Truck Won't Start After Rain? WTF?

Not really sure why, but sometimes my truck has a hard time starting after it gets rained on. For example, a couple months back after a 3 hour rain storm, I tried to start her up and the engine cranked, but it just wouldn't turn over. This morning, after an all-night ice storm, same story. Quick details, bought my 04 with less than 50000 miles a couple months back, and the guy who had it before me was an older gentleman who didn't drive it very much. Maybe a spark plug or cable issue?

 

Might be a coincident.

If its having a hard time starting up that sounds like the starter might be going. Sometimes moisture can effect the contacts in the starter. Either that or the fuel pump might be going too.

 

My guess would be the temperature causing you grief rather than the rain. Possibly could be the plugs. Plugs should be replaced every 30k, so if you haven't done it yet I would consider it.

 

Would it be the starter if it cranks? Fuel pump is a good possibility!

 

I think it's the temprature. My '13 with less than 1200 miles doesn't like starting in the cold. It cranks at full speed but just doesn't want to light off. I bet it has something to do with etanol content/water saturation in our fuel.

 

Any way it could be a leaky distributor cap? A buddy thinks that might be the problem.

 

Do you have a 4cyl or V6?

V6 dont have dist. caps, they have coil packs

 

Well, that answers that question...v6.

 

I am having a similar problem, but mine is a 2nd gen. Although mine does not seem to be temperature related at all. Having gone through a rough winter, my 2013 Tacoma never failed to start or had any issues at all in cold temperatures. Yet now, mid-May, nearing summer, we are in the heavy rain season in my region. Following harsh rain storms, my Tacoma exhibits similar symptoms as described by others. It ramps up when the key is turned, but struggles to turn over. During days in dry weather, it has no issues at all, only directly following intense rain storms does it struggle in any way. It has roughly 18k miles on it currently, so it is still a ways off from any regular maintenance part replacements.

Is there anything under the hood that is exposed to moisture that shouldn't be? Mine is the 4.0, TRD Off Road with towing package. Anyone discovered the cause of this yet? If so, perhaps we can cover or add something to protect whatever it is that is exposed to moisture, and causing this problem?

 

Water sitting on top of the spark plugs shorting out the COP's? Pull one of the COP's and see if you have any water in there. If so, blow it out with a compressor or hairdryer and use some dielectric grease.

Its possible the humidity from the rain is condensing just enough to cause problems.

 

Meh?

The problem you are having is caused by a defective wiring harness and ground point location Toyota technical service bulletin (TSB) # EG042-04 states: Some 2003 -- 2004 model year Tacoma (V6) vehicles may experience an intermittent
extended or “hard” engine cranking at start up. A revised engine wire harness and ground point relocation is required to correct this condition. APPLIES TO: 2003 - 2004 model year Tacoma vehicles equipped with 5VZ-FE (V6) engines.