Installed LT's, ORY, and !CAT a few days ago and I can't get my car to do what I want it to do. It's backfiring and at first I thought it was because it cooked a wire and was arching onto the header, I fixed that problem. Went back and twist tied everything I could find away from any metal. At night I don't see any sparks flying anywhere, yet it still backfires. It typically only backfires while in gear and driving around, reving it in park or nuetral it usually doesn't backfire. My driver side header does NOT have the A.I.R. hooked up because I need to get my hands on a fitting, however I blocked it off temporarily. I don't think that would cause any of this but I'm throwing it out there to give you guys some more info.

When I floor it I got black smoke coming out the pipes, and you can smell the fuel just walking around the car. So it's definitely running rich.

Also hooked up my scanner because I have loss of power, the car is pulling between 8-11 degrees in timing only when in gear. In park there is no timing being pulled at any rpm. I believe my y pipe is hitting the frame, could this cause the knock sensor to pick up false knock?

I really need help troubleshooting so I would really appreciate any advice.

 

Do a board search for knock sensor.

Put the knock sensor on a switch with one side stock and the other on a resistor.
If ya KNOW ya got false knock then just put it on the resistor.

ANY unusual noise will pull timing,even the internal sound of your headers.

 

Backfiring could be from crossed wires.

 

yes id check the wires again and c if u ran them correctly. the cylinders dont correlate with the opti, meanng they dont run in exact order.

also it could be u getting false knock , id either do the resistor mod or just get u an lt4 knock module


either way , everybody else is on the right track

also check for header leaks. or leaks b4 the o2s

 

Crossed wires..

 

Tonight I'll get it back up on the lift and check if my wires are in the right order. My MSD cap and rotor has numbers for which wires go to which cylinders so I'll just follow that for a guideline.

Thanks guys I'll get back to you with an update.

Edit: Also forgot to add in, I get knock retard with the AC or Heat on. Only a few degrees however not nearly as bad as when in drive.