car dead - stuck at work

[AnthonyG]

drove to work fine this morning. went out to start it to go to lunch and nothing.

volt meter initially read fine. tried to start and it went straight to 0

i have checked battery and fuses. batt at terminal reads 12.5, fuses are all ok, fusible links are as well.

now when i engage any light (turn on headlights, brake lights, interior dome light) the voltage halves on the dash voltmeter.

removed all light related fuses.

still not turning over.

any suggestions what it could be?

any suggestions as to what to try next?

car is a 1976 280z, FI

thanks

[steve91tt]

My guess is a bad battery. Sometimes they can show a 12v surface charge but have no ability to supply the amps to run the car.

[steve91tt]

If it is a bad battery you may be able to jump start it to get you to autozone for a battery test/new battery.

Good luck!

[AnthonyG]

would the relay click but not allow the engine to turn over with a weak battery?

I have a voltage regulator that is about a year old, so it probably isn't that.

if i have the lights on the dash voltmeter goes to 0. if the battery is dead then would it make sense that it would then read 0 at the battery terminals as well?

(im thinking about tests i can do. and yes I do carry a multimeter with me. its in the box with the the FSM, and other spare parts)

i could use the luck.

what really sucks is a groundhog chewed through the fuel line on my daily driver. that part is coming today or tomorrow.

[spitz17]

Sounds like the symptoms of my bad battery a few months ago!

[steve91tt]

if i have the lights on the dash voltmeter goes to 0. if the battery is dead then would it make sense that it would then read 0 at the battery terminals as well?

Could it be a dirty battery terminal? Sometimes they look clean but there is enough oxidation between the post and the lead to cause the symptoms you describe if you are reading voltage with you multimeter from the posts.

[AnthonyG]

terminals are clean. start of spring i cleaned them and the battery with a wire brush. tested continuity from terminal to further along the wire to check that. I'll try jumping the car before calling the tow truck. thankfully i invested in AAA+rv, and I live only 30 miles away.

[steve91tt]

terminals are clean. start of spring i cleaned them and the battery with a wire brush. tested continuity from terminal to further along the wire to check that. I'll try jumping the car before calling the tow truck. thankfully i invested in AAA+rv, and I live only 30 miles away.

Sounds like you have got the terminals clean but for future reference the continuity test will not show a dirty lead as the crud on the posts generally lets enough current through to fool the meter but not enough to turn over the engine. High current load applications like a starter can be hard to diagnose.

[Walter Moore]

If you can get the battery to a parts store they can test it for you.

But that does sound like a dead battery.

[Earthcruiser]

I had the same issue with my Jeep a couple month back. Turned out to be the solanoid on the starter. Worth a check.

[AnthonyG]

update - it appears more that a battery. jumping it did nothing. changing it out did nothing. i ended up towing it home. Looks like I have a long sequence of troubleshooting. I know i shoudl be upset, but I'm looking forward to the challenge...

more info - when attempting to jump start, it appeared that the air conditioner compressor was trying to kick in (clutch clicking). no belt to it anymore and shouldnt have been trying. may have been that system fouling up everything. it is an aftermarket system tha has never worked since i got the car, so it may be time to strip it out rather than try to fix it...

either way the symptoms shout short at me, so I won't feel confident until i've checked every bit of wire. probably easier to just get new wire.

thanks for everyones suggestions.

Just because it isn't easy doesn't mean it's not fun.

[73 240Z Man]

I agree... Bad battery... prob left something on. Dome light, etc.

Bump start it and drive home... Don't shut it off until you are home. It will prob start when you get home but I would have it tested. Autozone will test it for free.