I have a 1985 Nissan 300zx turbo. I was driving down the highway and noticed traffic coming right up behind me before they slammed on their brakes. I pulled over and noticed the brake lights were not functioning. When I shut the car off and went to restart, it didn't turn over. The battery was completely dead. Before I stopped the car, I had noticed the stereo had been turning on and off like there was no power to it. The digital gauges kept turning on and off also. I got the car home and replaced the battery with a yellow top optima, replaced the alternator, and the battery cables. I got the car running, but when i revved the motor everything digital in the car went out. The engine kept running. Almost like everything from the fire wall back didn't work. I would turn it off, then back on and the gauges would then work again. I'd rev it and same thing until after a while, nothing worked at all. Any suggestions or help would be greatly appreciated because I want my Nissan back again. Thank you.
Check the battery voltage with a multimeter while the engine is running. Rev it up and down and see what the meter shows.
With the key off, check the resistance between the negative battery post and somewhere on the engine, such as the plenum. More than a few ohms resistance is suspect.
Check the resistance between the negative battery post and an earth point on the body. As above.
Does your new negative battery cable have an earth point to the body as per stock?
this is how your ground strap is supposed to be grounded before it goes to the starter as noted by Mr T. If a po cut off that crimped piece of copper and went direct to starter that could well be your problem. Have you checked your fusible links - another favorite place for electricity to dissappear. for those not familiar with limey slang earthing is Brit for grounds to us yanks. the one size fit all battery terminals are another place to have electricity go haywire. The fact that it kept running however would indicate fusible links but if you have the other problems fixing them now will be a boon in the future.
I dont know if i had made the battery ground to the body.. I do think i have it grounded to the starter. Im currently in Afghanistan but Im having my wife take pictures of it to send to me to see if i had done it. I will let everyone know on the findings when I get the picture. Thank you everyone for leading me in the correct direction with this.
I had an issue almost like yours. And I had replaced the battery cables, the alternator, everything. And just to check, I had the old alternator tested. It was in perfect working order. Then I replaced the belt for it. The old belt had been so worn out it turned to a plastic feeling thing with saw teeth. That was the dumbest thing I had done with that car. Check the belt. It could always be something that simple.
If it were me I would find a wiring digram for your car and start at the battery doing voltage drops. Dont forget to check the grounds that are linked to your car and block. If one of those grounds go bad, get too much rust or some **** like that it might cause these problems.
i have had this problem also its most likely your fusible link (look to the set of i believe 4 links right next to your battery) it should be the one with i think black and white wires connecting to it at the bottom that link controls your dash, lights, turn signal, radio, practically all electronics in the car