Hey guys,
Is this parameter exposed in HPT? I did the 24X 0411 swap onto my '96 LT1 and would like to change this number from the LS1 365 to the LT1 160.
Thanks,
Jason
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Hey guys,
Is this parameter exposed in HPT? I did the 24X 0411 swap onto my '96 LT1 and would like to change this number from the LS1 365 to the LT1 160.
Thanks,
Jason
My LT1 uses up to 310 without issues.
Cool. Thanks Ben. I assume that you're actually seeing an increase in airflow above the 160 step number?
Jason
I tried to control the IAC with the bi directional part of the scanner, to see if there is in fact an increase in airflow above 160. BUT, the scanner only allows you to command 127 counts. WHY????
Jason
Bidirectional controls can only allow so much, it's not HPTuners, it's GM.
Thanks Mike. Seems like a leftover from some earlier PCM...
Jason
No, seems like binary math...0 through 127 is 128...2*2*2*2*2*2*2=128.
More than 1 way to skin the cat Mike :-) Happy Holidays....
Good point guys. Being a MECHANICAL engineer, I don't usually think in binary or hex....
Any help on how I can figure out how many steps the LT1 IAC hardware actually will execute?
Thanks,
Jason
Was just thinking about this again on the way home... I think I figured out how to test the LT1 style IAC for max counts. Create a tune that requests idle to increase from 2500-4000 with increasing temp. Get the engine nice and warm on the "normal" tune. Then upload the test tune. Watch the IAC counts to see where the RPM stop increasing with commanded IAC steps.
Will try this tomorrow out in the middle of no where so I don't have my neighbors calling the cops ;)
Jason
Tried my idea this morning. No dice. PCM will only command up to 1200 rpm idle. HPT will let you put 8000 in the table but the sets anything over 1200 to 1200. So thinking I need to try something with the throttle follower / cracker tables to get the airflow up since I can't raise the idle.
Jason
OK, finally got the smoking gun. See the attached log files. Make sure you are looking at the following:
MAF
idle base sum airflow
IAC pos
IAC desired pos
Attachment 48579
Attachment 48580
IAC Log 001
I used the idle air table to add air with engine temp. So the IAC gradually goes up and the actual MAF airflow does not.
I also used the throttle cracker to add a ton of air. So you can see when I blip the throttle, the IAC goes to 310. The airflow does not increase, and as the IAC decays, it still is around 1.8 lb/min max which is about what you get with IAC = 200.
IAC log 002
Here I manually turn on the fans so the engine temp drops and the desired idle air flow increases as the engine temp goes down. The MAF reading goes up, but only until about 200 IAC counts.
So from these two logs, it appears that the L98/LT1 style IAC does not go to 310.
How can I request access to this parameter with HP Tuner? I can see it in TunerPRO.
Jason
Find a file in Tunerpro that you can change it in (I think the only definition that will work is a 2001 os). Change it and nothing else, and send support both files explaining what you did and asking them for access to it in your is.
I couldn't find any contact info for support. So I started a thread here:
http://www.hptuners.com/forum/showth...-2001-0411-PCM
Is that the correct process?
Those of you with LT1 24X conversions may want to express your support.
Thanks,
Jason
E-mail "[email protected]"
Sounds to me like the iac port in your tb is limited to x airflow. The other thing is why do you need that high of iac count anyway?
Will do. Thanks Mike.
Flame, the LT1 TB is completely different. Flow volume and IAC motor. I just want to be able to set the max steps value in the PCM so it doesn't keep trying add steps that just don't happen.
I'm still trying to figure out how to re-map the flow volume per IAC step:
http://www.hptuners.com/forum/showth...uning-IAC-area
Thanks,
Jason