5mo ago

Question for the mechanics of Lemmy; what is the most likely problem?

So for the past ~two weeks I've dealt with the clamp that goes around my negative post had been slipping off of the post. Today before work(seems to be only when you have somewhere to be) I went to crank my car, to hear a single click but no start.

Now, the lights come on, AC goes full blast, and the headlights and radio work. I jumped the battery from my wife's car with no luck.

Based on this, could you give me some ideas/options/advice on how or what to fix/check? I have minimal tools and virtually no mechanical knowledge.

Any and all help is appreciated. Even if it's just a "damn. That sucks."

Video update. Yes I knowy car is dirty.

Didn't know this community existed but in case someone else needs it later: https://lemmy.world/c/mechanicadvice

29 comments

I'm going to guess the battery. It's also the easiest place to start investigating. Everything else can still come on even if it doesn't have enough power to start the car.
How long are you leaving your jumper cables attached before trying to start it? Jumping can take at least a few minutes to build up enough charge.
How old is the battery? There's usually a month/year of manufacture sticker on it. If it's 5+ years old, there's a good chance it's due for replacement.
Is the negative post connection tight? There isn't any good reason the cable should be slipping off the post. Loose connection could also cause the car not to start.
- I'd like to add that batteries might only last 3 years if you live in a cold climate.
  
  I live on the back of the devil's nuts in SC, USA.
- While jumping in left it for around five minutes and revved the wife's car twice during that. The same symptoms persisted.
  I'm not sure about the actual age of the battery but I don't believe it's more than 5 years yet.
  I'm almost positive the contact is loose. My solution after it had been slipping off was to push it back down the post with a hard rubber keychain I have. I'm hoping that's it and I just need to tighten it as that's the cheapest fix.
  
  The battery needs to be able to deliver 100+ amps in an instant.
  A battery can fail in a manner where it’s not longer jumpable, cannot deliver the necessary amperage to start the motor, but still run accessory systems.
  I would check the battery’s voltage with a multimeter.
  I doubt this is a loose terminal connection. If the click you’ve described is coming from the engine compartment, that’s the starter relay switching. Wouldn’t be able to do that if there weren’t a complete battery circuit.
  
  Take both the battery terminals off, if there are crusty white or blue gunk on them you can use a little vinegar to clean it off. Clean the contacting parts of both terminals and where they connect to the battery with a wire brush till the metal looks at least vaguely shiny. Put the terminals back on and tighten them down with a wrench, if its an american car its usually a 1/2" if its an import its almost certainly a 10mm. If it doesn't work after that try jumping it again, if it still doesn't work its probably the starter or starter solenoid. You can try tapping on the starter solenoid with a hammer to unstick it as a temporary fix to get you going, but if you have to do that then it needs replaced sooner rather than later anyways.

It's that clamp again (or the other one). Take them off, clean the terminals good, put them on again.
When starting, leave all the lights and the AC off for the first minute.
- Ok. I had made sure that the clamp was fully down on the post but I couldn't check to see if it was snug. I'm hoping it's just a matter of tightening the contacts since that's the cheapest option.

Make sure your negative actually has good contact. For a time the jumper then goes from the inside of my fender to battery was bad and my truck would randomly die and wiggling that would get it to start again until I replaced the wire end. That said yiu probably needto replace the ends.
- IIRC I had it replaced a few years ago due to corrosion.
  I'm hoping that it's just a matter of needing to tighten the contact around post since that'll just cost me some of my time.
  
  Even if you have to replace the connector, its a five dollar part and 2 bolts, if your comfortable tightening it, replacing it isn't much more. Hopefully tightening it gets it.

With power and no start (confirmed by that other car connected in parallell, presuming that you had good connection), I would think it's the starter itself, or something as simple as a fuse.
That click you hear, where does it come from? Can it be the starter relay?
Grab a voltmeter and measure for the starter - Does it get power when someone else turns the key?
Obligatory: I'm not a mechanic. But I drove a 1995 car until March this year, and I did most of the maintenance and fixes on it myself. And I troubleshoot other electromechanical contraptions for a living.
- Feel like traveling to the middle of no where woods of SC, USA?
  
  If you're paying, sure.
  NB: I don't cross the Atlantic on economy class. I'm sure your local Diesel denizen is cheaper.

Have you tightened the clamp?
Is there anything on the battery post? Do you see any build up on battery post?
How old is the battery?
- Not yet, had to wake up the wife to give me a ride into work(we work at the same place I just have an earlier shift) but once I get off I'll be doing that first.
  During the jump I let it sit for about 5 minutes and revved the wife's car twice.
  I don't think the battery is older than 5 years. But I could be wrong, as I didn't check.
  
  To clarify, when you jumped the car the negative battery cable was connected and the car would not start.
  Trace the battery cables and make sure they are both cables are properly attached at both ends.
  Batteries last 3-5 years.

There is no valid reason the clamp should be "slipping off the post" unless there is either something wrong with it, or the battery post is mangled, or both. I think you've already correctly observed the root of the issue. Start there.
Cranking the starter is the sole and single operation with the highest current (amperage) draw out of anything you can do with your car. If either of the battery terminal clamps are making shitty contact, they won't be able to pass that current and you won't be able to run the starter. The other accessories in your car may indeed work just fine if you have a poor battery contact. Your AC blower, lights, radio, etc. draw maybe 8 or 10 amps in total, with everything on full blast. Your starter motor will happily draw hundreds. All of that current needs to pass through the battery terminal clamps first.
Take the clamps off, clean the insides of them with a wire brush (assuming they're the ring shaped type), clean the battery posts of any built up crud as well, reinstall, and ensure that you can firmly screw down both clamps. If the nut on either of them is stripped or they won't tighten down for any reason, either replace the nut or replace the clamps themselves. You can get replacements at any auto parts store and they crimp onto the battery cables.
There's supposed to be a special crimping tool you use for this but no one in human history has ever bought one of those. Rather, we just mash the shit out of the crimp connection with a pair of pliers. It'll be fine. You will have to uncrimp the factory clamps by levering the crimp apart with a big screwdriver or similar. If you're lazy and have enough slack in the cables you can also just cut the old ones off and strip the wire back a little more.
It may also be possible that your battery is on the way out. They don't last forever and they do lose capacity over time. Most auto parts places have a load tester they can hook up to determine if your battery is truly toast, or if it's marginal. That will require you getting the car there first.
Start with the battery terminals.
- 10-4. I think the slipping may be because my apartment has a speed bump directly in front of it(meaning I drive over it at least twice a workday) and the SC humidity is freaking ridiculous. But as soon as I get off work I'm going to try tightening the clamp nut. Fingers crossed that is the solution.
  
  Check whatever mechanism holds the battery down while you're in there. Possibly it'll be a metal strut across it held up with some long threaded rods or a plastic wedge thingy that engages against the foot of it. If your battery is bouncing around in your engine bay unrestrained it's going to cause you problems. (Not least of which being occasionally shorting out against the underside of your hood, if it's a top post type...)

Is the starter getting juice
Tighten the battery terminals, they shouldn’t slip off at all.
Your wires could be rusted enough to cause problems. You should have a ground wire that goes from the engine block to the negative on the battery, sometimes using the body/frame to complete the circuit. If that’s rusted or is loose then you’ll have something’s working but the starter won’t.

29 comments