Hi everyone, I just replaced the O2 sensor on my 88 GTA.
It now idles MUCH better, but still throws code 13 when cruising at highway speed.

Any ideas?

 

Unplug battery to reset?

 

I unplugged the battery and it took much longer for the check engine light to come on, but it still did after a while.

 

I had this problem and could not get the code to go away to save my life, it bothered me so much, finally I got some info on tgo and was told to check my ecu, found out for some reason the purple wire not sure on the number had loosened plugged it back in gone. I went through 3 02 sensors.

 

Yeah, it was running very nicely when I first changed it.. but now it feels like the o2 sensor is going bad again.
The ECU is on the passenger side right?

If anyone else has any ideas, please chime in!

(I saw this if it helps my issue: http://www.chevythunder.com/o2_sensor_diagnostics.htm)

 

yes right under the dash very east to get to

 

it was running nicely because you cleared the ECM (trouble code) when you disconnected the battery not because you replaced the sensor. Open loop does not need O2 data.

after some run time when it reached closed loop the ECM could not "see" the sensor so it threw the code and defaulted back to "limp home mode".

Check the O2 sensor wiring for damage, sometimes the end gets burned up by the exhaust heat. sometimes the wire comes loose or gets scraped under the dash..

The real problem is most likely a short between the ECM and the sensor, the error code just tells you where to look.

 

Ok, I'll follow the cable to under the dash and report back with my findings!

 

Rock auto has new ecm for 80$, sounds like you might have computer issue or a short somewhere on the line maybe...get scanner tool and check your ecm..i just ordered a cable to check my ecm,this cable which plugs into your aldl (the black under your drivers side dash to the right) and goes from there into your laptop can run on free a program like tuner pro and get a general diganostic on everything..looks like its gonna be the shizz...you should be able to get a reading on the voltage of your o2 sensor on that program and see if your in fact getting voltage to it and if the voltage is correct

 

That'd be an awesome idea, where did you order your cable from?
I have a laptop I could put the software on and scan the car's ecm.

EDIT: after some searching around the site, I just ordered one as well!

 

um< that's NOT a new ECM from rock auto. its a POS from A1 cardone in disguise!!

 

Also, check for shorts or opens along the GROUND wire for the O2 sensor. I had the same issue and found a splice to the wire on the ECM connector. On my `89 with TPI, it was a tan wire that grounds to the back of the engine on the passenger side head. I repaired the splice and the problem was solved! Remove the panel under the passenger side and trace the wire as necessary. You could also have a corroded/loose/poor connector to the sensor itself. You can buy and splice in a new connector, if needed.