words and images by frank nicosia

old one, the original, at the top compared to the new one at the bottom.
I've read a few internet postings that claimed big improvements after the owners replaced their ground straps; so naturally, I became curious.

Although my 20+ year old ground strap appeared to be in good condition, I decided to replace it just to see if I noticed a discernible difference in the performance of my 1991 Porsche 928 S4...I was really eager to see the results for myself. 
It seemed like a relatively cheap item to replace to begin with, and being that it that could potentially offer significant returns, I really had nothing to lose—so off I went.

Now the old ground strap seemed fairly new and free of corrosion. The visible surfaces gave no indication of any problem lurking beneath the protective rubber covering. As you can see in the photo above, the old ground strap on the top, appears deceptively similar in condition to the new ground strap on the bottom. 
look at that thing...and it looked so nice on the outside!
After removing the ground strap, I gave a quick cleaning to both battery terminals and the ground point where the strap meets the body, and I also the ground point with 220 grit sandpaper and a squirt of Deoxit spray. 

A dissection was in order. I brought the old ground strap to my work bench and cut open the plastic sheath just to see how the inside looked. The end connected to battery had a surprising amount of corrosion concealed below the rubber covering, but the other end that was connected to the body appeared brand new inside. 


I figured the gasses emanating from the battery must take quite a toll of these things. 
the most awesome Deoxit Cleaner, I swear by this stuff. (image: www.ipatools.com)
before the swap...needle is just above 12 volts.
Prior to removing the old ground strap, I snapped a quick photo of the dash voltmeter. Although the dash voltmeter generally is not 100% accurate, I used it to establish a benchmark and gauge any improvement. 

As you can see from the photo on the bottom, there was a noticeable increase in voltage, even the dash lights seemed brighter. The TPMS light in the photo looks considerably brighter in the “after” photo (I run non-stock 18” wheels, that's why it's illuminated). 
the voltmeter is right where it should be, notice the brighter TPMS?
The pleasant surprise was that the car now seems to idle smoother since the ground strap installation...that made me very happy.

Since many 928s are considerably older than mine, the level of corrosion could be substantially worse. Why not invest 10 minutes of work and a few bucks; the dividends could be huge!
Frank Nicosia has been with flüssig since the very beginning. He's the proud owner of the black on black '91 928 S4 you see below that looks like it just rolled out of the factory floor...he's also one hell of a nice guy and tons of fun to be around to boot. Stay tuned for more of his experiences he's looking forward to sharing with us. 


07/01/2014 16:44

I had a similar problem in an old car i had, but the reason was a shut-off switch on the ground line of the battery. Many years i tried a lot of repairs all over the car (ignition, battery, spark plugs...) untill i discovered the real reason, and the bad thing is that this was noticed days before i sold the car =/


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