Quote: Directly to the frame is ALWAYS your best bet - for grounding everything. Least # of attaching points for the starter / alternator. Next best is something that is welded to the frame. Worst is something that is bolted to the frame. Doing voltage drop tests are always in order when doing / checking grounds.
Not close to correct...........in fact that is the WORST way to wire a ground system. Just because people do it all the time and it is passable, does not make it right. Work with a lot of EFI cars as I do and you will quickly find the flaws in this type system. Your frame or sheetmetal is a TERRIBLE conductor.
What I do on all the EFI and actually everything I wire now, is a "floating" ground system. I attach a copper bus bar on rubber isolators under the dash. I run the cable from battery to bus bar and run all high draw grounds to this bar, such as ignition, pumps, fans, etc. I also tie both heads together and run a ground wire to bus bar as well. The ONLY thing I ground to the actual chassis or sheetmetal is the lights
Monte
So Monte, are you saying that the only stuff that is critical to have the floating ground is the electronic stuff and not necessarily the rest of the analog stuff like starter, lights, fan, water pump, etc...? That's a whole lot easier to swallow than a complete rewire of a car to add EFI. Them wires under the dash are hard to get to on my junk, and the dash isn't coming out without cutting bars.
You are asking for a MAJOR headache with what you want to do...........and if I recall correctly, is the EXACT reason that I am not wiring your car for you. I told that I WOULD NOT do it, unless you let me rip all that stock crap out and wire the car RIGHT and you were NOT on board with that. You are asking for a MAJOR headache. Been there, done that and won't do it again. We have HAD this conversation standing in my shop. I refuse to chase gremlins on a car with a modern EFI and 40 year old factory wiring. Not worth it
Monte
Someone misunderstood my question. So I will ask again... Is it acceptable to have the electronic stuff like ign and modules operating on one power system and the analog stuff on another, thus maybe avoiding the noise spikes from water pump, fans, fuel pumps, lights, line lock, TB? They meet at the battery terminals.
I wasn't asking you to rewire my car in the message, and I have (unfortunately perhaps) moved away from the idea of EFI and will blow through instead.
You also had a lot on your mind that day.
I know you weren't asking me to wire your car. But you asked a question and I answered it. And the answer was, in my opinion, it is a MISTAKE to try and integrate modern electronics hand in hand with 40 year old wiring. You are talking about two totally separate systems. Well how you gonna do that. You have ONE car and ONE battery, so how are you going to have stock stuff on this circuit and new stuff on this circuit. It just doesn't work that way.
So in my opinion and this is strictly MY opinion........you are making two serious mistakes. The first is going blowthrough, the second is not rewiring the car.
And it doesn't matter what I had on my mind or what was going on. My thoughts on your project haven't changed. All that factory wiring serves ZERO purpose for what you intend to do and is only asking for trouble to leave it in there..........Not to mention this has been a race car for a long time and all sorts of wiring changes over the years. So STRIP it, do it RIGHT. You didn't want to.
