pinhead73

I recently installed a set of ebay long tube headers and y pipe with some new (off brand) oxygen sensors. I am now getting codes 13 and 63 with a service engine soon light and my gas mileage dropped from about 28mpg to 15 or lower. I have checked the plugs and they are plugged in. None of the wires are burnt or melted. Is there anywhere else that I should check? Should I just get a set of AC Delco oxygen sensors?

Injuneer

Both codes are for an open circuit. The PCM determines this when it sees a steady sensor voltage in the range of 350 - 550 mV. This can happen due to the sensors not warming up enough to work (600*F).

Did you use 4-wire heated sensors? The heater circuits get power from fuse #11 in the under hood panel. Make sure you have 12V at the brown wire in the O2 sensor harness connector. Harness off the sensor connector, measure the resistance on the heater wires.... stock is black and pink, but who knows if your replacements have the same colors. Resistance should be 3.5 ohms at 68*F and 14 ohms at 622*F.

Do you have an old sensor you can try?

pinhead73

I have the 4 wire sensors. I will check the #11 fuse in the morning and check the wires to see if they are getting power. I do have the old sensors. One came off easily, the other (the one in the manifold) is fighting me. I will see if it will come off with some more pb blaster. I have noticed that the code when erased doesn't come up immediately. It takes several miles for it to pop up with the ses light.

Thanks for the help. I will let you know what I find.

Injuneer

You only need to swap in one old sensor to see if it deletes the code for that bank.

The PCM can't run the diagnostic until certain conditions are met. Has to ignore the static readings that set the code at least until the timer for going into closed loop times out (typically 206 seconds). There are others like "throttle position greater than X%", but I would have to have my factory manual in front of me to remember the details.

pinhead73

Problem solved. It was the cheap sensors I bought. I replaced them with a set of ac delco o2 sensors and the problem was fixed.

Injuneer

Good to hear you sorted it out.