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Unusual problem starting car

I have a 1990 honda civic dx. with only 115,000 miles. For the most part it runs great, but for the past year it has given me problems when I try to start it. What happens is that at random times, it just cranks, but it doesn’t start. Sometimes, if I try it several times (as much as 20 attempts) it will eventually start. Sometimes I have to leave the car for some time (10 minutes up to a few hours) and then it will start. I checked the spark, when it doesn’t start, and it has a good spark.This seems to happen mostly when it is hot, never at night. But since I live in Florida, this is a problem most of the year. My mechanic changed the distributor and that did not solve the problem. The ECM gave 16 flashes. My mechanic is frustrated in dealing with this because often it starts right up. Please help!

If it still had spark i do not understand replacing the distributor. I would check for power to the fuel pump. It could be something as simple as the fuel pump relay.

Does this problem occur when you try to start the car first thing in the morning? Or, does it happen when you try to restart it after it is warmed up?

Heat can cause fuel to vaporize in fuel lines. High pressure (as in all fuel injected cars) in the fuel lines cuts down on “vapor lock” but sometimes it can still happen. Your fuel pump could be weak and not generating enough pressure. There is a pressure regulator that could be bad. If your Civic does not have fuel injection (then it has a carb) vapor lock is more likely due to low pressure in the fuel lines.

Not too impressed with your mechanic, this shouldn’t be too hard to track down.

The problem might be with the PGM-FI main fuel pump relay. Honda’s have a history of not starting in hot weather because this relay developes cracks at the solder joints. The relay is located behind the dash, above the drivers left knee.


As Tester states, this is a well-known problem with Honda cars from the 90s. It can be fixed by replacing the main fuel relay.

Or you can try to save some money and make your own repair. This video shows you how:

i would not be too harsh on the mechanic. i had a 1994 honda civic in my shop for over a month and used every resource available, even an electrical genious, and still the engine cranks but does not start. having said that when she finally does start she runs great. someone mentioned pgm-fi relay, it is the root, but the ecu is not getting the signal to ground

In my experience if the car won’t start and you can find the relay under the dash, then you can give it a good thwack with a hammer while cranking the car and the car will start. I got pretty good at this back in the day, and the car would start almost instantly. Probably not a good long term solution because hitting things is a good way to break them, but it’s a way to confirm the relay is the problem.