a friend of mines car has gutted cats and was throwing codes, he needs inspection so we bought sims.

we were told to put them in the front 02 sensors.............big mistake!!!!! car misfired wouldn't run etc.

we put them in the back 02 sensors, went to autozone to have the codes cleared out..............and he failed inspection for the catalytic converter code!!

now we put the sims on, went to atuozone, and had it inspected all in one day. does the computer have to go into a new loop or do we have a bad sim

 

1. 02 sims go in the rear, other wise the car has no way to tell if it's running rich or lean and will go into limp mode.

2. After restting the computer/clearing the codes you usually have to cycle something like 20 times engine on/off to make the computer happy. It runs some of the self-smog test 15-20 cycles before is passes itself. This is why you cannot just re-flash your computer and head down to inspection, you have to plan ahead a bit. A program like Auto-tap can tell you when the self tests are complete. If you were throwing codes still then you may have a bad O2.

Did you reset the computer to clear the codes? Disconnect battery or pull a fuse? How was it done?

 

When I first got my car it had sims on it. It would periodically throw codes. It didn't affect how it ran, but I got sick of it and disconnecter the battery one night and left it disconnected all night. The next morning I connected it back up and started the car up. It didn't want to idle but I guess the have to learn it or something when you reset the computer. Anyway, it hasn't thrown a code up since and that was 5 mo. ago.(fingers crossed)

 

When I had new headers put in they were longer that the originals so they came with extensions. Well, one kept throwing out a bad code. Found out it was connected backwards. The prongs matched four on each side ( I think), but just backwards. Lined them up properly and all was well. If it becomes a prob with emissions I had a guy turn off my code with Auto tap in the mean time.