I have a 1990 honda civic dx and on the way home on Sunday it died and wouldn't start again. I pulled a plug wire and I have no spark. I replaced the ignition modual, and the coil but still no spark. Would it mak any difference if I replaced the whole distributor?

Yes, the next step is to replace the distributor housing. In all liklihood, one or more of the internal sensors (CKP, TDC, or CYL) are bad. I recommend that you only buy a genuine Honda distributor housing, since we have had many new aftermarket distributors not work on this site.

Ok so I replaced the distributor with an OEM one, but I still have no spark. Ive been told that the next step would be to replace the ECU. Does that sound right? And is there any way to check to see if it is bad?

These are the steps in the Sticky that I assumed you had already performed, since you had replaced the ICM and coil:

1. Check Engine Light (CEL) Tests. If the CEL does not go out, most Civics will not spark and the fuel pump will not run. Therefore, all efforts should first be directed to correcting the problem(s) that prevent you from being able to answer "Yes" to the three basic diagnostic questions below:

a. Turning the ignition switch to ON (Position II), not START, does the CEL come on and then go off after 2 seconds? If not, the problem is with the ACG (ALT) (S) 15 amp fuse, in the under dash fuse/relay box; ECM (perform the K-Test); main relay; or the ignition switch. Perform tests in that order.

b. When the CEL goes out, do you hear and/or feel the Main Relay "click"? If not, repair or replace the Main Relay.

c. During the 2 second interval that the CEL is on, do you hear the fuel pump in the gas tank run? If not, check that the fuel pump works by jumping terminals 5 and 7 on the main relay connector and then turning the ignition switch to ON.

2. Check all under dash and under hood fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-3.html#post252145

Be very thorough, since it will save a lot of time and money.

3. ECM K-Test. Remove the MAP Sensor connector and turn the ignition switch to ON (Position II). Using a multimeter, check for 5 volts going between the MAP Sensor connector's reference wire (+) and ground. As you look at the connector, this is the socket on the right. Really press the black test lead into a cleaned main ECM ground on the thermostat housing. If the voltage is low, it's probably indicating ECM failure. Most failed ECMs will record a fraction of a volt. To me, the K-Test is simple, elegant, and accurate.

4. Check for codes.

5. Check for power to the distributor. Turn ignition OFF. Disconnect the 2-P connector from the distributor. Turn the ignition switch ON. Measure voltage between BLK/YEL (+) terminal and body ground. There should be 12+ volts read. If not, repair open in BLK/YEL wire between the 2-P connector and ignition switch.

6. Check the ignition switch for wear, pitting, or melting:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-2.html#post224652