I messed up my z31 help please
 

Well last week I went to my z31 and tried starting it and it wouldn't start I tried push staring it and didn't work when I opened the hood I realized that my spark plug cables 1,3,5 from the distributor cap were disconnected since then my z lost all power but if I wiggle my negative battery cable the power comes back but when I crank it just clicks and loses all the power then I grab my test light put it to ground and touch my batterys negative post and it has power it lights up which is not right but again if I wiggle the black battery cable the power comes back to the car and positive battery post , someone please help why does this happen and how can I fix it

Hi Walterz31,
Welcome to the forum. With the 1,3,5 spark plug cables being removed from the distributor, with the way your describe this, did someone else pull these off?
The wiggling of the battery negative cable tells me there is a break in the electrical connection. Could be a broken cable, a loose terminal on the battery (most probable cause) or a lot of corrosion on the battery terminal/cable connection. First thing to do is to take off the Negative battery terminal and clean it up. The rule is when taking cables off a battery is: NEGATIVE TERMINAL IS ALWAYS THE FIRST ONE TO BE TAKEN OFF, THEN THE POSITIVE CABLE CAN BE TAKEN OFF. WHEN PUTTING THEM BACK ON, THE POSITIVE CABLE ALWAYS GOES ON FIRST, THEN THE NEGATIVE CABLE. You could do damage to the cars computer, if you do it in reverse. If there is a whitish or greenish powder material around EITHER battery post, then get some baking soda and mix with a little water and pour over the terminal. At a auto supply store you can pick up a battery terminal cleaning tool. It has a wire brush on one end for cleaning out the inside diameter of the cable end and a wire brush inside a tube which you push down over he battery terminal and twist to remove corrosion and get to clean metal. Then put on a little di-electric grease to help stop future corrosion and make sure the cable ends are put back on in the correct sequence and tighten them up. Let us know what you find out. Thanks,
Bob

Hi Walterz31, Being a new member, there was a message sent to you which describes what to do on the forums.
After you log in, there will be a line that comes up that looks like this; (See attachment below). Then cClick on "PRIVATE MESSAGES" and open up the message from the forum moderator. This part is usually overlooked by new members. I know I did that initially. It has great information.


Here are a few pictures of some tools to have; A battery post and cable clamp cleaner, Dielectric grease, 2 types of electrical meters. either one will work for you. Digital is on the left and an analog is on the right. You can purchase a base model or a very expensive one to check the DC voltage of the battery and whether you have open or closed circuits (These 2 tests are the most popular uses for a beginner).


Also now that you have your battery out of your car, take your battery to an Auto parts store, like Autozone or OReillys and have them "Load Test" your battery to confirm it is in good shape. The cost is FREE to customers as a service to them. Then put your tested "GOOD" battery or a new one back in and follow the install sequence I mentioned in a reply up above and try it again. Let us know, Thanks, Bob

better off with a spray on corrosion inhibitor. Dialectric grease is an insulation medium meant to be used on the outside of insulators. Why does everyone insist on using it to insulate things that are meant to conduct electricity. like inside the plug on a maf connection and the like. look up the meaning of dielectric. https://en.wikipedia.org/wiki/Silicone_grease

if someone removed the original battery cables or put those one size fitall clamp on pieces of sh*t it is a problem you don't want. original z31 cables had a copper square crimped about 3-4 inches from the negative terminal. it was secured to the body with an M8 bolt into the body a little below and to the outside of the M6 bolt that secured the battery hold down bar. if you don't have a hold down bar find or make one. a battery that slides around is another gremlin you don't want. If you don't know what M8 or M6 means you probably ought to learn about ISO fastener specs.

A good battery shop (ie not Walmart or sears or oreilly's) can make up a decent set of cables fairly cheaply that has actual lead sealed terminals. Cost me less than $20 to rehabilitate the ones on my 86T
but you have to be able to tell them what you want.

which of your practical joker friends unplugged the wires??? Mighty strange that you just opened the hood and found that out. I'm assuming from your post that the car was running at one point.

to answer your question about fixing the problem I would suggest you learn electricity 101 and then get the fsm from xenon and READ IT.

I pulled the cables out and forgot too pit them back and tried starting it without them

And I'm sure there is no corrosion on the battery cable the thing is that I have power on my negative terminal and not on the positive which causes the car to have no power but if I mess with the negative cable the power goes back to normal to the positive terminal but when I go to crank the car it just clicks and all the power goes out and the problem repeats with the negative battery terminal having power which causes the car to have no power

WOW, I can sure see why part of your name is "GRUMPY". I would like to know how many new people to the forum you have turned off and have not come back. Over my 43 + years of working in the Paper industry, with many individuals who felt they knew more than others, and had no patience with younger people learning their way, would get angry and make others feel belittled. Keep up the good work!!!

"It can be applied to the actual contact as well, because the contact pressure is sufficient to penetrate the grease film. Doing so on such high pressure contact surfaces between different metals has the advantage of sealing the contact area against electrolytes that might cause rapid deterioration from galvanic corrosion"


Exactly what the cable connectors and the lead posts on a battery see and a "little dielectric grease", not an over abundance, can help!

Hi Walterz31,
I understand your frustrations. I also know you are trying to do things for yourself. That is commendable.
Using a test light is not going to tell you what the voltage of a battery should be. A fully charged 12 volt battery should be around 12.5 volts. You can have a lower voltage and it will not start a car and you will hear the solenoid "clicking", but it would light up a test light.. The proper battery voltage is required to pull in the starter solenoid, to turn the starter and have enough torgue to turn over the engine. Let us know what voltage your battery tests at. Thanks, Bob

My battery is fine you don't get what I'm saying ! My test light should not light up when I touch it to the negative battey terminal and it does !! That's not right
It should light up on the positive battery terminal but when I wiggle the negative cable the power goes back to the red terminal that's how it should be but when I crank it , it just clicks and the power is lost

From your original post you stated "...........then I grab my test light put it to ground and touch my batterys negative post and it has power it lights up which is not right but again if I wiggle the black battery cable the power comes back to the car and positive battery post,......."
I understand what you are saying now. My apologies to you and my respect for not giving up on your efforts.
NOW, let's start over.
There must be a short somewhere. I will get back to you a little later. Thanks, Bob

The following attached pictures and Starter electrical schematic is for a 1984 300ZX. I believe it is the same for a 1985, but you will need to get a copy from the Factory Service Manual to confirm. As you will see on the electrical schematic, it shows both the manual transmission and the automatic. In the right corner of each section there is a "LEGEND" that gives which wires to follow depending on if you have: (T) With Turbocharger models, (NT) Without turbocharger models, (TH) With theft warning system), and (THL) Without theft warning system. From this you can also understand why it is so important to get a FSM and to let others know on the form, exactly what options you have on your car (For future reference). There really isn't much in the starter system. The negative cable attaches to the battery, then, as the picture shows on my car, a flange on that wire bolts to the firewall, then the wire goes down to a junction box, and ends up being attached to the anchor bolt, under its head where it bolts through the bell housing. This grounds the starter.
There is a second wire that goes into that same junction box, it is a power wire, from the + terminal of the battery, that goes down to the "magnetic switch assembly" (solenoid), that is attached to the top of the starter. This wire goes to the top bolt on the solenoid. The wire coming out of the starter goes to the bottom bolt on the solenoid and there is a Spade connector with a yellow wire that goes to the 3rd connection. As you will see on the condition of all wires, on my car they were extremely dirty and corroded. They were all taken off and cleaned, as I am restoring this car for my daughter and Son-in-Law. Somewhere there is a short in the wiring.
I would suggest first, that you download a FSM and second, check all the wiring connections for loose bolts and clean them up. The one on the firewall, and those going to the bolt on the bell housing and the starter Solenoid as shown in the pictures. This would be "looking for the obvious" than starting with the 'Harder" things. Let us know what you find out..
Thanks, Bob

This afternoon I took apart what I mistakenly called the "junction box". It is actually an insulated bracket to hold the positive and negative wires rigidly against the frame rail. The large rubber piece is to insulate the 2 wires from coming into contact with each other. It might be possible that one of the wires has had the insulation rub through and is causing a short to ground. You might want to check this out.

Help
 

Bob, where does the giant ground clip showing in pic 5 by the steering rack go? I will be eternally grateful if you can help.