Originally Posted by Double_v23
Stop making guesses....You aren't listening to what the people here are telling you. The removal of the cats WILL NOT make the car run rich or lean. The only thing it will do is cause the check engine light to come on when the system runs a catalyst efficiency test. IF the car is before 1996 then this doesn't matter because OBDI does not check catalyst efficiency.
The reason that you have no activity on the O2 sensor is because your system is too rich or too lean for the computer to compensate. The O2 sensors don't send a signal if the fuel mixture is too far off. They will stay maxed out lean or maxed out rich. Or it could be a wiring problem.
CUSTOM TUNING!?! You have 2 bolt on parts (wasted money) and no cats there is no reason that the computer shouldn't be able to handle these "mods".
You need to look at the datastream....find the 02 sensors on the screen and see what they have for voltage. If it is close to 0 mv (millivolts) then your system is too lean) if it is close to 999 mv then it is too rich.
Causes of a lean condition could include...
-stuck closed injector
-vacuum leak (probably under that P.O.S. spacer)
Causes of a rich condition could include....
-stuck open or leaky injector
-fuel in the oil
-too much fuel pressure
-restricted air intake (clogged filter)
Take it to someone who is certified to be working on this stuff. And remember that there is no certification that includes the word "tuner"
thanks useful info
car is a 99 ls1 trans am the ppl who custom tune engines down here really know their stuff they even tune for ppl out of the u.s... codes also come out that theirs no coolant thats why am asking if the line thats deleted might be causing the check engine light to turn on besides the 02 sensor i already fixed one problem car had i changed the pcv valve it was clogged and engine was kind of full of oil threw outside of the engine car got lots of throttle response and power right after i fixed this
also the mods the car has were already on there when i bought the car