Could use few tips on removing my o2 sensors

[killertiller]

I have a 2002 dohc taurus and i think my third cat converter is shot. SO i want to remove the 2 o2 sensors and see if it gets better so i can figure out if its that cat. What size iws the o2 sensor and shud u buy the socket or can i use a open end wrench. Thanks guys

[pawpaw]

Most autoparts stores have an O2 sensor removal kit in their "Loan-A-Tool" program, for a refundable deposit, so no need to buy a special socket. This kit has all sorts of socket types/configurations. DON'T try using an open end wrench if its stuck, as you can round off the hex & Really cause yourself problems.

If you don't want to mess with removing an O2 sensor to relieve back pressure from a suspected blocked cat converter, use your vacuum gauge to do the scenario 14, blocked exhaust test here http://www.secondchancegarage.com/public/186.cfm

Some thoughts for pondering, let us know how it goes.

[downhill]

I have had the best luck with a crows foot on an 6 in extension. The most important is to soak with penetrating oil before attempting to remove. I soak a few times and days before removal attempt. Go slow and do not break them. Pawpaw has it right with the vacuum test.
Vacuum gage is one of the best and easiest to use for many engine health test.
Good luck~

[killertiller]

Will it test the third cat or does it test whole system. I just thinking my thirrd cat is the problem

[pawpaw]

Originally Posted by killertiller

Will it test the third cat or does it test whole system. I just thinking my thirrd cat is the problem

It tests the entire system. Removing the before cat/upstream O2 sensor does the same thing. Removing the after cat O2 sensor only checks things after the cats.

Do you have a lit CEL/SES light & trouble code for the suspect cat converter???

[sheila]

Fwiw, o2 sensors require 22mm (7/8") wrench or socket to remove. You want to check scenario#14 in pawpaw's link.

[killertiller]

No check engine lite thats why i think its third cat. Car was real bad n had like no power, top speed of like 25. Then something blew out i feel n it was perfect for few days. Now slowly but surely its loosing power. I have driven it about 700 miles like this n no check engine light ever. Another guy had same exact problem and ended up bein third cat.

[sfhess]

Unplug the o2 sensor connector and use a box wrench if you can get to it.

[pawpaw]

Originally Posted by killertiller

No check engine lite thats why i think its third cat. Car was real bad n had like no power, top speed of like 25. Then something blew out i feel n it was perfect for few days. Now slowly but surely its loosing power. I have driven it about 700 miles like this n no check engine light ever. Another guy had same exact problem and ended up bein third cat.

If your cat converter isn't working, you should have a lit CEL/SES light, so does the trouble light come on for its self test at KOEO before you crank the engine????

If the CEL/SES lamp lights up for its self test, maybe you have a loose baffle/blocked muffler problem????

[killertiller]

Ya engine lite works fine. I just had to fix few items when i got car. I had lite on and use diagnostic tool to get codes. Now i even checked the codes and nothing. No lite no codes. Cars getting like less then 15 mpg.

Originally Posted by pawpaw

If your cat converter isn't working, you should have a lit CEL/SES light, so does the trouble light come on for its self test at KOEO before you crank the engine????

If the CEL/SES lamp lights up for its self test, maybe you have a loose baffle/blocked muffler problem????