engine won't turn over after disconnecting negative
 

After months of seeing people having problems and everyone here on the org help them with it, it's finally my turn to join in on the ..fun.

I was putting a new head unit into my car and disconnected the negative from my battery just to be safe. When I took it off I simply lifted it off and placed it to the side, didn't pull on it or anything. Took care of the radio, put the negative back on, and my car cranks semi-weakly but won't turn over. Luckily I had someone else there with me and with a jump the car started right back up.

I cleaned all of my terminals, although they were already in pretty good shape, just to be sure that wasn't it. The car still won't turn over on its own, but with a jump it starts right up and runs fine. If I run it and then shut it off and try to restart it, usually it works the first time but then if I turn it off and try again it will be back to cranking weakly, seeming like it isn't holding a charge or something.

I'm thinking it may be a bad ground as that is the first time I have taken my negative wire off since I got the car in July. The main battery ground is looking pretty gross and the wire probably isn't in the best of shape, I just haven't had time to look at it yet.

Any ideas on what I can check? Let me know if I can add any extra information to help you guys troubleshoot.

EDIT: Just thought of it, doubt it would make any difference but might as well add it, when putting my dash back together I forgot to plug in the 3 climate control harnesses in an excited rush. I obviously plan on plugging these back in when I get a minute but I just didn't know if that could be a quirky reason for something not working.

clean the grounds.

plug in climate control harnesses.

check battery voltage engine on and off.

what should the voltage be at, on and off?

i forgot to plug in the climate control harnesses when i replaced my mom's head unit. that shouldn't affect anything.

12.5v off 13.5-14.2 on
How old is the battery?

When I LED'd my gauges I decided to take the trip with them out of the dash the car then almost died I plugged everything back in and it was fine all the circuits in the dash I think are essential for completeing all the charging circuits

could be your alternator. ive seen this happen several times. install a new electronic equipment and the alternator goes.

was it acting up before the install??

I had this issue when I first got the car. The next day it wouldn't start. I got a jump and it turned on but wouldn't turn on on its own. Long story short I cleaned the post and made sure they were on tight. Cranked right up. Try that

unscrew it and screw it back in. Also if you continue to follow that negative cable, it should connect to a metal part of the engine. Unscrew and screw that one in again as well.

By unscrewing and screwing in those bolts/nuts, you are dislodging any rust that's probably developed there. If you're really hard core, you can take a metal tooth brush to polish up the bolts/nuts to clean them up. For the holes they screw into, you'd need some sort of metal pipe cleaner but a small screwdriver could do some basic scrubbing.

Usually the ground connections to the body get rusty as hell on these old cars and the engine connections aren't as bad.


DW

Check the battery terminal itself that it is tight and solid. If you can wiggle the battery terminal, the battery needs to be replaced. Also a possibly bad battery cable.

sometimes it would take a little long to crank if it had been sitting but would always turn over eventually. The terminals are tight and I sanded them down as well as the terminal clamps that connect to the posts. I'm gonna hunt down the grounds and clean everything up on that end and hope its that and not my alternator.

Start with the simple/obvious things first. Check, your battery.

Am I wrong or wouldn't you normally want to disconnect the positive terminal when storing or working on the car ? Also, I agree that it sounds like a simple weak battery issue that changed a little after removing the terminal.

Because all cars are based on a negative ground system, meaning that every metal part of the car, body and engine, is at the same potential as the negative terminal of your battery, you always remove the -ve terminal.

Let's say you remove the +ve and work on your car. Then by some accident you have this long wrench or metal tool accidentally touch the +ve battery terminal and the other end of that tool touch any metal part of the car. Bam, you have power because you have just completed the circuit.

With the -ve disconnected and you have that same accident, nothing happens because the circuit is not complete. The -ve terminal removal makes the whole body and engine dead, electrically.

DW

I wasn't even at 11 volts while off and running I was probably on the low end of things but it looked it was close to almost being at 14. Does this mean I may just need a new battery? Also, does this take things away from being my alternator because running it was at a decent voltage?

yes to both questions. Your battery should be 12 volts when the engine is not running. Since the battery is below 12, it has a problem. When the car is running, the voltage was at 14 which says the alternator was trying to charge the battery.

Your alternator is working fine. Replace the battery and your starting problem will be gone.

Yes, it is likely your battery. You can go to the parts store and have them test it but you may be stranded if you don't have a jump. Cleaning the posts and all connections is a cheap way of checking things out but since it won't start on it's own, but starts fine with a jump that generally points to the battery. Once it is started the alternator takes over, that's why you have nearly 14V with it running. When you have a bad alternator with a good battery, the car will start and run until the battery drains and then it dies. With a good alternator you can theoretically start the car, pull the battery and drive until you turn it back off.

Google "Advanced Auto Parts Coupon Code" and buy your battery on their website with in-store pickup. I saved $30 on my battery a couple weeks ago doing it that way.