I was leaving a friends house tonight, started up my car fine, then about 5 seconds later it shuts off. I try to start it again and it wont start at all. It'll just keep cranking. My "low battery" light also was on, but when I cranked the car it didnt sound like the battery was low.

Here's a little overview of my car...
I have a B18A in my 91 CRX SI. I completed the swap about 2 months ago, its been running very rich since(i get about 20mpg). I also have code 6(TPS Sensor), code 7(Engine Coolant Sensor), and code 13(atmosphere sensor). Some things I've noticed in the past couple days is that my main relay will continously click sometimes after I shut my car off, and my ECU will display the CEL codes when the key isnt in(is it supposed to do that?).

Someone please help! Thanks.

 

ttt...