1992 318i Starting issues

[Lie]

I have a 1992 318i that is having issues starting. It is able to start just fine with a freshly charged battery etc. However, it is not charging the battery as it should.

Recently, I was able to start it up and travel roughly a half hrs drive and then I stopped for lunch and when I came back to the car to start it, it cranked a couple times then died. After a friendly stranger's help in jumping the car, I was able to take it another 2 hrs to my final destination with no problems at all (had headlights running, radio, etc)

The next day I was able to start it up just fine and ran some small errands around town.

Later that night I was not able to start it up again. I got the battery and alternator checked out at a local shop, they said the battery tested fine and the alternator showed zero output. However, this does not make sense to me because if the alternator truly had zero output then the vehicle would have stalled on that two hr drive and not been able to continue especially with all of those things running (radio, headlamps, etc)

Since then I have been able to jump the car and drive it on several short drives without turning the ignition off. (One 1.5 Hr drive, One 1 Hr drive) But after every time it must be jumped.

Any idea what the issue could be? I've been advised that it's most likely a short circuit or something somewhere. I'm open to all suggestions on how to isolate this problem and fix it. :help

tldr; Car not starting due to not enough power, yet alternator supposidly works and battery checked out fine, car is able to start when jump started and will not stall out

[flyfishvt]

You have an issue with the charging system. It may be working once in a while but if all the connections are good and clean then it sounds like you need a new alternator. Used ones are pretty cheap. Just an FYI....even if your alternator is working if you drain the battery and don't drive the car long enough to charge it back up you will continue to have issues starting it and you'll need to jump start it until the battery gets a good charge.

The fact that your battery wasn't fully charged after a 2 hour drive says you have a bad/loose/dirty connection at one of the battery terminals or the alternator or the alternator isn't working properly

As a last resort if everything checks out you'll need to start looking for a parasitic drain.

[Lie]

Shouldn't a bad or loose connection prevent the battery from being charged at all?
If the alternator was outright failing wouldnt the car stall out once the battery is drained? Especially on a 2 hour drive with lights, radio, fan etc running? Then after the two hour drive I was able to run the car the very next day with no problems

[flyfishvt]

You could easily have a loose connection at the battery or alternator that allows it to charge the battery once in a while. Alternators generally fail completely but not always.

I would clean and tighten the battery terminals and see if that fixes it. If it doesn't then move on to the conncections at the alternator (disconnect the battery first) If that doesn't fix it you are probably looking at a new alternator.

Don't be affraid to take it somewhere else for a second opinion on the alternator and battery tests.

[Lie]

Thanks I'll check all the battery terminals once this rain clears up! Any other possibilities? I'm kind of just compiling a list so that once I get the chance I'll do one big diagnostic in case it isn't this issue.

[Hellmet]

+1 on what all these guys said. Check the battery again though. I had a brand new battery once that was a dud, wouldnt charge properly at times, seemed like an alternator fault and caused hell with the car, they checked it and coz it had a bit of charge they said it was fine. Checked in another place a couple of days later adn they said it was screwed. Replaced battery and perfect.

I say this because here batteries come with a 5 year warrenty, if thats your problem you get it sorted for free.

Penis