Oxygen Sensor

[RayRay]

Any updates on the potentially stripped O2 sensor, Fudge? I'm about to do the same thing...having a really hard time diagnosing a no-start problem. Thinking I should replace the O2 as a matter of principle. Don't really wanna buy a new exhaust manifold in the process though ;-)

[Rick the Quick]

Soak 'er down good with PB Blaster. Let 'er sit overnight.
Put the appropriate size 6 point socket with breaker bar on it and hammer on the breaker bar. A good copper Thor hammer is good to use. The idea is the blows from the hammer will break it loose. This has always worked for me. I would not worry about the connector because these are single wire sensors and they can easily be spliced, soldered and taped. I know this is not the so called right way to do it but it has worked well for me.
Good luck!

[ricko1966]

Any updates on the potentially stripped O2 sensor, Fudge? I'm about to do the same thing...having a really hard time diagnosing a no-start problem. Thinking I should replace the O2 as a matter of principle. Don't really wanna buy a new exhaust manifold in the process though ;-)

o2 sensor is a way too over replaced part. Super easy to test before replacing. Dsconnect the o2 sensor put a meter on it.Create a vacuum leak to drive it lean while cwatching your meter. Spray some propane in the intake drive it rich,look at your meter.Not sure about your results put the sensor on the bench put a meter on it heat it with a prpoane torch look at your meter. I do not remember the values IIRC it is0-1 volt could be 0-1.5 volts and the meter should rise and fall fairly rapidly as in you don't need to watch it for a minute slow respone it is getting lazy. no responxse. We all know what that means

[fudge]

I got my engine swapped, never did get that sensor out haha. Good luck

[RayRay]

Rick the Quick - sincere thanks for the tips. Understand what you mean about the "right" way. I've often found the "second right answer" when the first right answer wasn't applicable. ;-)

Ricko1966 - Appreciate the knowledge!! Bookmarked for future use. Haynes manual refers to back probing to test the oxygen sensor, but didn't include your real-world testing. Only problem I have is the engine isn't starting, so I can't test it. Prolly gonna start a new "help me" thread since there's a lot going wrong and I'm hitting numerous dead ends (likely bc I'm looking in the wrong places, but hey, I'm trying)

Fudge - Thx for the luck. Figure I'll use mapp gas to warm up the exhaust manifold before attempting the removal. Or, like you, maybe swap the entire engine! (ha) ;-)

[firebush357]

Any updates on the potentially stripped O2 sensor, Fudge? I'm about to do the same thing...having a really hard time diagnosing a no-start problem. Thinking I should replace the O2 as a matter of principle. Don't really wanna buy a new exhaust manifold in the process though ;-)

I took the Manifold off and Sprayed PB Blaster inside the O2 sensor bung so that it could sit for a day or too and seep down into there then spray PB Blaster on the outside every couple of hours. Bolted it back to the Manifold and used a wrench to get it off because I didn't have a deep well socket at the time. If you have a Torch then that might help as well.

[ryanprins13]

Any updates on the potentially stripped O2 sensor, Fudge? I'm about to do the same thing...having a really hard time diagnosing a no-start problem. Thinking I should replace the O2 as a matter of principle. Don't really wanna buy a new exhaust manifold in the process though ;-)

A festiva will start with a bad 02 sensor or no 02 sensor or an unplugged one. Something else is wrong.
If you want to remove it look at what i said in post #7. My cel came on for it once, bought a new one which dropped my fuel milage by 10mpg. Went to the junk yard and got a used one. Since then i have pulled almost every 02 sensor ive seen in the junkyard, probably have 10 or 15 spares. Every time i remove the grille, cut the plug so the box end of the wrench fits over, put wrench on and start heaving. Never broke one although i was sure i would every time. They still plug in fine after if you only trim the mimimum plastic off to fit the wrench.
No heat or penetrating fluid on any of the jy cars although i do on mine still for some reason though [emoji14]

o2 sensor is a way too over replaced part. Super easy to test before replacing. Dsconnect the o2 sensor put a meter on it.Create a vacuum leak to drive it lean while cwatching your meter. Spray some propane in the intake drive it rich,look at your meter.Not sure about your results put the sensor on the bench put a meter on it heat it with a prpoane torch look at your meter. I do not remember the values IIRC it is0-1 volt could be 0-1.5 volts and the meter should rise and fall fairly rapidly as in you don't need to watch it for a minute slow respone it is getting lazy. no responxse. We all know what that means

Just to add to this- Cel seems to come on pretty quick if the 02 leans you out too much, and of course comes on if it actually quits. However it doesnt when the 02 runs you rich. Like i said above, i bought a new universal 4 wire one that supposedly worked for my car. Dropped me 10 or more mpg with no cel. Used oem one fixed that straight away.

With your testing ricko- you can do it with the car stationary revving the engine right?

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[ryanprins13]

Also your car runs in open loop till the O2 sensor gets hot enough to start functioning. I think its about 3 miles at highway speed. My cel always came on going around the exact same bend in the road when my o2 sensor went bad

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[ricko1966]

In the driveway or on the bench. Sorry neglected to mention you gotta get it hot first drive it 5 miles then test it in the driveway, Make it rich make it lean does your o2 sensor correct for your rich lean conditions? Can't drive it and get it hot just put a meter on it watch the meter as you heat the sensor with a propane torch. Cool,hot,cool,hot watch the meter. Customers get mad,service writers get mad when you replace parts that aren't really bad so I try to figure out a way,the fastest way to test everything.

[RayRay]

I took the Manifold off and Sprayed PB Blaster inside the O2 sensor bung so that it could sit for a day or too and seep down into there then spray PB Blaster on the outside every couple of hours. Bolted it back to the Manifold and used a wrench to get it off because I didn't have a deep well socket at the time. If you have a Torch then that might help as well.

Another fine suggestion! Adding this to the wealth of info gathered from the site :-)

Also your car runs in open loop till the O2 sensor gets hot enough to start functioning. I think its about 3 miles at highway speed. My cel always came on going around the exact same bend in the road when my o2 sensor went bad

Another fine point, and appreciate what you said about it starting even with a bad o2 sensor. I must have another issue at hand. Already sourced a used VAF, thinking that was the problem...came from a low mileage car which looked far better under the hood than mine (although, admittedly, it was a non-runner) to no avail.

Seemed like a good idea at the time.:banghead:

[RayRay]

In the driveway or on the bench. Sorry neglected to mention you gotta get it hot first drive it 5 miles then test it in the driveway, Make it rich make it lean does your o2 sensor correct for your rich lean conditions? Can't drive it and get it hot just put a meter on it watch the meter as you heat the sensor with a propane torch. Cool,hot,cool,hot watch the meter. Customers get mad,service writers get mad when you replace parts that aren't really bad so I try to figure out a way,the fastest way to test everything.

I take it having the key on (engine not running ((since mine won't start)), but key in "on" position) will provide voltage to the o2 sensor, and then use the voltmeter to watch for the ~1 volt swing as heat is applied (and then as it cools down)? That sound right?

[ryanprins13]

I must have another issue at hand. Already sourced a used VAF, thinking that was the problem...came from a low mileage car which looked far better under the hood than mine (although, admittedly, it was a non-runner) to no avail.

Seemed like a good idea at the time.:banghead:

You should start another thread about that, get some help and get it running!

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[ricko1966]

I take it having the key on (engine not running ((since mine won't start)), but key in "on" position) will provide voltage to the o2 sensor, and then use the voltmeter to watch for the ~1 volt swing as heat is applied (and then as it cools down)? That sound right?

no. Bench testing an o2 sensor requires no vehicle, the o2 sensor produces voltage hook a volt meter positive lead to the lead from the o2 sensor, ground the negative meter lead to the o2 sensor body, heat the o2 sensor end with a propane torch and watch your meter it should go up as you apply heat come down as it cools go back up as you apply heat.The o2 sensor isn't keeping your car from running take out 1 spark plug and ground it's body,take a dish soap bottle and fill it with gas,pull the pcv hose off the side of the manifold squirt in a tablespoon of gas put the hose back on. Have a buddy watch the plug. Get in the car floor it and crank it. If it starts you have a fuel problem If it doesn't start did your buddy see the plug sparking, Air.Fuel.Compression and spark make an engine run yes it all has to happen at the right time but first lets see if we can find what's missing.Save the gas and dish soap bottle for future use and parts cleaning.

[WmWatt]

note: a torch can be used to burn off the deposits on the working end of an O2 sensor and restore it. I did this with a freind's sensor after reading how to do it on the Internet. We used a VOM with the torch to check that is was working again.

[RayRay]

You should start another thread about that, get some help and get it running!

Methinks yer right. I've noticed plenty of threads where the OP is a little, shall we say, unable to be helped ("My car feels funny on the road, please help, and in an unrelated matter, why are my tires always flat on the bottom but not the top, I try to only drive on the inflated part at the top!?")...and it tends to get on the nerves of the folks who've been on the site for a long time (and, honestly, it's understandable at times). Doing my best not to post a "help me" thread, only to find out my problem was basic and something which should have been checked in the first place.

no. Bench testing an o2 sensor requires no vehicle, the o2 sensor produces voltage hook a volt meter positive lead to the lead from the o2 sensor, ground the negative meter lead to the o2 sensor body, heat the o2 sensor end with a propane torch and watch your meter it should go up as you apply heat come down as it cools go back up as you apply heat.The o2 sensor isn't keeping your car from running take out 1 spark plug and ground it's body,take a dish soap bottle and fill it with gas,pull the pcv hose off the side of the manifold squirt in a tablespoon of gas put the hose back on. Have a buddy watch the plug. Get in the car floor it and crank it. If it starts you have a fuel problem If it doesn't start did your buddy see the plug sparking, Air.Fuel.Compression and spark make an engine run yes it all has to happen at the right time but first lets see if we can find what's missing.Save the gas and dish soap bottle for future use and parts cleaning.

Boy am I glad I asked! Didn't realize it created its own voltage! I'da messed up the test big time. Sincere Thanks.

And, you're absolutely right, I need to go back to the basics. Test for fuel, spark, air. I've been so convinced that this was a sensor or a failing component, I've yet to do the basic checks. There are a *lot* of variables at play here, as it's a car with a rough history. Let me go back to the basics & make sure I didn't forget something silly...like forgetting to hook up the coil wire.

Not saying I've done that before...

...not saying I haven't... :toothy7: