Washed my 82 Eruo yesterday like I've done before. Upon startup it seemed to be running on 5 cylinders. My first thought was water got in somewhere. Checked the distributor, dry. Pulled each plug wire one at a time to see if I could find the dead cylinder. All were firing. Hmmm.
Opened the gas cap to realase pressure thinking vapor lock. No dice.

Ended up taking it down the road and taking it up to redline in 1st. Around 5k RPM she opened up and started running fine. Been fine since.

Any idea what could have gotten wet that would casue a definite rough running and power loss (just like a cyclinder that isn't firing)?

The only other thing I can think of that it felt like was a partial blockage in the fuel system?

Ideas?

 

I know exactly that happened. Gremlins - "Little, mischievous spirits of tools and machinery. Originally they were friendly towards mankind, and helped them with many inventions. But when those engineers and mechanics claimed all the credit of these inventions for themselves, this insult soured the gremlin attitude towards mankind."

 

AKA if it is working move on .. don't anoy the Porsche gods...

 

Mine does the same thing after it rains, if she gets caught out in it. I check the cap (new), wires, plug wells, etc. Runs rough for a few, warms up, all is forgiven.

 

Well unfortunately it did it again today and I didn't wash it, it's been in the garage all night, and the Italian tune-up didn't work this time. Seems like she's running on 5 cycls, but when I pull wires the idle drops down. Almost felt like it was running on 4 today. Sounded exactly like an old Beetle.

Any other ideas as to what could cause this? Car has been running great except for an overly rich mixture at cold startup that causes wandering idle that I haven't been able to get to yet.

 

How long since spark plug wires were replaced?

Test: Wait till dark, start car and let it warm up, use a spray bottle of water(not hose) and heavily mist all the plug wires. If wires are older and breaking down, you will see visible arcing to ground.

Just one suggestion.

 

Mine would not want to start when wet before I reploced the Cylinder Head Temp sensor. ( 2-3 hours, lots of cursing depending on your garage setup). Never established cause and effect but it was suggested by former Porsche shop owner.

Also had a bad Injector wire which would cut in and out. Giving the Running on 5 cylinder effect. Could be effected by moisture.

 

On an '82 SC I would lean toward the injectors as the culprit. Pull the spark plugs, I'm sure that you will find one that's darker than the others. Replace the injector on that cylinder, and go for a drive! If your injectors feel loose, be sure to buy a new injector sleeve, a sleeve o-ring, and a new injector o-ring.

 

Well it would seem that I have a bad plug wire on #6. Pulled all plugs. #6 was slightly black compared to the nice grey tan of the others so I conentrated on that cylinder. Swapped #6 and #4 plugs to make sure. Warmed it up today so that the idle was nice and stable. Pulled the offending wire and no change in idle and no snap/spark from the wire when shorted to the block. Not sure how I missed that yesterday.
Guess I'll order a new set of wires.

Thanks for the help guys!