Finally got around to jacking up the 92 E150 351W and working on the exhaust, what i discovered was more disturbing than the current issue, when Ford was laying out the plans the exhaust they decided to place a small diameter balance pipe between the head pipes and placed the O2 sensor directly in the middle of that balance pipe, I was shocked to say the least.
From what i have seen on every other vehicle and from what I have learned this was totally incorrect placement of the O2, I can understand their logic by wanting to combine all the cylinders into the equation but they made the mistake of removing the O2 sensor away from the flow of hot gases, no matter how much you tune that engine it is still for lack of a better word (wrong).
Now I have to relocate the O2 and place the bung in one or the other head pipes, whichever one is easiest to get at i suppose.
I am excited because i already know this is going to make a major impact on the tune and just might run like the engineers originally intended it too, the reason i posted this in the engine section is because it just might apply to other vehicles that suffer from the same issue with the state of tune, I will go so far as to say that even if the engine is running good there will be substantial change by relocating the O2 to the proper location which is for all intents and purposes directly in the flow of the hot gases.
Doesn't matter if the O2 is heated or not, still won't work correctly the way they designed and installed it..

 

What makes you think it's wrong? Think maybe Ford took into account the readings the O2 sensor would send out and programed the computer with that in mind? Besides, how many trucks, vans, cars did Ford build that way? Millions? They seem to be working just fine. What are you trying to acomplish?

 

Yeah I'm not so sure you're gonna see any difference. I know the O2 sensor doesn't need to "see" both sides of the engine.. my truck has been running that way for a decade or more since I removed the stock exhaust and installed longtubes, but overall as long as the O2 is seeing some exhaust gas it'll do it's job and proof will be in the color of the plugs and gas milage.

 

They did it so the o2 would see the pulses side to side..

I have mine in my passenger side long tube header.. No issues here

 

Unbelievable, so far I am the only person that see's a problem with it. We've come to the conclusion that the O2 does not have to be mounted in the flow of the hot gases to properly read the amount of Oxygen, it can be mounted off to one side buried inside another pipe... on that note it's time for a smoke break and I don't smoke tobacco..

 

It's a perfectly fine way of doing it obviously as they did it for 10+ years with no issues

 

Exhaust is a closed system so the only thing the O2 is going to see is exhaust gases, and since most of these trucks use a batch fired injection system(multiple injectors fired at the same time) the computer can't meter fuel on an individual cylinder basis so there is no benefit to the O2 seeing individual exhaust pulses.

 

You're right about bank fired injection not needing individual O2 sensors for each cylinder. I will add that the response of O2 sensors are too slow to react to individual pulses, so the EEC has to look at averages over time, even if they do install individual sensors on each cylinder.

One major requirement for the sensors is that they need to be run at very high temperatures (don't remember the range), so they should not be installed too far away from the heads. I also remember reading about the optimal place to install a balance pipe between the two sides is where exhaust tends to build up the most heat and pressure. So putting the O2 sensor in the crossover pipe may be the best way to do it when you want to install just a single sensor on a dual-exhaust system.