I have an 01 that I replaced the engine with a 98 ZJ.
With the swap I did a speed daddy header.
IIRC, I should have 5 total O2 sensors.
At this time, I have two in the header.
My questions are;
Which of them adjust the fuel ratio?
How do I tell which is which?
Where should all the harnesses come from?
Mine only had two when I got the Jeep and want to make sure Im not loosing out on power or a whole lot of fuel.
TIA

 

IIRC, pre-cat O2's control fuel ratios, post-cat monitor emissions.

 

If your 01 is a CA emissions jeep, you should have 4 total. 2 in the manifolds pre-cats and 2 after the cats. The downstream cat under the jeep is not monitored and only adds back pressure to insure the upstream cats function properly. Federal emissions jeeps have 2, One in the header after the y-joint, and one after the converter under the jeep.

As already stated, the 2 pre-cat sensors determine the mixture control and the 2 after the cats monitor converter efficiency. It sounds like you only need 1 in the header, but you need 1 after the cat. The wiring for that comes thru the floor under the seat.

Actually in FL you probably only need the 1 in the header for mixture control.

 

Thanks, I need to clarify, all 01's are CAFE so I most definitely should have 5. Problem is, I have 3.
Im trying to figure out the harness situation since it is missing and how can I even tell if I have the right ones in the header.
Also, there are mixed statements on what the post-pre-cat O2's do. Hence why Im trying to get final answer on.

 

Nope, 2001 CAFE standard has 4. Just like Dave said.

I've not done it, but you might be able to wire the single upstream O2 sensor into both upstream inputs (i.e. splitting the signal)

 

Not enough inputs on the JTEC+ for 5 o2 signals. Four sensors. For factory equipment you will find the upstream connectors gray in color and the indexing tabs 90* apart from each other. The downstream connetors should be black with the indexing tabs at an acute angle.

 

I believe Speed Daddy only makes a header for a 91-99 Cherokee. The 2000/2001 stock setup is pictured below. You're going to need some creativity to make this work.

 

Last I knew FL wasn't emissions testing so that's why I said he only needs 1. It was a joke, son!

 

Well, then there have been some other changes as I have another O2 in the rear cat.
Thats why Im saying 5 total; I am counting the one under the Jeep as well as the two currently attached and the other two Im missing.

 

What is the part number on the ECU.

 

Youre right, no exhaust Gestapo here yet thank God.
What was a joke?

 

Not sure if right number, but it says CHRYSLER P/N P56041 795AD
Looks like sticker was placed over another one.

If correct, then it matches this chart http://board.moparts.org/ubbthreads/...FlashAvail.pdf

 

I'm curious, what's your plan here as I don't think that's going to bolt up to your existing exhaust? Change to the old exhaust setup, single cat and downstream O2 sensor? Deleting the cats altogether and run a fake O2 simulation for the downstream?

 

Ive been running like this for over two years. I have the older 7120 head as came with the ZJ engine.
Basically the exhaust shop took care of this, but down pipe was reused IIRC.

As for downstream O2's, again, I am missing them and the wire harness for them.
This is exactly what I am asking about in the OP as the PO must have removed them.
So I really cant answer that question, yet

 

Ah, did perhaps the previous owner install O2 sensor simulators like this one? http://www.bigdaddiesgarage.com/straight-cel-fix.html