O2 sensor

[shadow88]

In the middle of my 4.0 swap, should I swap the o2 sensors? Any info would be great!

 

[rochhound]

you should use the exhaust crossover that came with that year 4.0,early 4.0's had one
sensor and later had two.

 

[shadow88]

It's from a 91 and only has 1, I thought I read some where that I could use my 2.9 exhaust? I was just wondering if the 4.0 o2 senser was different , it has the same plug in

 

[rochhound]

91 4.0 may bolt up to 2.9 crossover but its a little smaller in id" thus could cause to much back pressure on engine. i had to use a 4.0 94 exp has two sensors good luck

 

[shadow88]

Any other options on this?

 

[armadillon]

From all of the 4.0 swaps I've seen everyone pretty much used all of the sensors that came with the motor they were swapping in.

Here's a thread reference for you:
http://www.therangerstation.com/forums/archive/index.php/t-15480.html

 

[disciplerocks]

I used the Explorer donor's Y-pipe and O2s

 

[adsm08]

91 4.0 may bolt up to 2.9 crossover but its a little smaller in id" thus could cause to much back pressure on engine. i had to use a 4.0 94 exp has two sensors good luck

I just stripped the engine wiring out of a 94 Explorer this morning and only found 1 oxygen sensor.

 

[disciplerocks]

^Mine was from a 94 Explorer and had 2

 

[adsm08]

Hmm. There must have been a mid-year change.

 

[armadillon]

Does that mean we've established that none of us are sure how many sensors came with what model and that we should pull the o2 sensors and Y-pipes along with the motor we're swapping in so we don't have to leave it to conjecture?

I've been kinda curious myself since the 4.0 or V8 is in my near future

 

[shadow88]

My donor is a 91 Navajo and it only has one o2 sensor

 

[adsm08]

Does that mean we've established that none of us are sure how many sensors came with what model and that we should pull the o2 sensors and Y-pipes along with the motor we're swapping in so we don't have to leave it to conjecture?

I've been kinda curious myself since the 4.0 or V8 is in my near future

No, it means that Ford does stupid mid-year running changes and you need to be careful. Either that, or there was a second one that I unplugged from the top without ever actually seeing what the plug went to.

My donor is a 91 Navajo and it only has one o2 sensor

I'd go with the newer sensor, that should go into the existing hole.

 

[armadillon]

that should go into the existing hole.

*snicker*

 

[disciplerocks]

Use whatever came on your donor so it matches the harness and ecu.