No start, no 5v power to cam sensor, about to give up….

[Anak]

Here is an effort at some pics. I don't know how well they will translate to your situation, but this is at least what things looked like originally.

First pic is of the downstream O2 where it plugs into the cat (not an original cat, but a CARB OBDII approved cat, so it should be pretty close to what was factory):



Second pic has the O2 sensor plug in the upper RH corner and shows that wiring coming from the same harness as the VSS:



Third pic shows that harness going up the firewall. The bulge at the bottom left is the starter, and up above you can see the bottom of the carbon canister. The harness in question is the larger one of the two.



Lastly, just for some sort of reference, is the upstream O2. This is in a Borla header (again CARB OBDII approved) which differs a bit from factory, but the wiring harness is not modified in order to reach that position.



Hopefully something in there will give you a point of reference which will help.

 

[Dborns]

Perfect. I wish I could post pics, but my upstream is in the same place. What I need to find is where the downstream wiring originates from so I can trace it from the harness all the way out to the sensor. The sensor for the downstream connector I can’t find….

 

[Anak]

Can you trace your VSS wiring?

Or does the CJ not use that? I would think the confuser would want an input though.

 

[Dborns]

Yes my VSS is another odd setup due to it going into the Dana 300. I noticed that area right where the VSS is connected, along with the sensor is completely covered in muck, grease, and T-case oil, (good old leaking CJ). I had a couple wires running down the frame around it but the only plug is not for an O2 sensor.

 

[Dborns]

I do have some small diameter coils running down that side of the frame but didn’t see and plugs. I need to open those coils up and look for the proper wires that would match an o2 sensor

 

[Anak]

In what part of the country are you located?

 

[Dborns]

In what part of the country are you located?

Just east of Kansas City MO.

 

[Dborns]

Here is an effort at some pics. I don't know how well they will translate to your situation, but this is at least what things looked like originally.

First pic is of the downstream O2 where it plugs into the cat (not an original cat, but a CARB OBDII approved cat, so it should be pretty close to what was factory):

View attachment 12365

Second pic has the O2 sensor plug in the upper RH corner and shows that wiring coming from the same harness as the VSS:

View attachment 12366

Third pic shows that harness going up the firewall. The bulge at the bottom left is the starter, and up above you can see the bottom of the carbon canister. The harness in question is the larger one of the two.

View attachment 12367

Lastly, just for some sort of reference, is the upstream O2. This is in a Borla header (again CARB OBDII approved) which differs a bit from factory, but the wiring harness is not modified in order to reach that position.

View attachment 12368

Hopefully something in there will give you a point of reference which will help.

I have the one small diameter tubing from the top of the fuel rail area, down to the upstream sensor. I don't see anything else obvious in the wiring harness that comes off that drivers side and down near the T-case. Again, I do have a couple small and large diameter looms going down the drivers side of the frame so tomorrow Ill open those to see what color the wires are in there. If I find the right colors, ill find the end and either a plug, or cut wires if I removed the plug for some reason. It would be awesome if I found damaged eirescthat had shorted out, but that probsbiy wont be the case.
I need to also figure out why my code reader wont communicate with the computer either. If it did that may narrow it down also.

 

[Dborns]

Can you trace your VSS wiring?

Or does the CJ not use that? I would think the confuser would want an input though.

Out of curiosity why do you ask? Could the VSS be an issue too? Would an issue with it cause a no-start? I'll have a better idea of its condition when I can degrease it because it is caked and nasty with fluids.

 

[Anak]

It would appear the VSS wires run parallel with the downstream O2 sensor wiring. If you can't find the wiring for that O2 sensor I would think following the VSS wires would lead you to where the O2 wires split off. I think they are all going back to the computer.

 

[Dborns]

It would appear the VSS wires run parallel with the downstream O2 sensor wiring. If you can't find the wiring for that O2 sensor I would think following the VSS wires would lead you to where the O2 wires split off. I think they are all going back to the computer.

I’ll trace all the wire looms down that side today and open them up to look for the correct wires.

Thank you

 

[Dborns]

I found the wires. I took a bunch of pictures at different areas and angles so I could look thru them today and see if I was missing something. They’re in a loom down on the frame by the T-case, and look like I tucked them either into the frame or on top. I don’t see a plug in the pic, but I’ll take a look tomorrow. I also have a new crank sensor showing up and I’ll bench test that for resistance before I install it. Both my old one and the 2nd one I installed read around 25(?) on the MM when I tested it for resistance which I’ve read numerous posts that it should be completely open.

 

[Dborns]

Well more frustration. I received the 2nd new crank sensor today and bench tested it for resistance. I was going by an old post I had found about testing the B and C pins on it and it should be open. It has the exact reading that the other two showed, around 25(?) with the MM set to 10k. I’m not even sure if I should take the time to put it in or not.
The next hope is tracing the downstream O2 sensors and finding they’re grounded out. If that’s not the case I have no idea what’s next.

 

[Dborns]

A couple more tests today. I plugged the new crank sensor in and probed the signal wire with the key on. I didn’t have 5v at the MM.
I also found the downstream O2 sensor and probed the signal wire on it. I didn’t have 5v there either.
So back to square one. I’m not getting the 5v from the pcm to anything.

 

[Dborns]

I tested the power to the PCM, and think I did it correctly. With the key ON, I probed the #1 terminal on the black PCM plug and got 12v.
I then probed #17 and no power.
#1 is the “ignition coil driver”, and #17 is “5v supply”.

Any suggestions on what goes out on the PCM to lose the 5v out?

 

[Dborns]

I also tested #2 and #22 and both have 12v.

 

[Anak]

I tested the power to the PCM, and think I did it correctly. With the key ON, I probed the #1 terminal on the black PCM plug and got 12v.
I then probed #17 and no power.
#1 is the “ignition coil driver”, and #17 is “5v supply”.

Any suggestions on what goes out on the PCM to lose the 5v out?

I would be inclined to ask these guys (or someone like them): WranglerFix (and yes, they deal with XJs too)

 

[Dborns]

I did some tests on the PCM and found I have 12v at all pins that should. I just don’t have 5v to any of the sensors that should be getting that. So the 5v from the PCM isn’t sending out.

 

[Dborns]

Update. I installed a 12v to 5v adapter at the ECM and now have 5v power. I replaced the coil. I found that I do NOT have 12v at the coil plug. I checked all fuses and tested the grn/or wire for continuity from the ASD to the coil plug and that’s good. I’ve tried two other relays in the ASD position. If I run a jumper at the ASD spot in the PCM, I DO get power to the coil but no start. I keep seeing that I’m supposed to hear a click or buzz at the relay when I turn the key on and I don’t hear that.
So something’s not allowing power to go thru the ASD relay. Is there something that should be grounding the ASD relay to make it close? Is there anyway to test that?
Any other suggestions?

 

[Dborns]

I worked on this more yesterday and stewed on it all evening trying to figure out what’s going on. The thing I keep coming back to is the relays.
The ASD relay has power to it, but won’t allow power thru it to go to the coil so I have no spark. So it’s as if the ASD is stuck open.
The fuel pump relay seems stuck closed because as soon as I turn the key to ON, the pump runs constant. Not the usual prime for a couple seconds then stop until the key is turned to start. I’ve switched all relays with others with no change.
I also have read I should hear a buzz or click from the relays when they operate which I’m not hearing that.
Any suggestions please!!