Major Mileage Drop

[Ranxeroxlubna]

I am getting codes for O2 sensors, one upstream one down stream, so I thought I'd go ahead and replace both of the upstream sensors. What is the correct part numbers? I tried to do some research but got lots of conflicting info. Some say "use Motorcraft, Bosch are junk" Others say Bosch is the same thing. Do you have a good part number I can look for? '97 Mountaineer 5.0.

According to the Ford Parts website your truck uses the same as mine, only 3 (2 upstream - 1 downstream) versus my 4.

Part #9F472 (DY-831) for the upstream O2 sensors, and Part #9G444 (DY-1081) for your downstream sensor.

I have a "Bosch" O2 sensor I purchased from Napa in B2/S1 position and the Ford sensor I bought from the dealer in B1/S1 position. Both are operating nicely and I'll let you know if there is a failure or any problem with either.

I have heard that "Bosch is Junk" rubbish a lot. I've used Bosch products a lot. The are the OEM producer of a great many sensors and electronics for the automotive world in Europe and here in the states. I have NEVER had a problem with their products because I have installed the CORRECT product required. Bosch is the manufacturer of Fords O2 sensors, but Turdle may be correct in that the Ford folks get tested ones.

I've run Bosch plugs and sensors in my Ford Explorer 4.0 and my Chevy 5.7 and my Chrysler 4.2 turbo, and while I switched out the plugs on my Merc, it hasn't made a difference in it's running that I've noticed. Most of my Bosch plugs are the 4-point iridium series. The plugs in the Ford (Bosch 2 point platinums) have been running for 80,000+ miles and are still in great shape. The Chevy has had them in for better than 60k miles and it runs great. The Chrysler turbo runs clean, but they've only been in there for about 22k miles.

I'm tracking my performance with the Motorcraft plugs and will swap them out with the Bosch to see what, if any difference there is.

But that is another thread.

 

[Turdle]

I am getting codes for O2 sensors, one upstream one down stream, so I thought I'd go ahead and replace both of the upstream sensors. What is the correct part numbers? I tried to do some research but got lots of conflicting info. Some say "use Motorcraft, Bosch are junk" Others say Bosch is the same thing. Do you have a good part number I can look for? '97 Mountaineer 5.0.

dealership will have good part numbers. You do need to know which bank though, as I believe there are 2 different part numbers involved. The downstream sensors are different than upstream, bank 2 s1 has a shorter lead than bank 1 s1 if I recall correctly.

The last 02 sensors I bought from other than a dealer were for my 93 off ebay from a guy who had bought ford sensors and decided not to use them. For my and my son's mounty's though I went to the dealership. If you can get them to give you a part number, search for that number on ebay and amazon

Because of the conflicting info you mention, my "logic" is not to try to save a few dollars if a genuine Ford part might save fuel in the long run. The price difference is around 35.00 from what I remember. I feel a good 02 sensor will definitely save a tank of fuel in it's lifetime. I have no data to support this though.

 

[Ranxeroxlubna]

dealership will have good part numbers. You do need to know which bank though, as I believe there are 2 different part numbers involved. The downstream sensors are different than upstream, bank 2 s1 has a shorter lead than bank 1 s1 if I recall correctly.

The last 02 sensors I bought from other than a dealer were for my 93 off ebay from a guy who had bought ford sensors and decided not to use them. For my and my son's mounty's though I went to the dealership. If you can get them to give you a part number, search for that number on ebay and amazon

Because of the conflicting info you mention, my "logic" is not to try to save a few dollars if a genuine Ford part might save fuel in the long run. The price difference is around 35.00 from what I remember. I feel a good 02 sensor will definitely save a tank of fuel in it's lifetime. I have no data to support this though.

Hi, I just wanted to post where I garnered my sensor information from. There is a schematic you can open up on this page. http://www.fordparts.com/Commerce/P...earch=true&year=1997&make=Ford&model=Explorer

They only list 1 part number for both upstream sensors...the counter person informed me that in the interest of economics, they make the sensors with the same length of wiring.

My 2 cents.

 

[oharris]

According to the Ford Parts website your truck uses the same as mine, only 3 (2 upstream - 1 downstream) versus my 4.

That diagram is wrong, mine has 4 just like yours.

Part #9F472 (DY-831) for the upstream O2 sensors, and Part #9G444 (DY-1081) for your downstream sensor.

They list both DY-831 and DY-832. Though for some reason they both have the 9F472 number.

 

[oharris]

dealership will have good part numbers. You do need to know which bank though, as I believe there are 2 different part numbers involved. The downstream sensors are different than upstream, bank 2 s1 has a shorter lead than bank 1 s1 if I recall correctly.

The last 02 sensors I bought from other than a dealer were for my 93 off ebay from a guy who had bought ford sensors and decided not to use them. For my and my son's mounty's though I went to the dealership. If you can get them to give you a part number, search for that number on ebay and amazon

Because of the conflicting info you mention, my "logic" is not to try to save a few dollars if a genuine Ford part might save fuel in the long run. The price difference is around 35.00 from what I remember. I feel a good 02 sensor will definitely save a tank of fuel in it's lifetime. I have no data to support this though.

So is there a difference between a motorcraft sensor bought from amazon and a motorcraft sensor bought from the dealer? I get what you are saying about quality parts being worth it, but padding the dealers bottom line is not my idea of fun unless there's really a difference.

 

[Ranxeroxlubna]

That diagram is wrong, mine has 4 just like yours.



They list both DY-831 and DY-832. Though for some reason they both have the 9F472 number.

Hmmm, the differing numbers would be the differentiation in wire length; I would guess that Turdle is correct about length of wire and the dealer guy was wrong...I am concerned that this is 2 times the dealer employees were wrong about their own products. When I called the dealer, the parts person only asked me for the Part (9F472) number.

It fit, so I didn't give it much thought.

 

[oharris]

Hmmm, the differing numbers would be the differentiation in wire length; I would guess that Turdle is correct about length of wire and the dealer guy was wrong...I am concerned that this is 2 times the dealer employees were wrong about their own products. When I called the dealer, the parts person only asked me for the Part (9F472) number.

It fit, so I didn't give it much thought.

It's probably like you said, they went to one wire length under the new number rather than two under the old numbers. That doesn't explain two different prices though.

 

[Ranxeroxlubna]

It's probably like you said, they went to one wire length under the new number rather than two under the old numbers. That doesn't explain two different prices though.

This is interesting.

For my 1998 5.0, the Ford parts site lists only 2 numbers for sensors. Upstream and downstream. I can't find the other number you saw.

 

[oharris]

This is what I see.

 

[Ranxeroxlubna]

I can't post the picture on here as I'm not a Superduper member, but if you go to the same Ford parts site, and put in for a 1998 Mercury Mountaineer, 5.0, you will see only 2 options for the O2 sensors, upper and lower.

Seems like the counter guy was right, as is Turdle and the rest.

 

[Ranxeroxlubna]

Well, the good news is that the mileage is up. The bad news is that it's only up to 12.76 MPG.

I'm open to any suggestions.

 

[Ranxeroxlubna]

Update

After running 2 tank-fulls of gas and Seafoam, my MPG is 16.87; this on winter gas.

Thank you Turdle for your input and for all of you who pitched in.

 

[oharris]

They list both DY-831 and DY-832. Though for some reason they both have the 9F472 number.

I finally got this and a few other things done. The difference between the two numbers was indeed the length of the leads. I am hoping to see some increase in mileage

 

[oharris]

Well, after replacing the two primary O2 sensors, I am not getting any better mileage. Not any worse, but not any better. I was getting codes for Bank 1 sensor 1 and bank 1 sensor 2. I replaced both primary sensors and took the primary sensor from Drivers side (Bank 2 sensor 1) and put it in the secondary position on the passengers side (bank 1 sensor 2). It was a generic replacement sensor and since the secondary sensors are only there for emissions purposes, it seemed like a good idea. The problem is I an still getting an O2 sensor code for Bank 1 sensor 2. Any ideas why I would still be getting this? I'm going to double check that it's fully plugged in but otherwise I don't see why it wouldn't work as a secondary sensor when it worked fine as a primary sensor.