Help! Car ran today and now dead. No electric at all - short

[JohnB]

Help!

I need the lists collective wisdom. I drove my 260Z this morning to my kids hockey game. When I went to leave I turned the key and nothing. Dead silence. No hums, no fuel pump, no lights no radio...

I cleaned the poitive terminal which looked clean except for a little corrosion on the outside of the clamp bolt. the ground looked fine and tight. Nothing chaned when I tried to start it. I tried to jump it and I had a hugh arc that melted a spot on the terminal. I came home and searched the treads and the closest I found was a "Dead Short" in a battery. So I pulled a battery from my 240z that was on a charger and installed it. Still nothing. Then the ran came and I am home again with out the Z.

The Z was having a hard time with the starter each morning as it seemed to draw a lot of power to get it to start spinning. Once it spun the starter acted normally.

My Z is an early 260Z with a 2.8 short block and an E31 head and MSD electronic ignition. Electric fan conversion is about the extent of electric modifications.

Any ideas whoul;d be great,

Thanks,

JohnB

Chicago

[SteveJ]

I cleaned the poitive terminal which looked clean except for a little corrosion on the outside of the clamp bolt. the ground looked fine and tight. Nothing chaned when I tried to start it. I tried to jump it and I had a hugh arc that melted a spot on the terminal. I came home and searched the treads and the closest I found was a "Dead Short" in a battery. So I pulled a battery from my 240z that was on a charger and installed it. Still nothing. Then the ran came and I am home again with out the Z.

The Z was having a hard time with the starter each morning as it seemed to draw a lot of power to get it to start spinning. Once it spun the starter acted normally.

It sounds like you could have more than one problem here.

Missing data:

1. Age of the old battery

2. Age of the battery that was used as a sub

3. Did ANYTHING work with the old battery such as lights? This is without having the key turned on. You may have meant to say that, but it wasn't clear to me if you did.

Now for the random guessing:

Dead, dead, dead battery could be from age or a shorted cell in the battery or a bad fusible link. Do you use battery chargers or float chargers on your cars?

Huge arc when trying to jump start it could be from having the other end of the jumper cables touching one another (even through another piece of metal or you had your cables crossed. A shorted cell might also cause a spark.

Still dead with the new battery says that the new battery is old/shorted or you could have a bad fusible link.

Hard starting - Search over on Z Car for Ford solenoid. Tony D, a member on this site, has posted how to use a 6V Ford solenoid to overcome hard starting.

[JohnB]

I have had the car for two years and the battery was supposed to be new from PO. No idea if true. The swopped in battery is a 3-4 year old Optima Red Top. It showed a 80-90% charge on the battery charger after being charging for two days on a trickle charge. Most (all) batteries show this reading on my charger.

No lights or anything with the old battery. Everything worked this morning and last night. I went from having a car that worked to a car that acts like it has no battery. I will test the old battery Monday AM. The cables were not crosssed. I checked. It sparked when I hooked up the battery to the Z first and connected the jumpers to the positive on my Jeep and touched the ground of my Jeep body. It sparked/arched when I hooked it to the Jeep and then touched the Z battery positive terminal after connecting the ground jumper to the Z battery.

I drive the Z almost every day from April to November. Run it a few times in winter to keep the battery alive.

Where is the fusible link out side of the fuse box?

Thanks for the help,

JohnB

[IdahoKidd]

It sounds like a shorted starter. If it is worn enough, the thing will ground out on the inside and basically be a dead short to the positive side of the battery. Remove the main battery wire at the starter and temporarily connect all the wires that would have hooked to that terminal and then hook up known good battery. Everything should work but the starter. IF that works out, you'll need to replace the starter.

Another way to get a general test to see if it is a short is to disconnect the wires from the starter, put a jump cable lead right on the terminal stud, put the other end on an engine ground hook up the positive end of the jumper cable to the positive cable to a good battery and then just bump the neg cable across the neg post of the battery. If sparks fly, it is a short in the battery.

Of course both of these are "back yard" tests, the correct electrical testing tools should be used if they are availabe.

I'd bet the only two nickles I have left that it is a shorted starter though. Post a note when you find the solution.

Leonard

[manny1973]

It is probally the fuseable link. This is a wire located by the starter.

[IdahoKidd]

The fusable link comes into play once the power leaves the starter at the terminal. It is the resistance, the sparks, that tells me the hot circuit is coming into a ground somewhere. Now it could be a primary wire after the starter, but I am betting worn bushings are allowing the dragging starter issue he mentioned and now they are shorting out the armature.

2 cents worth less some change.........

Leonard

[JohnB]

I will start with the starter as it has been acting like it is on it's last legs, slow to engage and turn over. Are the standard starters for the 280ZX Tubo the gear reduction type?

Thanks,

JohnB

[JohnB]

Ok, so I replaced the starter with a new bosch high torq unit. No go. Nothing, notta. No lights, no start, no anything, just like a disconnected or dead battery. I am stumped. Any ideas would be great.

Thanks,

JohnB

[JohnB]

I am going to check out the fusible links.

[dimitri_zee]

Get a hold of a test light and probe the main cable from the battery to the starter. Make sure power is getting to it; you may have a bad connection within the main cable/terminal. With the light, check for power at the fusible links etc..Test light is a wonderful tool!

[SteveJ]

I am going to check out the fusible links.

Hopefully you have the FSM. If not, you can download it from Xenon S30.

Also if you don't know where the fusible links are, the attached picture should help. Don't forget to check the condition of your grounds, too.

[FastWoman]

Assuming the battery has voltage, the fact that your lights aren't working would suggest you have a fusible link problem. I don't know whether the lights and the ignition key circuit share a fusible link in the 260, but if so, then I think that might be it.

Try bypassing your fusible link(s) and ignition switch: Just clip a small wire to your starter's solenoid terminal, and touch it to the + post of your battery. The solenoid should close, and your starter should crank. If it will do this with the jumper wire but won't do anything when you try to start normally with the key, then you have an open circuit somewhere. It could be one of several things, including a fusible link, the ignition switch, or the connection to starter solenoid (i.e. small wire).

If the engine doesn't crank with the above test, then it's either your battery, your starter (not likely), or your battery cables. To narrow down a bit:

Try charging up your battery with a charger. If/when it shows it's been charged, test it with a volt meter. If you have maybe 13V, you're good. Even if you only have 12.25V or so, you have enough charge in your battery to test it. Now have a friend turn the key, while you continue to read the voltage. The starter solenoid should click if you have 12+ volts. If not, there's some problem with the solenoid or with the wiring or connections to the solenoid. If it clicks, then your starter should be engaged. Does your voltage drop to approx nothing? If so, then your battery is probably bad. Another test would be to turn on your headlights. (I know you say they don't work.) When you do this, does the voltage drop to almost nothing? If so, that's further evidence the battery is bad. Finally, run jumper cables from another vehicle. Now can you work your headlights? If so, the battery is almost certainly bad.

If the battery is good, but the starter won't crank, then test your cables. Start with the + cable. Attach the probes of the meter to each end of the cable -- the + probe at the battery and the common or - probe at the starter. Voltage should be zero. Now have a friend turn the key. If the voltage jumps to +12, then your cable is bad. Now hook the probes on the end of the negative (ground cable), with the common probe on the battery end. Repeat the test. A significant reading, higher than maybe a few volts, would indicate a bad cable. (I'm assuming at least SOME conductivity, because we're assuming your solenoid clicks.)

Now test your starter. Your starter has a big terminal where the battery cable connects, and it might have another large terminal where the solenoid couples power into the starter. If so, attach the probes to these two terminals, with the + probe on the battery side. Have a friend turn the key. You'll hear the solenoid click. Do you get 12V across these terminals -- exactly the same as at the battery? If so, your starter has an open circuit (bad). If the voltage is high, but less than 12V (which it should be), then the engine should be cranking. If the voltage is zero-ish, you might have a shorted starter.

Finally, you can take your battery and your starter to an auto parts store to have them tested. That might provide you some better answers.

Good luck! :-)