First Off, Good evening.

I realize this may be the wrong forum, and i apologize. I wanted to post under engine and drivetrain but the only other forum which seemed plausible was VQ35HR.

Ive been posting to these forums for the past year or so regarding electrical issues my car has been having, resulting in the vehicle not starting.

2003 350z AT 65k miles

About 18 months ago I had a bad alternator ground. Brake/BATT light came on for a while, was found to be the harness ground going to the fuse box next to the battery. A Local shop ran a separate wire along the harness essentially bypassing the harness ground for the alternator to the fuse box. 6 or so months later the vehicle would intermittently take a little while to start, as if the starter was going. No other issues really indicate it may be the starter. Got it started the last time I drove it after jumping it twice and had a CEL for a bad ECU. After today with the help of some locals ive come to the conclusion of removing the "bypass ground" and repairing the harness ground. If the harness ground is not salvageable, than ultimately replacing the entire harness (and eventually replacing the harness regardless).

Is it plausible that this may have fried my ECU?

Im assuming I will need to reprogram my keys, is there anything else I should consider checking/replacing? BCM? Ive been having issues with the passenger side door (locks?) clicking as well as dome lights not functioning properly..

Just looking for some insight from anybody who may have gone through this before really. I know I will need an exact match on the ECU, same year same AT same trim. Just trying to gain as much insight as possible, and I still have to fix the ground issue before I fry another ECU anyways. Im going to start on the ground wire in 2 weeks, taking this time in between to research the issue and make sure im not missing anything.

Please, im open to any and all advice.

And in the meantime I still gotta find where the ECU is located

Update: Videos 7/31

 

I don't believe the ECM has a direct line of current going to it. There is a relay in between. So any spike in current beyond the amperage rating of the relay would compromise the relay before reaching the ECM. The relay is located within the IPDM in your battery compartment. Try replacing that as a first step.

 

I have replaced it. Also spoke with a ECM/ECU Shop and they feel that my problem is not consistent with ecu/ecm failure and I should likely start with the bcm.

Ive posted about the issue here before as well as reddit and various locals and nobody really has any idea why the problem may be.

 

I apologize, my last comment sounded almost rude and unappreciative! I did not mean it that way in any sense. You've all been extremely helpful in eliminating possibilities and giving me places to start, I've been passively working on the issue for a while now but t hasn't received my full attention and it seems to boggle any and everybody I ask!

 

No, it's cool. I didn't take offense. You gave me a concise answer, like I prefer... Anyway, did you consult the Factory Service Manual and perform the ''Fuse and Fusible Link Inspection", the ''Power Supply Circuit Inspection", and the "Ground Circuit Inspection" for the BCM? If not, I would try that next... http://www.nicoclub.com/service-manu...coupe/2003/bcs

 

Will do that and post back in a few weeks. I apologize, i just started a small business and it keeps me pretty busy, as does a friends wedding and a brief (3-day) trip alongside my full time job. I will also sand the paint on the negative ground to the body from the battery and see how that goes.

 

Also, this is the thread I made a few months ago in regards to the same issue with a bit more detail

https://my350z.com/forum/maintenance...n-t-start.html

Edit: Videos added

 

I have an ECU I could sell you from an 03 auto Z... Hmmmmmm maybe I'll read the rest of this now.

 

I also have all the factory harnesses and everything, well I basically have your exact car sitting in my driveway being parted out... Check the market place section if you need anything...

 

You know whats funny? Earlier today I did a search for "BCM" and it brought up a thread on a guy trying to sell his salvaged 2003 350 for more than $300, and as I was reading I was thinking to myself "This guys in Boston, not too far it might be worth throwing him a better offer and towing it home..."

I continued reading, and saw you grabbed it

I may have to take you up on that. Youre fairly "local" as im in Central CT, about a half hour south of Springfield, but first I just need to figure out what parts I need In all honesty, a harness is a pretty big job for myself...

 

Well keep me in mind if you need anything I'm right by six flags New England so we are pretty local...

Im in no hurry to sell any of that stuff, im hoping someone buys the engine and I can just keep it runnable till they do... Car is half taken apart at this point though.

 

Thanks, will do. In the meantime, any idea on parts i may need/where to start with my current issue? A few people have been steering my towards BCM, so i may be interested if you have one but i think (correct me if im wrong) trim and production date play a role in compatibility on that one...

Im really at a loss and looking for somebody whos had similar issues before.

 

After watching your videos.....

I honestly think your battery is dead.

 

lol.. Mike's soliciting every thread now.. Smart.


Didn't get a chance to watch the videos after they were put in, can't watch them now either... That would be some **** if it was your battery.

 

the videos didn't work for you?

also, I've since then tried 2 other brand new battery's from 2 separate manufacturers. No dice. I also ran the requested tests in the thread I posted a few months ago, as well as having ha don't charging system tested. Everything came back "good" :/

 

I just can't open videos on the computers here at work. I can on my phone , but I only have one bar in here so it takes forever. I usually just hop on here and do my thing between servicing vehicles...

 

Haha thats what I do

Does the car have an auto starter? Or an aftermarket alarm system? It honestly sounds like when your battery is dead and your car is trying to auto start...

 

ahh okay thought it was an error from something i did.

None. Battery currently on a trickle charger. Here is an updated video taken maybe a half hour ago. Key Fob is acting normally, no more taillight flicker/subtle horn sounds. I ran a jumper cable from negative to engine and upon trying to start no dice but the rear windshield wiper made 1.5 passes or "swipes" wiith the rear wiper set to "off"

 

Your car is possessed, I got all the goodies just figure out what you need lol.

How is the connection between the battery and the starter? I would make sure that is good... Would also beef up your ground if your still just using the stock ground add a few more for good measure...