03 corvette with LS2 TB upgrade and harness..idle problems

[skippy]

Car is a 2003 Corvette
has a fast 102 with an LS2 TB (ETC with No IAC motor)
original TB is ETC with IAC motor

this harness is supposed to eliminate the IAC...
the problem we are having is that the car will not idle...
once it starts commanding IAC it just goes nuts..
commands differnt values for IAC desired, but doesnt see anything back(just reads that it stays pegged at 310)

should I be seeing it return info other than 310 IAC position
or did I miss something in the tune that I need to change for it
I have changed the ETC scalar to reflect the new TB size
I have brought the Idle air up to a point where it hold the idle at roughly 100ropm above desired idle until it comes to a complete stop and tries to enter into adaptive idle.

any help is greatly appreciated..

[JoeyJoeJoe]

If the original TB was stock for a 2003, it did not have an IAC, it had the tps on one side and the motor for the blade on the other. When you convert to a later style, the motor and tps wires are in one plug rather than two.

Make sure your injector data and airflow models are correct, put in the correct ETC scaler for that TB, and you should be close. Make sure you change everything back first that you tried to fix this.

Also, I dont know about the LS1/6/2 102, but I on the LS3 one the stock TB barely seals. Make sure you have it centered and are not sucking air on the top or bottom.

[Google]

etc throttle control still uses the iac effective area vs steps table and the etc scaler table..

when scanning log iac desired position in the table display to see iac function.. the pcm uses the throttle blade for iac adjustment but it is idle air control! or iac for short.. now with a cable or none etc throttle it would be correct to call it iacm or idle air control motor..


..

[skippy]

the guys who owns it was telling me it had an IAC originally....
which Is why I'm asking...

honestly... everything has been done as normal for any TB change....
but it doesnt make a difference...

[Google]

Car is a 2003 Corvette
has a fast 102 with an LS2 TB (ETC with No IAC motor)
original TB is ETC with IAC motor

this harness is supposed to eliminate the IAC...
the problem we are having is that the car will not idle...
once it starts commanding IAC it just goes nuts..
commands differnt values for IAC desired, but doesnt see anything back(just reads that it stays pegged at 310)

should I be seeing it return info other than 310 IAC position
or did I miss something in the tune that I need to change for it
I have changed the ETC scalar to reflect the new TB size
I have brought the Idle air up to a point where it hold the idle at roughly 100ropm above desired idle until it comes to a complete stop and tries to enter into adaptive idle.

any help is greatly appreciated..

need to post a log file and the tune in which was loaded at the time of the scan..

log idle desired airflow
dynamic airflow
stit
ltit
wb or trims
ect
tps
iat
rpm
iac desired position
map


...

[skippy]

sorry.. I dont have any logs of it right now.

[Google]

I see the problems but need the scan to give the correct info to change from/to..





..

[Google]

also would be a good idea for you/them to fail maf and put into sd mode to start out for tuning the idle.. when done with the basics then flip back to maf and tune maf..




..

[S2H]

I see the problems but need the scan to give the correct info to change from/to..



..

if you see the problem... then do tell...
I dont see anything wrong in the tune other than possibly a little high on the idle airflow... but that wouldnt make it surge from 400 to 1600... and not idle... it would just make it hang high until adaptive idle kicked in...

try to get a log when you can dude...

[Google]

if you see the problem... then do tell...

ve, maf, raf, iac/ etc scalar, and timing

[skippy]

also would be a good idea for you/them to fail maf and put into sd mode to start out for tuning the idle.. when done with the basics then flip back to maf and tune maf..


..

Its Already been done.
Tuned in SD, had same idle issues
Tune with MAF on, same idle issues
Idle Airflow is what its asking for in idle desired when logging
it does not hang high in rpms...well..I correct that.. hangs at about 1000~1100 untill you come to a full stop..but thats ok.
once you come to a stop and it settles in to where its supposed to be, thats where its having idle issues

[skippy]

ve, maf, raf, iac/ etc scalar, and timing

obviously you have no idea of what you are talking about...
A/F with a wideband is Dead Nuts on
and fuel trims are within 4% either way in SD...
and with the MAF they were within 2%...most of the table they are within 1% or less

ETC scalar is adjusted for the new TB size

[S2H]

the timing in the tables in that tune would not cause that issue either...

[Google]

adjust the scalar to lower desired airflow to get dynamic and desired to match more closer. this should help with idle hang.. but still would need to see the log file to see the before and after and to know if somthing else is in play causing issues..

I always run s.d. when tuning idle and when done if idle goes wacky then you know it is maf fueling or the blending of the maf and the ve table causing the problem..





..

[Google]

obviously you have no idea of what you are talking about...

ok skippy.. have fun..

[S2H]

adjust the scalar to lower desired airflow to get dynamic and desired to match more closer. this should help with idle hang.. but still would need to see the log file to see the before and after and to know if somthing else is in play causing issues..

I always run s.d. when tuning idle and when done if idle goes wacky then you know it is maf fueling or the blending of the maf and the ve table causing the problem..

..

wow... did you not read....
does it in both MAF and SD
its not an interaction between the two

you dont push the scalar till they line up.
you put in the right value for the size of TB...
simple math.. area of a circle...
looks like the change of a 78 to a 90....
which would be right for an ls2 TB

[JoeyJoeJoe]

Google: I was trying to say that it does not have an actual IAC motor, not that he has no IAC control. In case he tries to replace the IAC, I dont want him to get embaressed at the parts counter.

Soundengineer: Is that Oregon Trail? Dont remeber the ninjas on the Apple IIe version.

To the OP, I have learned a ton from both Google and Soundengineer, even though they might not always agree, they both give a lot of good info.

[lsxrx7]

Has anyone actually looked at the ve table?

[S2H]

obviously you have no idea of what you are talking about...
A/F with a wideband is Dead Nuts on
and fuel trims are within 4% either way in SD...
and with the MAF they were within 2%...most of the table they are within 1% or less

ETC scalar is adjusted for the new TB size

He says SD and MAF are tuned right here in this quote