1996 993 Stalling Problem
 

My 993 started stalling when simply driving down the street. Brumos here in Jacksonville determined that the battery ground cable had deteriorated (i.e. increased resistance), so they replaced it. This is something that I never would have anticipated. They also replaced the DME relay, which may or may not have been necessary.

I had already installed a ¼ turn battery switch on the ground cable last year, and had I known that the ground cable had gone bad, I would have replaced it with a standard coated copper cable rather than the exposed woven copper cable that is Porsche's standard part.

It's fairly common for the stock 993 woven ground cable to deteriorate internally, particularly given the corrosive environment around the battery and that the newest of those cables are now 17-18 years old.

It's just one of those things most people never think about until it starts giving trouble. Over the years, I've solved a number of "electrical problems" on my cars simply by cleaning/replacing ground cables/connectors.

A few years ago, I diagnosed an intermittent no-start condition as a main battery ground lead with high resistance. Cable looked fine, but wasn't! Later, when I replaced my battery due to a couple of weak cells, I found that the car idled better and low speed operation was smoother. I can only surmise that low battery voltage at low engine speeds was causing a weak spark condition..

After a top end reseal I forgot ground strap from starter housing to the body. The car would crank over but not start. Then attached the cable everything was fine. So I can see whete bad and corroded ground cable can cause many other problems