I have a 91 crx with a obd0 b16 swap and ls cable trans. This past Friday I started my car just fine got about 4 miles when it died suddenly in the middle of the road. I thought it might be my battery. So I went and got my battery and alternator tested. Turns out I had a bad diode in the alt. And the battery was low only 300 amp not 500. So I did the logical thing and got a new battery and alt. I replaced it and the car turned over just fine it ran for about 10-15 min after that I got in and tried to drive and it died. I tried to start it again and it didnt turn over. It would sound like it wanted too but didnt. I would have to try and turn it over numerous times and it would start but but then die shortly after. So I can eliminate the battery and alt. Right now but im stuck on what it could be. From what I searched it could be anything from a main relay ignition switch a bad fuse flywheel issue or numerous other issues. My issue here is that these were for problems similar to mine but not quite it. So im asking for some help before I give up and take it to a garage. Any help or input would be great.

 

replacing the battery and alt without proper testing doesn't eliminate their components from being the issue, which it still could be.

sounds like theres an issue with the alternator, and your car ran for a while on the new battery.

other then that does your fuel pump prime? check no start thread in faq.

 

Are you sure the battery and alternator are installed correctly? Make sure the battery connectors are properly tightened to the battery when you try and start it, and that the alternator is properly connected too the cable and the harness. I know it sounds silly, but I just thought I would mention it since that might easily be overlooked. If that is all good then I would recommend looking at these possibilities:
Test the main relay. https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/checking-main-relay-pics-2535047/ This is a common problem, and was in fact a problem on both of my EF cars. The main relay is usually a very simple fix. If you can solder, you can fix it. The way to fix it is to re-soldier the bad connections on the circuit board. Most of the time the soldier connections get old and crack, and thus the repair works. Less often, you have to replace the main relay. Have fun bolting that thing back in there haha. its kinda tight under there.
Another cause could be a problem with the ignition system. Simple things like plugs, wires, rotor, cap, coil, ICM could be the culprit. I don't think you have a major problem on your hands; its probably a simple fix and I think I got you pointed in the right direction.
Oh yea, and make sure your ground wires are good… that can cause all sorts of weird problems. This is probably not your issue anyway, but it could be.