360 magnum O2 sensor install help

[Truckie]

Here’s the scenario: 1999 360 magnum swapped into a 67 dart. Running stock efi, computer, and harness from computer to the fuse box. Summit headers with dual exhausts. Right now I don’t have any O2 sensors installed. I believe the donor truck only had on pre-cat O2 that was located just before the cat where pipes joined. I don’t recall an unused plug in the engine harness for the O2 sensor to plug into. I’m thinking the wiring must have come from the large fuse box. Most of that part of the harness is gone. I’m only getting codes for bank 1 sensors so pretty confident the donor didn’t have 4 sensors.

Now for my questions:
1. How can I hard wire the pre cat sensor so it will work assuming that part of the harness doesn’t exist anymore?

2. If I just run one sensor, do I put it in an H pipe so it reads both sides?

3. if the donor truck only had one pre cat O2, how can I add a second sensor for the other side of the engine? Will the computer recognize 2 if the donor only had one?

thanks

 

[jbc426]

Here’s the scenario: 1999 360 magnum swapped into a 67 dart. Running stock efi, computer, and harness from computer to the fuse box. Summit headers with dual exhausts. Right now I don’t have any O2 sensors installed. I believe the donor truck only had on pre-cat O2 that was located just before the cat where pipes joined. I don’t recall an unused plug in the engine harness for the O2 sensor to plug into. I’m thinking the wiring must have come from the large fuse box. Most of that part of the harness is gone. I’m only getting codes for bank 1 sensors so pretty confident the donor didn’t have 4 sensors.

Now for my questions:
1. How can I hard wire the pre cat sensor so it will work assuming that part of the harness doesn’t exist anymore?

2. If I just run one sensor, do I put it in an H pipe so it reads both sides?

3. if the donor truck only had one pre cat O2, how can I add a second sensor for the other side of the engine? Will the computer recognize 2 if the donor only had one?

thanks

1.) There are 3 wires that go to the O2 sensor, 12V switched power, ground and the 5V signal wire that you will need a pinout diagram for you harness to locate.

2.) No. Run the one O2 sensor to only one side of the motor. The 5V input signal it sends will be used for all cylinders. It needs to be closer to the cylinders than it would mounted be beyond the H pipe.

3.) You could call Solo PCM's in Florida and talk to them. If anyone can do the programming changes to add a second sensor, they could, but it is not necessary. You can run what you have once you add the O2 sensor.

 

[Truckie]

1.) There are 3 wires that go to the O2 sensor, 12V switched power, ground and the 5V signal wire that you will need a pinout diagram for you harness to locate.

2.) No. Run the one O2 sensor to only one side of the motor. The 5V input signal it sends will be used for all cylinders. It needs to be closer to the cylinders than it would mounted be beyond the H pipe.

3.) You could call Solo PCM's in Florida and talk to them. If anyone can do the programming changes to add a second sensor, they could, but it is not necessary. You can run what you have once you add the O2 sensor.

Thanks for the info. I haven’t bought an O2 sensor for it yet, but I’m thinking they are a 4 wire sensor. If I remember correctly 2 white, 1 black, 1 gray. Also I have come across this info (see pics) I’m thinking a 99 Dakota would have same pin out, maybe not.
So if I’m understanding correctly, I hook one wire to ground, one to 12v with key, and the other will splice into the engine harness on the correct wire for the sensor. Sound correct?

 

[Bobzilla]

The the oxygen sensor itself:
Pin 1 is ignition power from the fuse inside the PDC.
Pin 2 should go to a good clean chassis or engine ground. It was G105 in your donor truck.
Pin 3 should splice into the other sensor grounds supplied by PCM, by splicing into S118 of your donor truck.
Pin 4 should go to PCM connector 1, and it looks like it should be pin 24 on a 1999 5.9L donor truck without heavy duty emissions.

Also, if you want left and right bank oxygen sensors instead of one upstream and one downstream, it looks like you would need to have your PCM programmed with heavy duty emissions, and then change the oxygen sensors and wiring to match that layout.

 

[MOPAROFFICIAL]

My 96 has two o2 sensors. Pre and post cat. Single exhaust fwiw.

 

[Bobzilla]

My 96 has two o2 sensors. Pre and post cat. Single exhaust fwiw.

That is the regular light duty emissions setup that most OBD2 trucks will have. Mine are that way too.

If it was heavy duty emissions, and I think maybe California emissions too, it will have a pre-cat O2 sensor for the right bank cylinders, and a pre-cat O2 sensor for the left bank cylinders. This setup is preferred for dual exhaust engine swaps, but not required.

 

[MOPAROFFICIAL]

That is the regular light duty emissions setup that most OBD2 trucks will have. Mine are that way too.

If it was heavy duty emissions, and I think maybe California emissions too, it will have a pre-cat O2 sensor for the right bank cylinders, and a pre-cat O2 sensor for the left bank cylinders. This setup is preferred for dual exhaust engine swaps, but not required.

I agree and why I thought to mention mine is single exh. Wish it was dual... but then again that's an extra o2 sensor to replace layer down the road.lol

 

[Truckie]

The the oxygen sensor itself:
Pin 1 is ignition power from the fuse inside the PDC.
Pin 2 should go to a good clean chassis or engine ground. It was G105 in your donor truck.
Pin 3 should splice into the other sensor grounds supplied by PCM, by splicing into S118 of your donor truck.
Pin 4 should go to PCM connector 1, and it looks like it should be pin 24 on a 1999 5.9L donor truck without heavy duty emissions.

Also, if you want left and right bank oxygen sensors instead of one upstream and one downstream, it looks like you would need to have your PCM programmed with heavy duty emissions, and then change the oxygen sensors and wiring to match that layout.

Thanks for the information. Can you send me a picture of or a link to the diagram you got the wiring info from? If it was in your head, I guess a pic of your brain will do. Everything you said made sense, I’m just not sure what wire S118 is.
Also sense you seem to know wiring and you do a great job explaining what to do, can you help me out with the battery temp sensor wiring?

thanks.

 

[Bobzilla]

I am using a factory service manual I bought back around 2002 when I first got my 1999 Dodge Ram 2500 with 5.9L gas engine. I won't be copying any pages because it is copyright protected material and I won't risk that trouble. I would suggest searching online or buying a digital cd copy from someone like RockAuto.com under literature for the selected vehicle.
Battery temperature sensor pin 1 uses the same clean sensor ground from PCM connector 1 pin 4, through same splice S118. The battery temperature sensor pin 2 goes to PCM connector 3 pin 15.

What happened to all of these wires and connectors? Were they cut out of the harness already, or are they still there somewhere? If everything was cut from the harness, the wires should still be there at the spot they were cut from, and that is where you should splice them back in. If you are not sure where the wires were removed, start at the crankshaft position sensor or camshaft position sensor and start opening the harness covering, tracing back the wire that is black with a light blue tracer (BK/LB) until you find the splice S118.

 

[Truckie]

I am using a factory service manual I bought back around 2002 when I first got my 1999 Dodge Ram 2500 with 5.9L gas engine. I won't be copying any pages because it is copyright protected material and I won't risk that trouble. I would suggest searching online or buying a digital cd copy from someone like RockAuto.com under literature for the selected vehicle.
Battery temperature sensor pin 1 uses the same clean sensor ground from PCM connector 1 pin 4, through same splice S118. The battery temperature sensor pin 2 goes to PCM connector 3 pin 15.

What happened to all of these wires and connectors? Were they cut out of the harness already, or are they still there somewhere? If everything was cut from the harness, the wires should still be there at the spot they were cut from, and that is where you should splice them back in. If you are not sure where the wires were removed, start at the crankshaft position sensor or camshaft position sensor and start opening the harness covering, tracing back the wire that is black with a light blue tracer (BK/LB) until you find the splice S118.

I need to check the harness again but I don’t remember any unused plugs. I cut all the wiring off from the power distribution block to the firewall. I was wondering if maybe the O2 sensor wiring was in that part of the harness and not in the part from the computer to the PDB

 

[Bobzilla]

Pins 2, 3, and 4 do not go through inline connectors or the PDC. They should be in the harness somewhere. Pins 2 and 3 do go through splices, and pin 2 actually goes to the ground G105 on the left front of the engine, and actual ring terminal mounted to the engine itself.
Pin 1 of the O2 sensor does go through a splice, and then an inline connector C130, and then to the PDC to get power from the fuse for the O2 sensor heater.

 

[Bobzilla]

The branch of the harness for trans connectors and O2 sensors should be starting about 55 inches away from PCM connectors, in their own branch. O2 sensor connectors on this harness are pointed out with white chalk.

 

[Truckie]

The branch of the harness for trans connectors and O2 sensors should be starting about 55 inches away from PCM connectors, in their own branch. O2 sensor connectors on this harness are pointed out with white chalk.View attachment 1715741399

I found the wires. They were cut off about 6” after they split from the main harness. I don’t remember cutting them off, but I guess I did. Hopefully everything is there for me to connect to.

I do have another question. About a foot or so from the computer there are two wires taped together that come out of the harness. There is no plug on them, but in your picture I think it is the wires connected to the green plug. If I remember correctly one wire was blue and the other brown. What do they go to?

thanks.

 

[Bobzilla]

I found the wires. They were cut off about 6” after they split from the main harness. I don’t remember cutting them off, but I guess I did. Hopefully everything is there for me to connect to.

I do have another question. About a foot or so from the computer there are two wires taped together that come out of the harness. There is no plug on them, but in your picture I think it is the wires connected to the green plug. If I remember correctly one wire was blue and the other brown. What do they go to?

thanks.

The green connector is for the air conditioning (AC) low pressure cycling switch. It would be on the accumulator right by the PCM on your donor truck. Those wire colors match too. If you are not going to use AC just leave them taped back into the harness in case you want to add AC later.

 

[Truckie]

The green connector is for the air conditioning (AC) low pressure cycling switch. It would be on the accumulator right by the PCM on your donor truck. Those wire colors match too. If you are not going to use AC just leave them taped back into the harness in case you want to add AC later.

Thank you. You have been extremely helpful. I appreciate the amount of detail you put into your replies. You, along with TT5.9Mag are definitely assets to the forum.

 

[Truckie]

The O2 sensor I got has 2 black wires, a white, and a blue. If the diagram I found online is correct, the black wires are pins 1 & 2, the white is 3, and the blue is 4. Does that sound right? I would think the two black wires would be the grounds, but earlier it was stated that 2 & 3 were the grounds.

 

[Truckie]

Ok, checking to see how close I am. There are 2 green with white tracer wires that are spliced together. They are hot with the car running and the color matches the wire coming out of the 15 amp O 2 sensor spot in the PDC. This hooks to pin 1 from sensor?

there are a couple black with white tracer wires that appear to be grounds to the chassis. One of them can connect to pin 2?

Pin 3 should connect to a black with blue tracer wire because those are the grounds from the PDC?

pin 4 should connect to the tan with white tracer wire?

let me know if this looks right. Some diagrams I look at show that 1 & 3 are grounds.
I am including a picture of the back of the O2 sensor plug. It shows that wires 1 & 2 are black, 3 is white, and 4 is blue.

 

[Bobzilla]

I am not sure if the wire colors on the sensor itself are the same between different manufacturers, so you must wire the harness side connector according to the diagrams or another comparison vehicle.

I will double check my harness in a while and get more pictures. Raining outside here right now.

 

[Bobzilla]

I forgot to update this. Here is pictures of the wires going into the connector on the harness, for what should be the pre-cat O2 sensor, the front one.

 

[Bobzilla]

Here is O2 sensor connector on another project harness. This one I cut the O2 sensor side so I had both sides of the connector.