MOSTDELUXE

iTrader: (3)

I have ls1 edit and was wondering if anyone can tell me what to change to stop the idle problem. The car was tuned with a different combo since then i changed the cam and map sensor and now the car does this. PLEASE DONT TELL ME ITS A VACUME LEAK! it was tuned to do this with the old cam i just dont know what to change. the car idles perfect in p,n, and drive but as soon as you start rolling it raises iam guessing the speed sensor in the trans tells the computer the car is moving?

Frost

iTrader: (45)

start with the basics, get the IAC to 60 counts at hot idle. Your RAF is probably too high though.

VinceTrifecta

If the basics check out, take a look at your throttle cracker/follower table values.

MOSTDELUXE

iTrader: (3)

ive been looking at the throttle cracker but dont know what the numbers mean? or wich way to go

edcmat-l1

iTrader: (10)

Yep....
Dont know LS1 edit, so cant clue you in. But, it def sounds like it has been over-compensated for in the throttle cracker/follower tables.

MOSTDELUXE

iTrader: (3)

Can anyone explain what the throttle cracker does and what the numbers are in the tables.

Frost

iTrader: (45)

the numbers are additional airflow... this table offsets the IAC. Personally, when I tune a car, I set the whole table at 0 and add 1.5g to the 400 RPM column everywhere except the 0 MPH row. This is just used to help catch things if it ever dips this low. If your base running airflow table is correct, I'm not sure why this table would really be needed in most cases.

ringram

Helps smooth out gear changes and driveline transitions in my experience.

P Mack

iTrader: (6)

I agree. I also zerod mine out because i like the rpms to fall faster so I don't have to wait between shifts. 99% of the time high idle problems are related to the idle airflow table, not the throttle cracker.

The reason people usually think it's the throttle cracker is because the car stops adjusting the IAC to keep idle rpm when you cross the throttle cracker threshold (when you start moving). It makes sense, the idle trims shouldn't learn if the throttle cracker is messing with IAC position. But the root problem is not the throttle cracker value, it's the idle airflow value.

zmonsterjb

iTrader: (16)

how do you determine if your Iac counts are to high?
Raf and Iac are they the same?

Rhino79

iTrader: (7)

Use a scan tool for the IAC, see what the counts or steps are. If they are above 60ish then use the set screw to open the throttle blade a bit, reset the tps, and monitor steps again. RAF is the base aiflow table in the PCM, the IAC is the mechanical part that executes all the RAF, throttle caracker/follower functions.

zmonsterjb

iTrader: (16)

what all do you want to scan
when checking for this issue?