Does anyone know which sensor is the Bank 1 sensor 1? (as in where it is on the vehicle because there is four and two of them are right next to each other) and how do I take it off? I got under and I could get one arm up to it, but couldn't manage to get my other up there to pull. I took off the tire, as well as the splash gaurd. No go.. is there some tool? or another way to get up there?

 

I can't recall how they are numbered now, but I know which one you are talking about by the way you are describing it, the one on the passenger side before the catalytic converter? I had to replace the one behind the catalytic converter on that side and the one before the catalytic converter on the other side. They were not too bad to get to. I saw the one you were talking about when I was looking around. I think your approach thru the wheel well with the tire and splashguard out is the right approach. There is a socket?/wrench? You can buy/rent for this that has a slit in the side to allow it to be put on the sensor around the wires. I knew I was going to replace them so I just cut the wires off right at the sensor and used a box end wrench, however that really burned a bridge. Don't use an open end it you can avoid it. Also I read something that helped a WHOLE LOT . Start the engine and get the exhaust fairly warm, not skin burning hot, just before you remove the sensor. Doesn’t take long. Amazing how much easier to remove the sensors with the pipes warm. As far a reaching that sensor thru the wheel, I don't know. If that special tool with the slit is a socket maybe you could put a long breaker bar on it.

Another problem I had was reconnecting the sensor connectors. I got replacement OEM type with the correct connectors. But holy moly....talk about something almost impossible to do. One connector I had to get to was between the firewall and the back of the engine, a space I could hardly get my hand in. I couldn’t even get the old one loose!!!! And I knew trying to line up the new connector back there would be a nightmare. So I clipped the wire off the old sensor as close to the sensor as possible and clipped the connector off the new sensor right at the connector end and ended up splicing them. Worked fine.

Try finding that split socket thingy….I bet it may be the ticket

Good luck

JD

 

If you use the special O2 sensor socket, it's difficult to get a rachet on the back of it due to close quarters. I used a brake fitting wrench which covers more of the hex 'diameter'. I was then able to get a couple of decent wacks on it with a 3 lb. sledge to break the sensor loose. Also, the electrical connector on the PCM side is clipped on with a barb connector. If you pry it loose with a long screwdriver, it will give you a little more room to mate and unmate. You can reinsert the barb when you're done. Through the wheel well with the inner fender removed is the only way to go. If the new sensor doesn't come with anti-sieze on the threads, be sure to add some.

 

O2 #1 is on the rh side front o2 sensor. An easy way to remember, is o2 #1 is on the cyl. #1 side. Also, dont cut and splice wires to o2 sensors, some use the wire to get air to the inner works of the sensor. believe it or not they do.

 

I haven't heard of that, but may be true on some cars. However, choices for aftermaket replacemet of the O2 sensors on my Explorer included a universal sensor with no connector that comes with a splice kit. The one I cut and spiced had normal looking wires; 4 each, insulation on the outside, just wire on the inside. Didn't see anything unsual about the wires and the sensor has been working find since I installed it over 6 months ago. I would agree , that if you can avoid spicing, it would probably always be better.

JD

 

Do you have the 5.0 V8? If so you will have to go through the top under the console to get to the connector. The sensor can be reached from underneath using a flare wrench.

 

All this of course works if no one has switched the wires around before you got there.

My 94 w/4.0 needed one (R or L I can't remember now) so I changed it, still needed the same one? Seems that the wires were on the wrong sides from the factory..... But it runs good with 2 new ones.

 

all right thanks everyone. I have yet to get under there due to a busy schedule. but I plan to by this weekend. thanks for all of the help

 

Be sure and tell us how you did. Maybe you will discover some tricks in changing these sensors you can share with us. I would be particularly interested in any easy ways you find to mate and unmate the connectors.

Good luck

JD

 

gman88, How do you go under the console to reach the connector on the V8? Unplugging the connector is the real problem.

 

You need to remove the console.

Here are some instructions I'm copying and pasteing (not my work), they should work for a 97 Mountaineer:

There are four bolts/screws holding the console in place. Two at the front that bolt into a bracket made for the console. Two in the middle that go into the floorboard.

Also, there is a bracket at the rear that holds console to the floor. Basically a bracket with slots is on the floor. Then two L shaped brackets coming from the console that slide into the slots.

Removal of the console:

The front plastic piece with the little cubbies, pull straight up. It has four clips holding it in place. Then the piece with the cup holders pulls up, two clips towards the back hold it in. Go easy, so as not to break off those clips.

Then remove the four gold colored bolts. Then unbolt the big wiring harness at the front.

Then slide the console towards the rear to pull the brackets out of the slots. Takes effort and you have to pull HARD. Hard to find a good place to hold onto. You've got to shaked it a bit to get it moving. Your grip needs to be low, just above carpet height.

 

After the console is removed you have to cut the carpet (I used an "I" pattern) under the console to access the heat shield plate. Remove the four screws from the plate and slip the plate out from under the carpet. Once the plate is out the connectors are right there on top of the transmission. I would have been lost if not for the words of encouragement from viiidude.

 

Sounds like you know your stuff. My father and I will check into it as soon as we can. And for JD I got up under and did everything you suggested, but still could not get the connecter off. Thanks for the help everyone. I hope this time we can get it, that "Check Engine" light is starting to burn a whole in my eye.

 

Have you tried this? The electrical connector on the PCM side is clipped on with a barb connector. If you pry it loose with a long screwdriver, it will give you a little more room to mate and unmate. You can reinsert the barb when you're done. Through the wheel well with the inner fender removed is the only way to go. If the new sensor doesn't come with anti-sieze on the threads, be sure to add some.

 

If you are working on a 5.0, through the wheel well will led you nowhere. So, removing the inner fender is only a waste of time.