Car won't start when wet

JPM540 · 08-09-2012, 12:25 PM

Interesting problem. The other day I pulled my car out of my garage to wash it. After washing I wantd to pull back into the garage but car would not start. Engine cranks but does not fire. I waited about an hour, tried again and it started.

Earlier today I was out for a drive, came homejust before a significant thunderstorm. Car was outside in the rain. Same problem. Engine cranks but does not start.

Car is an 87 cabriolet. Anyone have any ideas? The top does not leak, no water on the inside,

CCM911 · 08-09-2012, 12:43 PM

I would bet the farm that you have water making its way through the engine lid vent and ending up on your distributor.

Flat Six · Flat Six's Garage

Quote:

Originally Posted by CCM911

I would bet the farm that you have water making its way through the engine lid vent and ending up on your distributor.

Yup, disty cap & wires

pete3799 · pete3799's Garage

Spray some WD-40 in the dist. cap next time it happens.

JJ 911SC · JJ 911SC's Garage

Quote:

Originally Posted by CCM911

I would bet the farm that you have water making its way through the engine lid vent and ending up on your distributor.

I put a towel on top of the engine and wiring.

You should put your keys in a ziplock bag on top of the towel...

Flat Six · Flat Six's Garage

Quote:

Originally Posted by JJ 911SC

You should put your keys in a ziplock bag on top of the towel...

Smart . . . don't want to fire up the beast and have that towel caught in the pulley or sucked into fan -- seriously bad juju.

Hunt3R · Hunt3R's Garage

Check dist cap first, but I had a similar problem recently and it ended up being that my #2 plug wire connector where it attaches to the spark plug was corroded and loosely attached. So I cleaned it out with WD40 and a wire brush and put a bunch of dielectric grease on it and reattached it and this time I could feel it really snap onto the spark plug tight. Hosed my engine down and it cranked and idled fine and I've driven it in the rain since then too without issue.

spuggy · 08-09-2012, 04:07 PM

I've power washed the motor/engine bay, drive my car in the wet without blinking and left it parked in the rain for weeks at a time (plenty of water gets in through the tea-tray grille). The only time it failed to start was when my "intermittent" yellow wire problem went solid.

They're not supposed to be "dry-only" cars; +1 on dizzy cap and plug wires being the most likely cause, although you might want to check condition of connectors on the engine harness and the 14-pin plug. You could have grown potatoes in mine...

Hugh R · 08-09-2012, 04:42 PM

Quote:

Originally Posted by JJ 911SC

I put a towel on top of the engine and wiring.

You should put your keys in a ziplock bag on top of the towel...

Smart, I put a piece of tape on the ignition switch.

stlrj · 10:47 PM

The 911 distributor cap was never designed to be waterproof. Usually not a problem since most do not drive their 911s in the rain.

EMJ · 08-10-2012, 07:12 AM

Apply Permatex dielectric grease to all plug wire boot and dis cap connection points.
Remove each plug wire from the spark plug, add grease to the inside of each connecting boot, re-attach. Do the same with plug wire at the dis cap connections.

Also apply it to the dis cap mating points - simply create a seal with the grease where the top of the dis cap joins the bottom part. I had your issue for months and this fixed it. Never had any problems since.