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BavMoWo
10-25-2011, 09:10 AM
Got an electrical problem (worst week for it too... 3 exams and a paper due... Always happens, doesn't it?). Recently, I had the battery disconnected because of replacing some gauge cluster lights. I hooked everything up and even drove for 3 days. Hooked the battery up again last Wednesday and drove the car every day since then. On Saturday, I drove the car to a place, parked it on a flat area, and shut the car off. Decided I should move the car, but when I got in and turned the key, the electronics shut off. Tried it a couple times (switching key all the way off then back on), walked back to the trunk to check the battery, and as I was removing the box that covers the battery (it's the stock one, so that's not the problem) the electronics popped back on (I had the key turned and heard the antenna start to raise up). Got in the car, started it right up. Drove the car every day without trouble until now.

Today (the next Tuesday), I had the car parked on a slant in my driveway (haven't been parking there normally, but had to when I got home last night). When I walked out to start the car this morning, same issue. Walked back to the back to look at the battery again, SAME THING happened. Tried to start the car, but this time the power cut back off as soon as I tried to turn the key all the way (power did not shut off until the starter would have cranked). Got a second person to try to start the car while I moved the battery. Found out that all I needed to do was jiggle the battery slightly and the electronics would come back, but that the starter would kill it again. Also, I smelled that slight electrical-spark smell in the trunk, but there was no smoke or anything along those lines. Just a light smell when you got close to it right after trying to start the car. The car never started, and the only way to get the car back on level ground is to roll it into the road...

The battery cables do not look old. There's no corrosion on the posts and the posts are tight. Both cables seem solidly connected to the posts (they're tight, no wobble or twisting).

What do you guys think? It's a 1989 325i, had it about 2 months now and had never had this problem until Saturday. I could use help on this ASAP so I can try to fix it this weekend. I don't really have reliable transport until then (gotta rely on a loan from someone, and I hate that).

T77911S
10-25-2011, 09:46 AM
it sounds like you are not getting the lugs tight on the posts.
get a battery terminal cleaner from advance and clean BOTH terminals. then clean the ground connection to the body. make sure the clamps are tight on the battery posts.

what type of battery clamps/lugs do you have? the kind where the cable is molded into the lug or the cheap crappy ones that have the 2 botls on top that clamp the cable to the lug.

richardodn
10-25-2011, 09:48 AM
Double check where the ground cable attaches to the chassis back in the battery box. When you clamped the cables back on the battery, did you clean the posts? Another possibility is the fusible link in the thinner black wire connected to the (+) battery post. When it happens again, go to the junction block on the firewall under the hood. If the thick wire junction has 12V and the thinner one is dead, then look at the link. If all these check out as good, then your ignition switch is suspect. However since you smell ozone (electrical spark smell), I think it's probably the ground cable-chassis attachment.

If it does turn out to be this, completely detach the cable. Clean the mating surfaces thoroughly. You may have to take a file to it to clean the deposits left from arcing. Use blue thread lock on the nut to keep it from coming loose. Tightening it should be very snug.

BavMoWo
10-26-2011, 06:35 PM
Well I feel like an idiot now... Apparently I didn't jiggle the wires enough the other day, because when I went to pull off the negative cable to clean and check the things you guys mentioned I found that the bolt was completely loose and the cable pulled free relatively easily. Guess I shouldn't have checked it in such a rush :P (the issue came up when I was trying to leave for class, and I was already running behind) I took the cables off and cleaned everything thoroughly since they needed it anyway, so hopefully this'll take care of it.

Thanks for getting back to me so fast, guys! I appreciate the help, even if it was my own stupidity :P