Disease please, I'll take two.

[ec164]

Marc your car is looking excellent, can't wait to see it completed! I like your wiring and connections, had to chuckle on your battery story  Sorry to hear of your back pain, don't sound fun...Al

[turbohunter]

Thanks Al, this getting old thing ain't for pussies.
Started getting the inside of the console together today, which means laying out the wiring.
I think I'll put a common ground off the battery on the left so I can keep all those ground wires contained.
I bent up and welded in the shelf for the relays and fuse box this morning. The computer itself is bolted to the spreader which sets the height of the console.

[turbohunter]

Because I was overwhelmed by the amount of wires you have to deal with, I thought I might document how I go through and connect and route everything in order to help those that might venture this way and if I screw up maybe it will be caught.
Yesterday I laid everything out and made preliminary connections of easy stuff. Just following the basic scheme Jay laid out in his thread. Unswitched battery 12 volt will come into the six leg fuse box. The first two connects are to the 30 pole on the fuel pump relay and the ECU relay. I ganged the 7 basic ground wires together onto one lug and will connect them to a battery grounded lug. I was going to get an insulated lug but all the stores are closed today. So I found a perfect bolt and nut in the garage and figured if I weld the bolt to the console frame I'll have a nicely grounded piece (because I'll run a large battery ground to the lug) to make other installs (like lights) easy. Of course when done routing I'll make a harness out of the whole mess.

[jayb]

Marc, the wiring looks good so far and most of those wires won't be used, so don't let the quantity of wires worry you.  However, I'd suggest keeping the grounds from the EFI electronics separate from other grounds if possible.  So, I wouldn't connect lighting grounds to that same ground point as the 7 black wires, and I wouldn't connect any of the ECU grounds directly to the frame.  You should have a single clean power and ground wire coming from the battery to run the EFI box, and use a separate power and ground wire from the battery to run the other electrical devices like lights, electric fans or water pump, etc.  Even though from a DC perspective this is exactly the same thing, from a signal noise perspective it is not.  Electrical noise is the enemy here.  Also, I would suggest a big bypass capacitor up near the EFI box.  MSD makes some for their ignition boxes that work quite well for that application.  So, I'd suggest from your ECU relay, run a big wire to a bypass capacitor.  Then run a separate big wire (#10) from the battery negative up to the capacitor.  From there, make all the power and ground connections for the EFI system at the terminals of the bypass capacitor.  This includes sensor power and ground connections, for the crank and cam sensor for example.  Don't connect any other power, or any other grounds, to that capacitor.  That will ensure the cleanest power supply for the ECU.

[turbohunter]

I was half kidding about the amount of wires. Although it is pretty daunting at first. But I've spent a lot of time separating and figuring out what I will and won't use. I think I have a good idea about it all.
I was hoping you would comment on the lights idea. I tend to get myself screwed up with the basic electric principals.
I was figuring since I was thinking of welding that battery ground bolt to the console shell, that in turn all of the shell would be grounded. So in turn if I wanted to ground into the console shell somewhere I would just drill a hole and attach a ground anywhere on the console. But I guess what your saying is that that ground loop may cause problems. So I'm guessing my original thought of an insulated dedicated ground is the better idea. Ok cool.
As far as the capacitor, is this the one you suggest? And install it off the 86 (ground) pole on the ECM relay?

https://www.summitracing.com/search?SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=MSD%20capacitor

[jayb]

That's the one.  Hook the 12V wire from the relay to the + terminal of the capacitor.  Run a separate wire direct from the battery negative terminal to the - terminal of the capacitor.  Then, just pretend the capacitor is the battery, and run any ECU 12V wires to the positive side of the capacitor, and any ECU ground wires to the negative side of the capacitor.  The capacitor basically bridges between the 12V and ground wires, and provides reserve electrical charge to damp out variations caused by electrical noise.  You want it as close as possible to the electronics, because every electrical wire is an antenna, and antennas will pick up electrical noise.  So, if you put the capacitor back at the battery, then the two wires running up to the ECU could pick up noise and inject that noise into the ECU electronics.  One of the things you learn when working with electronic circuits is to put a bypass capacitor very close to any integrated circuit.  That is basically what you are doing by configuring the setup this way.

[turbohunter]

Ok thanks, ordered.

[turbohunter]

Ok the MSD capacitor showed up so I wired it in before work today.
So here is how it's set up, hope you can follow this in the picture.
Battery power comes in to the fuse box via the front post. The computer has its own battery power circuit which is the smaller 2 amp fuse. That runs to the capacitor then to the relay which powers the computer.
The ground is set up off of an insulated clean battery ground which runs to the capacitor then to the ground post on the computer relay.
So the battery power and ground are both routed through the capacitor.

[jayb]

Looks great, Marc!  That will give you clean power...

[Leny Mason]

Hi, I hope you are making me a diagram to follow on mine, Wow how nice and thanks to Jay for the input. Leny Mason

[turbohunter]

That's why I'm going into this painfully slow detail Leny.
Hopefully between Jays thread with all the good info and my thread where a ham fisted amateur gets it going, the process will become crystal clear.
If you go with the MS3 Pro system, their instructions and diagrams are quite good.

Edited the mistake of MP3.
I'm old.

[Leny Mason]

Who makes the mp3  is it fuel or Ignition thanks Leny Mason

[turbohunter]

Here you go Leny.
You should be able to find all kinds of stuff here.
https://www.diyautotune.com/shop/mspro-efi-ems/

The company is DIY Autotune
Sorry I just realized I put MP3 instead of MS3Pro.
I'll change it.

[turbohunter]

Wow a working system. The brakes officially will stop this thing. Only thing left is all the rest

[turbohunter]

Kind of a marker. Finished everything underneath the car until engine is in. Touched up the alignment and went over every bolt. It's amazing how many you forget to tighten.
Anyway she's on her feet with steering and brakes working well.
One more thing I've learned. From now on I'm doing everything on my engines. I haven't had the room (as you can see it's tight) but as long as I've been waiting and getting the mustang done will free up space. And to tell you the truth I hate waiting for other people's @%#&.
Anyway here she is ready for an engine and trans. I've been promised  the engine soon.