Hello all, need to replace old catalytic converter, Any recommendations? When replacing cat do I / should I replace O2 sensors?

Olaf

 

Did you repair any condition that may have harmed the catalytic converter? Misfires..ect

 

Hello oilcanhenry,
So far we have only replaced the plugs ( ACP 41-101 ) and wires ( DEN 671-6259 ) and cleared P0420 code, New to us ( 4 weeks ) 2007 Equinox @ 98000. Old plugs were bad and it had been misfiring. With the new plugs and wires the engine is now running like it should. However it looks like the damage has been done and we will need to replace the catalytic converter. I was thinking I would try replacing O2 sensors first, but that would have been to easy. Equinox is for my 17 year old daughter, her first car.
ole

 

You could try cataclean,sold at all parts stores,cleans them up and o2s also,20$

 

Oh boy did I get lucky, purchased a new WALKER 54526 cat for the Equinox, $140.00. Should I replace the old O2 sensors?
Is there a way to test EGR valve?

 

I'd replace the cat first and see if the P0420 code goes away. You're not out anything by trying this first. The EGR valve can't be easily tested in a manner that can accurately confirm if it is good or bad. If you aren't getting any EGR-related codes (P0403, P0404, P0405), don't worry about it.

Just a side note, the EGR valve on our Equinox looks like it will need to be replaced again. The AC Delco replacement lasted about 7.5 years and 130K miles. The OEM part by comparison lasted about 5 years and 60K miles. We recently started randomly seeing the STABILITRAK DISABLED & SERVICE TRACTION CONTROL messages again with a check engine light coming on a couple hundred miles later. Sure enough, my scantool found the familiar P0405 and C0561 codes (both were confirmed; not pending), but no P1779 this time.

Just for grins I monitored the realtime data (specifically EGR command % and EGR error %) with my scantool while driving on the highway for a few miles. The latter jumps around quite a bit, but is consistently near 100%.

 

New cat is in (Walker 54526) and its been 3 days, P0420 code is back again, just cant seem to get rid of it, is replacing downstream 02 sensor my
next move?
Need help someone.

 

Yes, replacing the downstream oxygen sensor is the next step. I recommend AC Delco or Denso oxygen sensors. Do NOT use Bosch oxygen sensors. They are garbage.

 

It's fixed, Been 3 weeks now and no check engine. it was the downstream O2 sensor, replaced with new A C Delco.

 

Glad to hear you got it fixed. Thank you for following up and posting your solution.

I have also replaced my EGR valve since my last post. All the symptoms and codes have gone away.