Snow starts

Whenever it snows, the next day my truck won’t start. I changed battery last week when it did this and she started right up. I’ve sprayed starter fluid, all liquids are topped off, still won’t start. She turns but doesn’t start and when I pull key out is when she almost starts but, shakes it off

I hear fuel pump. Battery is 4 days old with the 800 cranking. Liquids are all there. No corrosion at terminals.

If the pump is on, and the starter motor works, check for spark. Suspect coil, wires, maybe crank sensor, etc.

The relationship to snow suggests it may be problem with the high voltage circuits in the ignition system. Years ago my dad installed an aftermarket electronic ignition system in his truck, and after that whenever it rained or snowed the truck wouldn’t start. He had to install a bypass switch which reverted to conventional ignition to get it to run those days. It didn’t seem to run any better on dry days with the electronic ignition compared to the conventional, but he still switched in electronic ignition when it was dry … lol … Anyway, one idea, get a spray bottle filled w/water and mist the engine compartment while it is idling. See if the engine starts to misfire or bog down when spraying any of the high voltage wires.

Very interesting. Thank you. Seriously. First to give me a more logical
explanation.

Electricity behaves a lot differently at high voltages than the low voltages used in radios and computers. In the latter as long as there’s a little plastic insulation separating the copper wire conductors there’s no way for the electricity from one wire to short circuit into the other. But at high voltages that’s no longer the case. The electricity can short circuit right through the air if the voltage is high enough. And at lower voltages it can still short circuit through the air if there’s a lot of water vapor in the air. It’s a good thing that electricity behaves itself at low voltages, otherwise radios and computers would be much more expensive, or even impossible