6 Month sitting car will turn over but won't start

[Sevorith]

So I'm having an issue with my e30 now that wasn't a problem before. After moving here to Texas the car has kind of sat waiting for some funds to continue working on it. The last time it was physically driven was a few miles from my apartment to my new house in December, where it has since sat. Before that it had sat since about October while I tried to drive it at least once a week to work.

A couple of weeks ago, I started it up and let it run for a few minutes in the garage. Yesterday I went out to find that the battery was completely dead. I jumpstarted it with my DD to find that it would crank but not start.

My first guess is that the fuel might have gummed up the lines. Since I got here to Texas I only put 93 octane in it, dunno if that's better or worse. I think, sitting right now, it has about 1/2 to 3/4 of a tank left, maybe more.

So what should I try? Add in fresh gas? Maybe an additive? Try starter fluid and see if it'll stay running?

[Sevorith]

Forgot to mention that it's an 88 318is with an m50b25tu swap.

[turbo55]

Doubt the fuel could have gummed up in that short of a time. If your battery is dead, maybe you have a short somewhere that is draining the battery and not lettering you start?
Also, check for fuel, check for spark. At a minimum, you can jump the fuel relay to listen to see if the fuel pump is turning on or not.

[Sevorith]

It could be a short. I've had issues with the battery dying before. I had it diagnosed and the shop said there wasn't a parasitic draw and the the battery was bad. They replaced it with a brand new one. The confusing part is that it sat for a while before and when I went out and started it a few weeks later it started right up. I can't figure out why it would decide to die between then and now. When I turn the key I hear a whirring sound that I assume is the pump. A friend of mine thinks that maybe the battery I was using to jump start it didn't have enough juice to keep it on while trying to start it, as the battery would just drain to nothing while trying to turn it over. I have a voltmeter in the car that showed the battery charging up to 13.5. I would try to turn it over and after a few seconds it would slug out and the voltmeter would drop to around 5 volts. My next plan is to get a charger and charge the battery overnight, then see if that helps.

[Sevorith]

Just a quick update. Charging it worked, so it doesn't seem like any other issue than electrical. I'm going to take it out this weekend when it's nicer and when I don't have any time constraints to make sure it starts up okay and drives right. It seems like I still have electrical issues that I need to take care of. I think my next step is to do my own parasitic draw test since it isn't apparent if the shop did it or not.