98Redta

guys, i have Pacesetter headers into straight pipes all the way out the back with 2 single chamber flowmasters on my car, no cats. I put o2 sims on it to try to get it to run right and it still throws the ses light and feels as if it misses. I hooked it up and its throwing all kinds of 02 sensor codes, no activity, and something dealing with heat, mainly thoses two. Should I throw some cats back on and put my sensors on or do I have a pair of crappy o2 sims?

eallanboggs

iTrader: (1)

It's probably NOT the O2 Simms fault. The O2 Simms merely generate a DC square wave output that oscillates above and below 450mV. I think it has to do this at 3 times per second to satisfy the PCM. When I checked mine with Auto Tap it was transitioning between 350 and 700mV. Some O2s have heaters and other do not. I believe if the O2 has 4 wires coming out of it 2 are for the O2 sensor output and the other 2 are the heater circuit. If yours have only two wires it could be that your O2s are now mounted to far back in the header pipe to get hot enough to function properly. Some people have had to weld a bung closer to the front of the header to get their O2s to work properly. You may have to do the same. If they have four wire the heater circuit if malfunctioning.

BAT TA

iTrader: (15)

You do have your front O2s hooked up don't you?

blkZ28spt

Even if the O2 sims didn't do anything it should still run perfectly fine.

Just to double check, you do have regular O2's hooked up for the first pair right? If your o2's end up being shot, I recommend NOT getting Bosch units. I put bosch part #13111 on mine when my O2's went out, had the car tuned again at speed inc and they put GM parts back on...they said that with the bosch units the fuel trims were all over the place.

98Redta

Thanks for all the help guys!