Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - What would cause a car to not start when it's humid ?

Cd · 12-01-2011, 09:34 PM

OK guys, I have a puzzling problem with my '93 Civic DX :
Like clockwork, my car will fail to get electricity to the fuel pump when there is even the slightest bit of humidity out.
If there is even a single dark cloud on the horizon, the car will fail to start.

If i turn the key to the ACC position ( the second click of the key before the third click that starts the car ) the fuel pump does not come on. When i remove the main relay and trip it, the fuel pump comes on fine.

The main relay is a brand new unit.

I have replaced the fuel pump with a brand new pump

The distributor might seem to be the problem, since the car has very weak spark, but this doesn't explain the way the fuel pump acts by not coming on when i turn the key.

I am replacing the distributor this weekend regardless.

The only other thing i can think of would be a short in the ignition switch wiring. I posted about this problem on a honda forum about a week ago, but only got one response, so im posting here too just for the hell of it.

I was told that the ignition switch could be tested by checking the main dash lights that come one as you start the car.
They all check out fine, so i'm puzzled.

12-01-2011, 09:34 PM	#1 (permalink)
Cd Ultimate Fail Join Date: Feb 2008 Location: Austin,Texas Posts: 3,585 Thanks: 2,872 Thanked 1,121 Times in 679 Posts	What would cause a car to not start when it's humid ? OK guys, I have a puzzling problem with my '93 Civic DX : Like clockwork, my car will fail to get electricity to the fuel pump when there is even the slightest bit of humidity out. If there is even a single dark cloud on the horizon, the car will fail to start. If i turn the key to the ACC position ( the second click of the key before the third click that starts the car ) the fuel pump does not come on. When i remove the main relay and trip it, the fuel pump comes on fine. The main relay is a brand new unit. I have replaced the fuel pump with a brand new pump The distributor might seem to be the problem, since the car has very weak spark, but this doesn't explain the way the fuel pump acts by not coming on when i turn the key. I am replacing the distributor this weekend regardless. The only other thing i can think of would be a short in the ignition switch wiring. I posted about this problem on a honda forum about a week ago, but only got one response, so im posting here too just for the hell of it. I was told that the ignition switch could be tested by checking the main dash lights that come one as you start the car. They all check out fine, so i'm puzzled.