01-30-2012, 01:10 PM
Anybody ever get the service engine soon light from a ported throttlebody? The code shows a high rpm's at idle. I know one other guy with a LS1 Z28, who said he was getting a code thrown from is ported tb, so he just put the stock one back in. Is this common for that mod? The rpm's don't exactly seem to be higher, but is this something to worry about?
01-30-2012, 01:47 PM
It's not common..It might be your sensor
01-30-2012, 01:51 PM
If you over-hog the throat, you can get enough bypass
air at closed throttle that the IAC loses authority over
idle RPM, and then the PCM will bitch about it. Ditto for
overdrilling the hole.
But it could also be too-snug cables, a jacked stop-screw,
etc. First thing, pull the TB and look for daylight around
the seating circle of the butterfly and whether the stop
screw can be backed out any.
Then you will have to wait for it to get its mind right
about the new closed-position airflow and get back the
idle trims, but that's just time on the driveway and a
few key-on cycles.
But people get impatient and just have to mess with
the metal instead.