I have a 94 Civic DX that doesn't start when it's raining or wet. I took it to a mechanic who replaced the cap and rotor, that didn't fix the problem. I took it back and he replaced the cap and rotor again, still the same issue.

I normally start the car by turning the key and listening for the sound of the gas, then finish turning the key and the car starts. On wet days, I turn the key and listen, but no sound. I can crank it but it won't start.

Sometimes when it won't start, I can press the brake pedal several times quickly and that seems to initiate the sound of the gas and the car starts. If it's really raining hard, that doesn't usually work.

My mechanic is stumped. My brother will do a repair for me, but he doesn't know what to do, either. So, I've turned to this forum . Thank you in advance for any ideas.

 

Resolder your main relay. When you turn the key but don't crank, the fuel pump should prime and the "check engine" light should go on then go out after 2 seconds. If the CEL stays on steady and the pump doesn't run like you have, it's usually the main relay.

The connection to rain that you perceive could just be coincidence. It's usually more temperature related. The relay is under the dash, so kicking things around with the brake pedal may be jostling it enough to make it work.

 

Thanks so much for your reply. You seem to understand the problem exactly the way it is. I will try to solder the main relay, and report back.

 

I've had the main relay replaced, and the car is still having the same problem .

 

After you're sure the relay is good (did they really replace the main relay, or some other relay?) the other thing that causes this problem is the ECU itself.

 

What exactly do you mean by the sound of gas? Isn't this a fuel injection engine? One would think if you hear this sound and it starts that it is related to fuel. Rain or wetness actually means there is less O2 in the air so the car needs less fuel or more air. Is the air filter clean?