I have a 90 Civic with the 1.5 with 276 thousand miles and am having a problem. I looked at several similar descriptions here and seen some helpful responses but not enough to solve mine.
Engine starting running real rough and barely made it home. I fueled it the day before so I assumed it was fuel related. Would not start.
Replaced the fuel filter and noticed a vacuum line from intake to MAP sensor freshly cracked and added a splice to repair.
Pulled spark plugs and noticed they were black and very sooty. Installed new ones.
Seems to be good spark at the plugs, but still no start... Must be fuel related.
I am about to check fuel pump via main relay, and as far as I can tell the fuel pump is located in the tank? Sweet.
So, am I missing anything obvious? The blacked sooty plugs have me somewhat baffled. I do not think I have ever heard the two second fuel pump start with this car, and maybe since its in the tank that may shield the sound? Bah.

Miss my little Civic.. sniff

Bob in Colorado.

As taken from a spark plug analysis write up "Basically, soft, sooty carbon deposits, as shown below, have a dry, black appearance. If only one or two plugs in a set are fouled, it is a good practice to check for sticking valves, a cracked distributor cap, or bad secondary ignition wires. Fouling of the entire set might result from an incorrect heat range spark plug or an over-rich air/fuel mixture caused by a clogged air cleaner filter element, a sticking heat riser valve, or a faulty choke. Fuel injectors that malfunction can also lead to this condition.

Other causes include weak ignition system voltage or an inoperative pre-heating system (carburetor intake air) or poor cylinder compression."


So first check the air filter and the ignition wires and pull the dist cap off and check the rotor and inner part of the cap


And then do a comp test

Spark Plug Analysis

Reading sections A and B below should help:

https://www.askmehelpdesk.com/cars-t...das-46563.html

If everything appears to check out, after reading sections A and B, focus on the distributor; i.e. igniter, coil, and sensors. AutoZone will check igniters and coils for free. Even if the spark is good, it may not be firing at the right time, due to a faulty igniter or bad sensors. After that, check the MAP Sensor.

Thanks to all who helped, and txgreasemonkey for taking the time writing that great primer for those who need help.
In my situation the MAP sensor vacuum line broke causing the engine to run really rough and leaving the sooty deposits.
Once I repaired the MAP sensor and reset the ECU, no errors came up and it started right up as normal.