Truck won't start after rain

[lhommec13]

Tried starting the 100 after it sat out in the rain overnight, but it only cranks but won't fire. This is after the truck just sat out in the rain; I didn't actually drive it DURING the rain. One week before this, I drove it in the rain and parked it overnight as usual. Next morning it wouldn't start. Had to wait 24 hours before it would start up perfectly fine again. It also happened two weeks ago, but had to wait 48 hours after rain ended before it started again.

Any thoughts on what's happening? Once it does finally start, it runs perfectly normal and starts up again when I try again right away . And when it just cranks but doesn't fire, the cranking sounds normal as well. I brought it by my mechanic's shop but because it was running fine, he couldn't diagnose the problem without actually seeing the problem. And when the problem does show up again, I won't be able to drive it TO my mechanic for him to see

Searched and found a few cases where the truck wouldn't start, but none of the scenarios involved rain.

Thanks in advance...

 

[Trunk Monkey]

Tons of scenarios involving rain. Search for clogged sunroof drains and poorly installed replacement windshield leaks.

 

[lhommec13]

Tons of scenarios involving rain. Search for clogged sunroof drains and poorly installed replacement windshield leaks.

Explain how either of these scenarios leads to engine not starting? I had a leaky windshield two years ago but had it fixed. No interior leaks since.

 

[TXLX100]

Explain how either of these scenarios leads to engine not starting? I had a leaky windshield two years ago but had it fixed. No interior leaks since.

This would be the first clue. I know on some other Toyota SUVs a poorly installed windshield can lead to water entering the GEM. What does it do specifically when it doesn't start? Do dash lights come on? Any noises at all?

 

[lhommec13]

This would be the first clue. I know on some other Toyota SUVs a poorly installed windshield can lead to water entering the GEM. What does it do specifically when it doesn't start? Do dash lights come on? Any noises at all?

Nope, absolutely nothing out of the ordinary. Just cranks and cranks but does not fire. No unusual lights, noises, or anything. Thinking about just leaving the truck at my mechanic's garage before it rains again and hoping the problem arises when he tries to start it up.

 

[Trunk Monkey]

The ECU and fuses are right where water can enter the cabin and get wet from either a sunroof or windshield leak.

 

[Lc80series]

Wet spark plugs?

 

[1loudLX]

Nope, absolutely nothing out of the ordinary. Just cranks and cranks but does not fire. No unusual lights, noises, or anything. Thinking about just leaving the truck at my mechanic's garage before it rains again and hoping the problem arises when he tries to start it up.

When you put the key in the ignition, does the red security light flashing on the dash turn off?

 

[lhommec13]

When you put the key in the ignition, does the red security light flashing on the dash turn off?

Yeah it does. My initial search led me to key immobilizer and MAF issues, but I checked both on mine and they came back clean.

 

[cathaan]

I just had this happen to me after a rain. I checked and replaced fuses just in case, even re-seated the relays. Still no go.
I forgot I had a OBD II bluetooth adapter in my glove box so I plugged it in and started torque(android app).
After letting it read the codes the red light quit blinking and the truck fired right up.....
I think its a coincidence, but we shall see how it goes.
My little red light is very hard to see btw, so it was hard to know if it was blinking or not.