Car won't start - battery won't accept a jump

[DevinB]

It's not a off-road rig, sorry, so mods, if you must move it, so be it. Anyway, it's a '84 Nissan 300ZX. Last night I'm at the grocery store and it won't start, acts like it's a dead battery, ie dashlights are dim, no clicking from the starter even, just no juice. I jog home, grab the wife's car, try to jump it after cleaning off the terminals and such, and it still won't start. It seemed like the battery wouldn't accept the charge or something. But if the jumper cables are attached to the posts, then it should still start up, regardless if it's a dead battery, right? So we end up push-starting it. I drive it around for a bit, get it home, turn it off, try it again, and nothing. No charge. So this morning I have to push start it again to get to work. Try to start it again once at work, nothing. Would this be a bad alternator? Bad battery? Bad battery wires? Thanks for any help.
Devin

 

[81Ramchargerman]

I am no mechanic, but if your alternator was dead, then the car should only run until the battery is drained...then it should shut off...correct?? Bueler?Bueler?

 

[Pathos]

You could use a multimeter to check the battery for charge .. or take it up to someplace that does free battery testing, thinking autozone does this. If the battery is good then check the connections, are they clean and tight. Next up would be the solenoid, which i believe is attached to the starter on the old Z cars. To check if its the problem you could just bypass it and run power straight to the starter in SHORT bursts, like tap a screwdriver across the terminals. The relays would be another thing to check.

 

[00harpdawg]

battery

i had this exact problem with my jeep and it was the battery if you take your battery down to pep boys or autozone they can tell you if it's bad as soon as i replaced the battery it ran great hope this helps

 

[Spork]

Could be the battery but I would look at the battery cables, and clean the posts too just to make sure.

 

[H-K]

I am no mechanic, but if your alternator was dead, then the car should only run until the battery is drained...then it should shut off...correct?? Bueler?Bueler?

I think this is usually the correct diagnosis, however (somebody correct me if I"m wrong) the alternator can still function at a level that will provide spark, but not enough juice to recharge the battery. I had an alternator go out on an old Firebird of mine and it would run, but the headlights were dim (varied with RPMs) and the battery wouldn't charge.

If you were able to compression start the car, but were unable to jumpstart it, then this might tell you something. If the problem was just a dead battery, you should still be able to jumpstart it. Are you confident that you had good connections with the jumper cables? ...and the car runs fine once compression-started? If so, I'd say there's something wrong somewhere between the battery terminals and the starter -- ie. the battery and/or alternator are probably not the culprits.

 

[mbryson]

........... Are you confident that you had good connections with the jumper cables? ...........

Huge issue there. Most jumper cables I've looked at are pretty wimpy nowadays.....

 

[closhedbb]

Bad Starter Motor?

It sounds to me like it's the starter motor. Though this wouldn't explain why the battery was dead, it would explain why the car wouldn't start even with a good charge, but would run when push started. I had a Civic with the same problem, it just wouldn't do anything when I turned the key even with a good battery, but would jump start just fine and run after that. If it runs after you push start it, then the alternator and battery must be working, or you wouldn't get fire.

Just go to an AutoZone or Checkers or Pepboys and pick a new starter motor, exchanging it for the bad one. It's an easy DIY half hour project with a ratchet and will likely solve the problem and probably won't cost you more than $80-$120

 

[closhedbb]

As far as the alternator goes, if it goes out, the car will run as long as the battery has charge, then it will cut out. All electrical systems run from the battery which charges from the alt.. A bad battery or a bad alternator would make the car undrivable even with a push start. If your lights are dim, then the battery is dying and certainly wouldn't have enough juice to start the car, unless you're lucky. But if it runs well after the push start, then your alternator is probably okay. It sounds to me like you may have not only a bad starter motor, but also a weak battery. When you are driving the car, do the lights become brighter? If they go back to being dim after you're done driving, then it's the battery that's not holding the charge. Your alternator has nothing to do with getting the car started, but once it gets going, if the lights get brighter your alternator is fine. Your alt. could be bad or weak, but that wouldn't explain the car nto starting when hooked up to a good battery.

Diagnose the starting system in this order:
Starter motor
Battery
Alternator
Wiring

 

[H-K]

As far as the alternator goes, if it goes out, the car will run as long as the battery has charge, then it will cut out. All electrical systems run from the battery which charges from the alt.. A bad battery or a bad alternator would make the car undrivable even with a push start. If your lights are dim, then the battery is dying and certainly wouldn't have enough juice to start the car, unless you're lucky. But if it runs well after the push start, then your alternator is probably okay. It sounds to me like you may have not only a bad starter motor, but also a weak battery. When you are driving the car, do the lights become brighter? If they go back to being dim after you're done driving, then it's the battery that's not holding the charge. Your alternator has nothing to do with getting the car started, but once it gets going, if the lights get brighter your alternator is fine. Your alt. could be bad or weak, but that wouldn't explain the car nto starting when hooked up to a good battery.

Diagnose the starting system in this order:
Starter motor
Battery
Alternator
Wiring
HYPERDRIVE
FLUX CAPACITOR
IMPROBABILITY DRIVE
DILITHIUM CRYSTAL
MR. FUSION REACTOR

Hmm...If you disconnect a battery while the vehicle is running, would it continue to run or would it die? I always thought a vehicle would run without being attached to a battery.

If you're travelling in your vehicle at the speed of light and you turn on your headlights, does anything happen?

 

[closhedbb]

Nope, if you disconnect the battery, it will not run. The alternator couldn't power the vehicle because the power it generates fluctuates as the RPMs change, that and disconnecting the battery severs the connection, so it's no longer connected anyway.

I would imagine that as you approach the speed of light, the light energy would build up just like a jet approaching the speed of sound, and like sound, at the speed of light, the energy would be dumped in a photon boom. At least that's what happened when I did it, but varies from Jeep to Jeep... :greg:

 

[waynehartwig]

A completely dead battery is difficult to jump start. Especially if said battery has a shorted plate or two inside.

Perfect example, I was up in Boise a few weeks ago and everyone loaded up ready to go on a trail ride, and one of the guys realized his kids left his key on all night and killed his battery. No problem.. Pushed it out to the street and hooked it up to his f250 pickup to jump it. No go.. It would just click, nothing else. So we took the opportunity to have another cup of coffee and oogle rigs. Tried again 30 mins later, same deal. I pulled out my handy dandy jump starting battery and it fired right up. Driving it from his house to the trail head didn't charge the battery and his alternator wouldn't put out enough juice to keep the cooling fan on to keep the motor cool... So he was out, drove back home thinking his battery was toast. He ended up putting the battery on a trickle charger all day long and by that evening it was fully charged and started like a champ!

So.... You might have two things wrong right now, a weak alternator and a dead battery. Try putting the battery on a charger (trickle) over night and see what happens. If she takes you to work in the am, then you have a bad alternator. If she doesn't, get a new battery.

 

[DevinB]

If you were able to compression start the car, but were unable to jumpstart it, then this might tell you something. If the problem was just a dead battery, you should still be able to jumpstart it. Are you confident that you had good connections with the jumper cables? ...and the car runs fine once compression-started? If so, I'd say there's something wrong somewhere between the battery terminals and the starter -- ie. the battery and/or alternator are probably not the culprits.

You win the Twinkie. It was a bad connector. After putting a new battery in, it still wouldn't do anything. So we put the actual bare positive wire, before the connector, on the positive post and it fired right up. So we left the battery unhooked (yes, we ran the car w/out a battery) and drove to Checker where we cut the old positive connector off, cleaned the wires some, then slapped a new connector on and she purrs like a kitten. Well, knocks, actually, cuz she's low on oil. Anyways, thanks for the tips. I'm glad it wasn't anything more. It kinda sucks that we spent $60 on a new battery when all it was was a $2 connector, but the old battery was past its prime anyways.
Devin

 

[Spork]

Man somebody should have just recommended you look at the cables...

 

[H-K]

Man somebody should have just recommended you look at the cables...

Well, we kinda did. When I said the problem was somewhere between the terminals and the starter, I wasn't talking about the air in between

 

[onetuff76]

If you're travelling in your vehicle at the speed of light and you turn on your headlights, does anything happen?

To answer your question the speed of light is constant. So you inside of your car would measure the speed of light to be c (roughly 3.0*10^8 m/s), but someone outside of your car would measure your headlights at c and you in your car at .9999c. But this is all relative to your reference frame you choose to make your observations from, but the speed of any light emission will remain constant through any reference frame.

 

[H-K]

To answer your question the speed of light is constant. So you inside of your car would measure the speed of light to be c (roughly 3.0*10^8 m/s), but someone outside of your car would measure your headlights at c and you in your car at .9999c. But this is all relative to your reference frame you choose to make your observations from, but the speed of any light emission will remain constant through any reference frame.

I should have stated that It was relative to the operator's observations.

It's actually a quote from Steven Wright (comedian). He said he went in for a job interview and the interviewer asked him if he had any questions, so he asked "If you're driving your car at the speed of light and you turn on your headlights, does anything happen?" The interviewer replied "well, um, I don't know" to which Steven replied "Then I don't want to work here".

/dry

 

[DevinB]

Man somebody should have just recommended you look at the cables...

Fine, you can have a Twinkie too... :greg:
Devin

 

[H-K]

Fine, you can have a Twinkie too... :greg:
Devin

I'm not sharing mine. You'll have to give him his own.

 

[Spork]

Yummy got love twinkies