I'm working on putting a 5.9L and a 46re in a Wrangler. I had the harness all done and installed, had the jeep running, but had to pull the harness again to chase down a park/neutral switch code. I think i have that figured out, my question is regarding the O2 sensors wiring.

The other issue I'm having is a few moments after first start the jeep will begin to run rough, the intake will begin to such a lot of air, the RPMs will drop a little. this clears up after I rev it a little and then it runs fine. My guess is this is because the engine is not going into closed loop (I'm just guessing here) So I thought a possibility might be incorrect wiring on the O2 sensors. ( I made the harness myself and I'm no expert, just a glutton for punishment, I guess)
Here's a shot of the O2 sensor wiring as it is connected to the PCM, I'm wondering why the up and downstream sensors are both going to the same pin, pin 24. My computer pin 26 is empty.
Currently, I have just the upstream sensor going to pin 24 and just the downstream to pin 25, is this correct.

Thanks.

 

I can't directly answer your question, but comparing later wiring diagrams some pins are used only with California emissions and others have different designations in CA vehicles vs others. HTH

 

Hey, I remember you, you helped me figure out the TPS issue I had with this.

Do you think the front and rear O2 sensor could be connected to the same pin from the factory?

Thanks again.

 

Not at the same time. I'm not that familiar with the older trucks (mine is a 2001) but I know there were years were Federal trucks had only one O2 sensor and CA trucks had two. That's why the pins at the ECM have different uses.

 

Did you happen to install wideband O2,It should be the round tip nose.Might be the problem.Just a thought>>>>>>>>>>>>>>>>>>>

 

I put in Bosch, OEM replacement ones, The connectors match with the stock harness. They are the rounded nose. Bosch 13280 front, and 13122 rear.

Do my symptoms sound like a closed loop issue.
It wasn't a big enough a problem before so I would be motivated to pull the harness for it, but since it's out already, I'll see if I can chase it down. I did not have any related codes.
Just the P1899 for the park switch.

 

Our trucks don't like Bosch sensors

 

Yeah, the fanatic is correct, our trucks really don't like the Bosch sensors. NTK, or Denso please.

Verify the wiring, make sure everything is correct. The engine won't go into closed loop until coolant temp reaches around 108 degrees....... if the engine is already warm, it will still take a couple minutes for the O2 sensors to warm up. (that's what the heater circuit is for.) If, when warm, it idles fine for a couple minutes, and then starts running rough....... that's usually an O2 sensor problem. (and with the bosch sensors, your wiring may be fine, just the sensors aren't quite right. )

 

That's what I was thinking also. It's entirely possible I have the wiring wrong. I'll check that first and then see about different O2 sensors.

Thanks.

 

I found at least one mistake in the park switch wiring. I had pin 1 going to a 12v hot source, instead of computer pin 2. I've checked pin 2 on the park switch and it's correct. Now I'm not sure on pin 3. backup lamp feed, can someone tell me where this goes on a Ram. I have a FSM, but I can not figure out where this wire goes. The location will likely not be the same for me, but at least this will give me a starting point. My harness is a combination of jeep and ram.

I also have mistakes on the O2 wiring. I'm now realizing that i did not really understand where these wires went to initially and did what made sense to me at the time, I was wrong. I'll need to go through the O2 wiring also and will have questions about that.
I can post screenshots of the schematics if you need.
I really appreciate the help here.
Thanks again