Engine bay harness
 

Has anyone ever replaced the engine bay harness? Looks like I might have to tackle this project. Any tips or things to pay extra attention to is appreciated

What’s wrong with yours?

Yes, but not on a 370z. Main harness behind the dash, Yes, several. It is not hard to do you just have to take your time and make sure you are plugging in the right stuff to the correct place. If you have no clue, you may want to get specialty Z to do it for you. No just any Joe blow fix it shop will cut it. I am just an anomaly. Give me a bunch of wire going everywhere and I am a happy man.

Not sure why you would want to replace the whole harness - that's a bottom-of-the-list option, IMNSHO - but the first thing I would do is try to acquire a Nissan assembly manual, if such a thing exists. I was able to get a set for a 1967 Mustang I had.

Most folks don't have the skill to troubleshoot a wiring harness problem. If I had to guess, a wire was pulled to tight and it has a break in the wire with the insulation in good shape. I have fixed many Nissans with this issue.

That could very well be it. The insulation looks good. Ive been getting the CEL every couple drive cycles, I end up removing and reinstalling the module and relays to get rid of the CEL.
It might be one of the contacts on the vvel or relay pigtails.

Plug in your OBDII and clear the codes, leave it hooked up and go around and wiggle the wires in the loom. Watch for the code to pop back in. It is best to have your scanner where you can see it in the engine bay. When that happens, you are close to the area with the problem. Double check the area by doing it a couple of times. Break open the harness and look for the correct colored wire. May need FSM to get the proper color and tracer color. Put the wire between 2 finger nails and slowly go down the wire with a little pressure. If you feel it catch between your fingernails and collapse, do it again. You will see all that is holding it together is the insulation. Cut the wire there and fix it. You choice, barrel connector or solder and heat shrink. I have fixed a many a chronic check engine light issue this way.

Why not all three? I don't do it often but have been known to crimp an uninsulated connector, solder it, and then heat shrink. Saves a little space without the insulation on the crimp connector and the wire will break before it pulls out of the connector. But, yeah, that's overkill in a lot of situations.

Ill give this a shot. How do I troubleshoot to see if its a bad pin connector? I tested the vvel connector for power, but not sure about the relay, also as far as the female side being too loose (insert jokes here)

Only thing you can do is insert a pick into the back and make sure the connectors are clicked into the casing. You can look at where the connectors are to ensure you see the female connectors. Don't make a mess out of it.