Have a 92 Honda civic. Would not start, fuel pump check,relay check and fuses OK. Does the ecm control fuel pump relay? Started checking voltage on MAP sensor when I plugged it back in, it started . If MAP sensor is going out will it fail to activate the fuel relay? Can the ECM be failing intermittentlyfailing to turn on fuel relay.

Sounds like classic intermittent ECM failure. Perform the K-Test at various times on the ECM and I bet you'll find it's bad. Yes, the ECM controls the main relay. MAP Sensors are extremely reliable and expensive.

The K-Test: Remove the MAP Sensor connector and turn the ignition switch to ON (not start). 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.

Here's how to replace the ECM yourself:

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

The MAP plug voltage is 5.1 volts now and the pin on the far left is 4.56 volts . The car starts and runs great now,but I do not know what was wrong earlier. I do know that the check engine light would not turn off even after the key was in the on position for 30 sec. but now it goes out. Hate to by ECM without confirmation that it is bad.But I hate for my daughter to get stranded somewhere. Where is the best place to buy one

Ideally, you want to perform the K-Test, when the Check Engine Light is on. At that time, the test may indicate the ECM is bad. That would confirm that the ECM is intermittently failing. Honda wants around $1,000 for a new ECM, with a 1 year warranty, while O'Reilly Auto Parts sells a remanufactured one, with a lifetime warranty, for around $300. I recommend replacing ECMs every 120,000 miles or 10 years, whichever comes first. Remove the old ECM first, in order to get an exact part no. match.

Thanks. This car has 267,000 miles on it. Rebuilt motor at about 190,000. I think the ECM may be original.

Stephencooper,
What was the final resolution to your problem because I have the Same SYMPTOMS with my 92 Civic LX. It only has 35,000 ORIGINAL miles on it (got lucky when I found this one, family friend owned it from new).