My '92 Civic recently developed a problem. It will randomly not start. When this happens, I will turn the key and see the CHECK LIGHT come on and no noise from engine area (fuel pump?) and the CHECK LIGHT stays on. It will crank but never start. I usually wait for 10 or more minutes then try it again. When it does start it happens this way: I turn the key and the CHECK LIGHT comes on, I hear a hummm from the engine area and then the CHECK LIGHT goes off. At this point I have no trouble starting the car. What is going on here and what do I need to do to troubleshoot this? I am guessing a relay or the fuel pump but I don't know where to start. Email is [email protected]

thanks,

-william

Sounds like your ECM is failing. When this happens, it prevents the main relay from working. Perform the K-Test to confirm this:

The 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.

O'Reilly Auto Parts sells remanufactured ECMs, with a lifetime warranty, for around $275--Honda wants over $1,000 for only a 1-year warranty. Ensure the replacement is an exact part number match.

Here's how to replace it yourself:

https://www.askmehelpdesk.com/cars-t...tml#post235038

As it turns out the problem in this case was the MAIN RELAY. It is located under the driver's side dash and is well know for having cracked solder joints. I took it out and resoldered the cracked joints and problem is solved. Note, this problem never happened on wintry days.