Here is what I know...

90 honda civic dx 3dr 1.5L manual. Was receiving a code 4, replaced entire distributor, rotor and cap. Started great the first time, after the engine warmed up it backfired and stopped running. Now, when you turn the key, the CEL comes on and goes off as normal but it won't start. You can smell fuel in the exhaust and there apears to be spark. It looks like the coil and ignitor are part of the distributor? Any ideas would be appreciated.

The Crankshaft Position Sensor (CKP) failed. Did you install a genuine Honda distributor? We have had many new aftermarket distributors fail on this site. CKPs are not serviceable--try to get your money back and buy a Honda distributor.

Here's a recent example:

https://www.askmehelpdesk.com/cars-trucks/1994-honda-civic-dx-wont-start-289152.html#post1413520

It was purchased from NAPA if that matters? I ran out of time last night to check a few more things and am going to do a little more troubleshooting tonight. I'll look into the site you linked as I'm trying to get out of the office for my 2.5 hour drive home.

I finally got a chance to change the distributor. I purchased a genuine honda distributor from my local dealership. It is still coming up with an error code 4 but it starts and runs now. I can drive it even after it warms up. It occasionally acts like it's miss firing when it's sitting idle at operating tempature. If I wait it will either go away after a couple seconds or the check engine light comes on and the car runs differently. I can't acelerate passed a certain rpm (no tachometer in car) or it bogs down. I've tried timing it and I thought it was around 18 degrees but I'm not sure as the marks are very hard to see. Is it possible that the TDC censor in the new distributor is bad? I've checked the wiring and the tdc censor in the old distributor was deffinately bad (shorted across not perticular ohms it should have been). Any ideas anyone? I also replaced plugs, wires, cap, rotor, and engine ground wire. Figured it couldn't hurt to replace those. The injectors have been replaced already about 6 months ago.

Sorry to double post but I suppose I should also note that the previous issue above was caused by the rotor coming off. The screw holding it on came loose. I used the previous screw which needed an allen wrench to put in. it seems to be fine aside from the issue that I have now. I was about to pull the cap off the distributor to check but it was already very late at night and I was falling asleep standing.

I've never seen a hex-head cap screw used to hold the rotor, even though it could be fine if the metric threads were correct. Normally, #2 Philips head screws are used.

After fixing the rotor, does it run well?

A #2 screw is what was used and no matter how much I tightened it, it would come loose. (which is what caused the problem posted above.) now it runs great except when idling at a stop light it acts like it missfired and will eventually (after running for an hour or so) act like I had pulled one of the plug wires off followed by the check CEL turning on. Once the CEL turns on, the car runs great but you can't rev it past about 2500-3000 rpm and it backfires. I was guessing it was the timing which I thought I had set correctly but the marks on the pulley are gone and I did my best to find and remark it. Does this help?