87 toyota tercel won't start in wet weather

My 1987 Toyota Tercel wagon works very well – except that it won’t start in wet weather. Maybe this is condensation somewhere, maybe not. Please help me out on this.

I owned a Tercel of that vintage as well. What I discovered was that using aftermarket ignition parts (cap, rotor, plug wires and spark plugs) made this vehicle VERY susceptible to starting problems in wet conditions. When I installed all OEM ignition parts (from the dealer) all of my wet weather starting conditions disappeared.

By not “start”, I assume it cranks ok, but doesn’t catch and run. And I’m assuming the routine engine maintenance is up to date consistent with the owner’s manual. If not, that’s the first thing to do. Since you mention wet weather, the secondary electrical system would be the first suspect. A visual inspection of the plug wires is what I’d probably do first. Twist and bend the insulation on the plug and distributor wires and see if you notice any cracks in the insulation. The ignition coil would be next. Remove it, place it on the work bench with good lighting, and if necessary use a magnifing glass, and see if you see any tiny cracks forming in the housing.

You may have to start just replacing stuff to get this fixed. Before I did that though, I’d probably take a garden hose with a sprayer, start the engine, and spray various sections of it with water and see if the engine stops when a certain area is sprayed, to isolate the problem.

More than likely moisture accumulating inside the distributor cap. If so, wipe it dry and spray the cap and wires down with WD-40.