Let off the gas push in the clutch and it will settle perfectly down to 1000 or so rpms with AC on or off. Then at other times it will hang higher at 1200 or so with AC on, but nicely at 1000 with it off? It may be IAT related. Any thoughts on that?
I'm gonna try reducing the high limit of idle correction with AC on and see if it does anything.