brucec59

I posted in the "Wont start after washing" thread that my car ran rough after hosing down the engine bay, a problem a few others had (after washing enine or after heavy rain). Well, it happened again after the car sat out in last Friday's heavy rain. It had a little trouble starting, then ran very rough - clearly not firing on all cylinders. After 10-15 minutes of driving, it was back to normal. I've been thru two pervious winters with this car, including parking outdoors during rain, and I never had this problem.

It was suggested in that other thread that the culpit could be the spark plug wires, and to check by starting the car in the dark and looking for a light show in the engine bay. I did that last night, and saw nothing.

But I still suspect plug wires. Mine are about 104k miles old, after all. But what else could it be? Coils? Distributors?

Thanks.

Dudley

Hi Bruce,

You may be looking in the wrong area for the light show. When I changed my plug wires, the top side was fine. The bottom wires, that you need to pull the rear wheels to see, were cracked and weathered.

I wonder if disconnecting the coils, one at a time, might point you in the direction of your trouble.

marret

Sure appears to be water related, could be plug wires, coil, distributor. Seems like once the water "burns off" the car runs fine. I had this kind of problem on my 911SC and a new set of plug wires cured it; the plug wires were much more exposed. Actually had the same problem on a motorcycle and new wires cured it too. If you haven't, you may want to make sure all coil wire boots and all spark plug wire boots on the distributors have a good seal, have no cracks, etc., and make sure the distributor caps are not cracked. Inspect the coils for cracks. If the above look fine, probably time to replace plug wires based on miles and symptoms.

Marlon

Maybe you won't see a 'light show' unless the humidity is higher or the leak is really bad, etc. A spritz bottle with tap water works great. Or you could have a loose boot that is allowing moisture to enter the wire terminal on the top of the plug, or a loose coil connection. Now sure how 'wet' you can get the lower plug wires during a routine car wash unless you deliberately spray water under the engine??? My 115K mile 95' 993 had lower plug wires that were cracked to hell and back but the car NEVER misfired and ran like a deamon. Just a thought.

95 C4 993

For what its worth, my wires were in rough shape at 60k. Ignition coil needed replaced and had the distributor rebuilt ---one distributor cap was cracked.

23 hours of labor and $3400 in parts later on my 60k tune, much better!!

brucec59

OUCH!

Thanks, guys. I'll check things out more closely. Maybe a boot has come loose.