86 300zx not starting

[jdkirkham1]

I have a 1986 300 ZX non-turbo that will not start. I have had it since July 2017. It has been running fine until 2 weekends ago. Upon starting it was running really rough with black smoke coming out of the exhaust. I am assumed it was running rich. After I turned it off it would not start. I waited several hours tried again and it started, still running rough. On the ride home it suddenly started running normal. Drove it last week, went to work Friday and it hasn't started since. I ran diagnosis on ECU. It gave me codes 12, 13, 21, and 41. I replaced the Air Flow Sensor last night. It first tried to start, then nothing. It is now showing 23, 31, and 41. It has plenty of fuel. You can smell it. It has spark at the distributor. Thanks for your input.

[PapaSmurf2k3]

Yeah it sounds like you're running super rich. I'm not sure what those codes are other than misfire, but you should be able to look them up either via google or in the factory service manual. www.nicoclub.com/fsm
I know a coolant temp sensor can cause all the things you're talking about too. Might be a quick and easy thing to check out.

[evildky]

Code 41 is the fuel temp sensor and it like the chts will cause a rich condition. usually just the connection is bad. That code 21 could be the distributor taking a dump.

[PapaSmurf2k3]

Mine used to act funky and wonky before I replaced my wiring harness. I actually put an adjustable fuel pressure regulator on there so I could adjust if needed just to get me home. I'd have to dial the fuel pressure way down to like 8psi