I have 1995 honda civic dx that won't crank until the check engine light goes out ,I have replced the main relay, it no good,, any ideas?, thks for any help

The ECM is likely bad--perform the K-Test on it:

The K-Test: Remove the MAP Sensor connector and turn the ignition switch to ON (Position II). Using a mult-meter, 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.

Here's how to replace the ECM yourself and save yourself a bundle of money:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-3.html#post235038

If the K-Test indicates the ECM is bad, look into buying a remanufactured Cardone ECM from O'Reilly Auto Parts, with a lifetime warranty. It will likely cost around $275, while a new ECM from Honda will cost over $1,000 and only come with a 1-year warranty.