[DML] Re: lRe Grounding Schematic.

["content22207" <brobertson@xxxxxxxxxxxx>]

This is my ground bus itself:
http://a5.sphotos.ak.fbcdn.net/hphotos-ak-snc7/390248_279324822112775_100001057778755_853328_905437381_n.jpg

Every single OEM ground junction has been tied into it (even the two behind the headlights), including the elusive junction behind the central HVAC duct.

Speaking of which, if I am to be remembered for anything, it should not be the carburetion of a handful of cars, but rather widescale reporting of that junction. Until I unwrapped #2508's harness, I had no idea that junction was even back there. For years and years I had heard from many sources that the instrument cluster was grounded via the radio bracket. That is 100% false. I never heard nor saw anything to the contrary. For those who still need convincing, here it is:
http://sphotos.xx.fbcdn.net/hphotos-ash4/309893_282221628489761_100001057778755_861272_225725998_n.jpg
*THAT* is where the instrument cluster is grounded (and the fuel pump, among other things). It is an unfortunate design because it places too much demand on a single ground wire. Non other than Rob Grady himself told me that is what melts Fuse #7 (remember: DC electrons flow from negative to positive -- Ben Franklin got it backwards). If your grounds are inadequate, it's the positive side that heats up.

The radio bracket grounds the radio only -- that's it. The other three wires are noise reduction capacitors only. The radio bracket is a very minor player in the car's grounding scheme. You could lose it altogether, and the only thing you'd lose is your tunes.

My instrument cluster now is tied into 4 gauge battery cable:
http://sphotos.xx.fbcdn.net/hphotos-ash4/386449_294229657288958_100001057778755_894477_417856207_n.jpg
My fuel pump is grounded elsewhere -- down draft carburetors can't work upside down, so I have no need of an inertia switch (another ground weakness, which is why it often melts its harness connector).

BTW: The oft repeated mantra to "clean your grounds" does not apply to these ground junctions. They are soldered together -- there's nothing to clean. Their problem was designed in when the harness was first wrapped -- wires back to the bulkhead bolt are simply too few and too small in gauge.

Of course the ground strap at the motor mount is stupid beyond measure. Who in their right mind puts such a critical connection right next to the pavement? Remember: if you lose that strap, you lose the entire car, not just the engine compartment. Degredation in that strap degrades the entire car. Running another cable to another point on the bottom of the engine does not cure its original flaw. My battery connection is inside the weather protected interior of the car:
http://a5.sphotos.ak.fbcdn.net/hphotos-ak-ash4/390111_294243023954288_100001057778755_894562_1304124496_n.jpg
It also is immune to any fluids that could ever drip from my engine or transmission. A much better design, IMHO.

Bill Robertson
#5939


--- In dmcnews@xxxxxxxxxxxxxxx, "Cars" <twodelo2@...> wrote:
>
> 
> Bill
> 
> I like the grounding schematic you did,   It will prove useful in trouble
> shooting the most common of the electrical problems that I've encountered
> with the car.  The idea of a single heavy line through the whole front of
> the car is also logical.  I began the process several years ago but just
> went from the bulkhead bolt to the radio bracket bolt.  Your drawing makes
> it clearer where to extend its path.  But looking carefully,  a compound
> question arises (first part serious and second an attempt at humor).  I
> noticed that you did not indicate the grounding path to the horns.  (I know
> that it is through the chassis.)  Did you overlook them intentionally or is
> one of your mods to eliminate them?
> 
> I am seriously thinking of running a heavy power sub feed to under the hood
> which would allow me to install a horn relay and louder horns as a safety
> feature and at the same time reduce the load on the horn switch..  It would
> also make available 12V under the hood  for other functions.
> 
> I have had and still own several Volvos for daily transportation, and the
> electrical section of their service manual is the best I've seen.  Each of
> the break down schematics, which are similar in concept to the ones in the
> Delorean manual, indicate which connectors and pin numbers the signals pass
> through.  This allows for much easier trouble shooting.  "I can see either
> end of the signal path, but how does it get there?  Is there an intermediate
> point at which to look for continuity?, etc."
> 
> You can answer me off of the page at my address below
> 
> Al Roberts
> twodelo2@...
> VIN 16049
>




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