First of all, sorry for the long post, but this issue took a bit of explaining. Those that take the time to read this and give me some ideas, thank you!!
So I bought this 93 Accord coupe 5-speed last week, and it ran perfect for the first 50 miles or so. The tachometer in the car only ever read at idle with the car running, and the needle would actually move down a little as the RPMs increased. Right after I bought it, I replaced the ignitor and checked that the ground on the thermostat housing was attached and there was no change in the tach behavior. I was driving on the freeway yesterday when all of a sudden the tach jumped up and started working, and the dash lights brightened, then a few seconds later the tachometer and the speedometer both dropped to 0, then jumped back up to reading again then dropped back to 0 and the car shut off. Now there seems to be no power at all, no headlights or anything. Also, after the first time the tach started working and before it died it seemed like it was running on 3 cylinders. I was able to roll off the freeway and into a parking lot, but couldn't restart the car. I thought it was probably some kind of wire short in the engine harness, so I pulled the entire harness yesterday and didn't see anything melted or any damage. I pulled the loom off of all the distributor wiring thinking that was where the short would be, because of how the tach had behaved prior to the engine dying, and the fact that it seemed like it was misfiring (weak spark?) But all the wiring was good. Also had the alternator bench tested because someone suggested that, and it tested good. Ran out of light yesterday. Had to leave the car last night in the parking lot 15 miles away from home. Was able to set the alarm with the harness out so the alarm at least is getting power.. also no fuses were blown. I'll be going this morning to finish putting the harness back on but I'm not sure what to look at next. Please, any ideas, help or direction would be greatly appreciated!

 

Can you describe what happens when you turn the key to start the car? Terminology is important here. When I start my car, I turn the key to start. The starter will crank the engine. When the engine runs on its own is when I release the key. So is your starter cranking the engine? Or will the engine not run on its own?

A faulty alarm system can cause numerous problems if it is failing. Does your alarm have a reset?

 

When I get up there to the car, and have the opportunity to try to start it, I will reply with exactly what is going on. I'll also see if I can find out if I can reset the alarm. It is a Compustar CM 6300 I believe. It is still functioning properly though, so I'd be surprised if that was the source of the problem. Is there some way to test the ECU? With a multimeter? I thought I'd pull the cover off the ECU to inspect the board and see if anything is obviously bad with it, at the very least. Unfortunately, I do not have access to another running Accord to swap ECUs to easily test it.