Wet Weather Car Trouble

January 8, 2005 1:58 PM

ClickandClackFilter: My car will not start in wet weather. [+]

Soon as it dries up, she fires up like a dream. Battery is fine. The terminal connections look ok. Any ideas?

posted by spicynuts to travel & transportation (24 answers total)

What happens when you try to start it? Does it try to turn over? Just click? Nothing at all?
posted by mendel at 2:01 PM on January 8, 2005

What happens when you turn over the ignition? It could be a bad starter motor or alternator, or wiring shorting out from water.
posted by AlexReynolds at 2:04 PM on January 8, 2005

What model is it? And could you give us the year? That would really help my brother a lot, not that he doesn't enjoy working on mystery cars.
posted by Smart Dalek at 2:09 PM on January 8, 2005

When our VW Golf was doing this (not turning over at all in wet weather) we had bad ingnition wires going to the starter. It might help if you try starting the car in the dark with someone looking under the hood (assuming it's wet out). If it isn't wet, you can have the person checking use a spray mister on the starter and look for sparks. When we did this to our car, sparks came out and the car died, giving us the answer.
posted by spaghetti at 2:21 PM on January 8, 2005

Distributor cap, spark plug wires, coil wire, ignition wires.

Any one of these can short in wet weather.
posted by mr_crash_davis at 2:40 PM on January 8, 2005

Ok..all your questions answered:

1992 Honda Civic (2 door, little bugger..can't remember if it's DX or LX)

When I turn the key, the starter cranks like it's trying to start but it just never catches. That's how I know it's not the battery. It tries to turnover. When it's dry, it starts immediately.

Assuming it's wiring, am I looking at an expensive fix?
posted by spicynuts at 3:05 PM on January 8, 2005

What mr_crash-davis just said. Replace the spark plug wires first, followed by the distributor cap. It's probably one of these two and the wires are cheaper.
posted by Mayor Curley at 3:07 PM on January 8, 2005

Most likely spark plug wires. Work up from there. Its happened on two of my cars.
posted by skallas at 3:46 PM on January 8, 2005

Is this something I can do myself? Or, since it's messing with the electrical system, should I have a pro do it to be safe?
posted by spicynuts at 3:48 PM on January 8, 2005

You are, quite simply, not getting spark.

For your purposes, the spark starts at the ignition rotor, goes through the distributor cap, into the plug wires, and eventually to the plugs.

Before you replace anything, put a good, light coating of dielectric grease on all contacts. That means the ignition rotor, every pickup inside the distributor cap, every connector outside of the distributor cap, both ends of your plug wires, and the (outside part of) the plugs themselves. Depending on the design of your wire boots, you may find that a Q-Tip makes application easier.

Remove and replace the wires one at a time. Do not leave more than one wire disconnected at once.

If you still need to replace wires, do not buy cheap wires. The "Gates" brand often stocked by discount auto parts stores is of inferior quality to the wires you can get from your dealer or NAPA (Echlin brand).
posted by trharlan at 4:10 PM on January 8, 2005

trharlan: beg to differ, but the spark starts at the coil, and THEN to the rotor. I've had the same problem and the culprit was the coil. mr_crash_davis has the answer.
posted by Daddio at 4:18 PM on January 8, 2005

Make that NAPA Belden Brand, not Echlin.

Honda says to replace the cap and rotor every 60,000 miles, so it wouldn't be a bad to replace them anyway, if you have the spare cash and the time. Quality wires will set you back $50, and IMO you shouldn't replace them unless you know them to be bad.

You can do all of this yourself. If you are nervous, just disconnect the battery negative terminal before you work on the car.

On preview, Daddio, I used "for your purposes" because coils and coil wires go bad so rarely (maybe 5% of the time it's the coil and coil wire rather than a downstream ignition part, IME). And if you're going to be a pedant, you could say that the spark starts at the battery or the alternator, depending on whether the car is running.
posted by trharlan at 4:25 PM on January 8, 2005

eh, unless you really know what you're doing, take it to a shop. The 92-95 civic motor was complex enough that it could be a number of things - ignition system, plugs, coil, ecu, fuel pump, mass-airflow sensor, injectors / injector harness, etc... You're more likely to waste your time and money replacing parts that are not broken w/o the proper tools to diagnose what's going on. Good luck.
posted by jba at 4:43 PM on January 8, 2005

Even though it's complicated, jba, what percent of intermittent damp-start failures are related to the ecu, MAF, fuel pump or injectors? Of course, it's possible, but it's not bloody likely.

Anyway, (pimping my own advice) the grease will set you back $10-$20 and is likely to fix your problems.
posted by trharlan at 4:55 PM on January 8, 2005

You guys are great for mechanical questions.

We had a car that did this when I was a kid. My mother couldn't afford to take it to a garage. She didn't have the AskMe mechanics to turn to either. So, she figured that something under the hood was damp. She blowdried (with a hair dryer) the engine until she narrowed it down to the distributor cap. Every time it rained and she had to drive somewhere, she'd grab her blowdryer before leaving the house. And to think she never took a mechanics class.
posted by Juicylicious at 5:05 PM on January 8, 2005

Awesome. Thanks, everyone. I'll do this out on the street in Brooklyn. Maybe I can impress some ladies walking by with my grease monkey skillz. Boo ya.
posted by spicynuts at 5:06 PM on January 8, 2005

You can do it. It is less complicated than an oil change.
posted by Doohickie at 5:32 PM on January 8, 2005

well trharlan, my thoughts are essentially "what electrical componants could have problems in the wet that would keep the car from starting?". Someone with a honda diag tool will be able to tell you in 2 minutes, whereas spicynuts might spend days pulling parts trying to find the problem. Oh well, working on cars is fun anyway. :-)
posted by jba at 5:45 PM on January 8, 2005

On some dry night (when you can start it) you might look under the hood while the engine is running, you might see sparks jumping from the offending component. WD-40 and the like used to advertise themselves as ignition system dryers, but I'm sure that its now a bad idea (I'd do it in a second to mine, but my car is 50 years old), probably pollutes the mass air flow sensor or some other electronic gewgaw. 4x4 people sometimes spray an ignition system sealer on their wire, cap and coil to prevent the engine from stalling in deep water, you can get a rattle can at auto parts stores.
posted by 445supermag at 6:11 PM on January 8, 2005

IAMNAM but my 91 Camry had this exact same problem which turned about to be the ignition coil. I replaced the coil (sucker that I am) but apparently it's not difficult to remove and clean.
posted by Asef Jil at 8:08 PM on January 8, 2005

Clean a coil? Usually, if an engine is misfiring or not starting because of a coil, it is because it is shorting out on something; not sure how a cleaning would help that.

I'm not familiar with the model in the original post, but The Things That Go Bad In An Ignition System are (in order of ease of replacement) are:

1. Spark Plug Wires
2. Distributor Cap (& the Rotor Inside It)
3. Coil

There are some additional distributor components beneath the cap & rotor, but you usually don't have to mess with that stuff.
posted by Doohickie at 9:55 PM on January 8, 2005

Oh... forgot to mention: The coil is easily found by following the ignition wire that comes out of the middle of the distributor cap.
posted by Doohickie at 9:56 PM on January 8, 2005

I'm truly out of my element here, but apparently the ignition coil may become coated with carbon dust.
posted by Asef Jil at 10:18 PM on January 8, 2005

I had a problem with an old Audi where it had trouble starting in wet weather. But it got much worse when my car was low on gas. I finally figured out that water was getting into the fuel line and watering down the gas. Fill the thing up with fresh gas and it would turn over immediately... Don't know if that helps. Good luck.
posted by Heminator at 9:46 PM on January 9, 2005