I have seen lots of talk about swapping out stock OEM O2 sensors with new ones. In particular sensors builts by Wells are touted as the best. What is the advantage or gain? I can't find anything that supports changing them out except in the case of a failure.

 

???

Nope. stick with OEM ( made by Bosch).

Forget Ford's TCO agenda - these are a maintenance item.

Front two - Change 'em every 30-50K for best emissions, idle quality & performance.

They start to degrade as soon as they're used.

Rear two - if/only when they fail.

 

I changed mine at about 70K thinking it would help with mpg. It didn't help at all. Leave the front OEM in untill they go bad. The back two don't effect the tuning of the engine.

 

Good advise. My front stockers lasted for 150,000 ish. Then I got the knucklehead idea to change them. I wasted my money. But I saved the old ones, and I rescued a friend with one of them.

 

This is how it was explained to me by a very knowledgeable tech.
The O2's on most all newer OBDII are a heated O2. Its the heated part of it that gets weak. These new O2's need to run at a high temperature, higher than simply being bolted onto the exhaust pipe. When they get old since the heating element within is not so good any more, they make the engine run not as efficent. Most people who claim much better fuel economy after a new set is installed, live in colder northern climates. Where as most people who claim no real improvement live in warmer souther climates. Is this starting to make sense???
There were some people looking to save some $$$ who tried insulating the O2 with some folded up aluminum foil and tieing it with wire, They document a significat signal difference once insulated, yeilding better economy.
I myself live in NY and bought two Expeditions with 5.4's, I just purchased EIGHT O2's to do all on both vehicles, OOOUUCCCHHH!!!! $$$. Yes, I know that the rear ones only monitor the cats, and only need to be changed if they are bad= engine light. But ,I've had to change several bad ones on several Fords,so if I'm under the truck already why not.
My wifes truck I will not mess with, for fear of death. My truck however, I plan on doing myown insulator to test. I think that a cut peice or two of copper conduit will be better than aluminum foil.

I hope this was educational, ....Oh did I spell that word wrong??

 

Michigan would definitely count as a colder northern climate. Let me know if those work out for you, because I might do mine if they do.

Thanks!

 

lowflyingbird, I think I would find another tech.
The heaters only job is to heat the O2 sensor up faster. The temp. of the exhaust is more than enough to keep it hot. There was a time when O2 sensors had no heaters and worked just fine.
The only reason they have the heaters is to reduce the amount of time the engine spends in open loop. Open loop is when the PCM uses set parameters to control the fuel curve. When the O2 gets hot enough it starts sending a signal to the PCM, the PCM then makes adjustments to the fuel curve.
This is closed loop.

 

Quite right. The O2 sensors fail when they slow down in their reaction time to the levels of O2 between outside or ambient air and the exhaust stream. This is almost always because the tip of the sensor has become contaminated. As stated, the heaters allow quicker transition to closed loop and is a failsafe method of ensuring the O2 sensor doesn't cool down again, which probably isn't likely anyway.

 

At 309,000 miles my truck has 2 of 4 original o2's. Anyhow this has been a topic here before. https://www.f150online.com/forums/sh...d.php?t=123409