Battery relocation

Rear mounted battery ground wiring. Follow this plan and you will have zero ground problems.

One 1 gauge or 1/0 gauge wire from battery negative post to a clean shiny spot on the chassis near the battery. Use a 5/16” bolt and bolt it down to make the rear ground. Use a 1 gauge or 1/0 gauge wire from the rear ground bolt to a clean shiny spot on the block.

One 4 gauge wire from the block where you connected the battery ground wire to the chassis ground where the battery was mounted up front. Use a 5/16” bolt and bolt down the 4 gauge engine to chassis ground, make sure that it the metal around the bolt is clean & shiny. This is the alternator power ground.

Crimp or even better, solder the lugs on the all the wire. The local auto stereo shop will have them if the auto parts store doesn't. Use some heat shrink tubing to cover the lugs and make things look nice.

The computer has a dedicated power ground wire with a cylindrical quick connect (about 2 ½”long by 1” diameter. It comes out of the wiring harness near the ignition coil & starter solenoid (or relay). Be sure to bolt it to the chassis ground in the same place as you bolted the alternator power ground. This is an absolute don’t overlook it item for EFI cars

He speaks the truth. haha

To be NHRA legal (so you can race at a track) you will need a sealed box usually (sometimes they will let you get away with no sealed box in a coupe) a on/off switch clearly on the outside of the vehicle that will shut off the car when swithed off, and a vent tube.

JBeezy53 said:

Do you need a box at the track if you use an optima battery?

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I've never had a problem. Places differ though.

Good luck with installing the on/off switch. I'm still yet to figure out how to get the car to actually turn off when the switch is switched to the off position. It will kill the power to everything electrical but it wont kill the engine. I ran the seperate wire from the alternator back to the switch with a circuit breaker. That works for about 5 minutes until it overheats the circuit breaker and trips it. I heard you can put a diode in one of the alternator wires but I have yet to figure that out.

To kill the engine the switch has to be in between the ignition switch and the engine. You have to kill the spark or the power to your ignition. Think of it this way, will a car start with the coil wire off? My buddy had his wired wrong to where he could flip the switch and it would stay running and he was denied any track time that day.

Yeah? So I need an ignition wire going back to the kill switch along with the positive battery cables?

I believe it also has to kill all electrical power to the car not just kill the engine.

Here is what I suggest....

got pics? I want to do the same under the floor in the spare tire hole. If you guys can help me too. Couldn't find in anything in the search part.

JBeezy53 said:

What does this wire look like? Colors?

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The computer
has its own dedicated power ground that comes off the ground pigtail on the
battery ground wire. Due to it's proximity to the battery, it may become corroded
by acid fumes from the battery. It is a black cylinder about 2 1/2" long by 1"
diameter with a black/lt green wire. You'll find it up next to the starter solenoid
where the wire goes into the wiring harness.

GearHd6 said:

Good luck with installing the on/off switch. I'm still yet to figure
out how to get the car to actually turn off when the switch is switched to the off
position. It will kill the power to everything electrical but it wont kill the engine. I
ran the seperate wire from the alternator back to the switch with a circuit
breaker. That works for about 5 minutes until it overheats the circuit breaker and
trips it. I heard you can put a diode in one of the alternator wires but I have yet
to figure that out.

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For a battery cut off switch, see http://www.moroso.com/catalog/categorydisplay.asp?catcode=42225
is the switch http://www.moroso.com/catalog/images/74102_inst.pdf is the installation instructions.
Use the super duty switch and the following tech note to wire it and you will
be good to go.

Use the Moroso plan for the alternator wiring and you risk a fire. The 10
gauge wire they recommend is even less adequate that the stock Mustang
wiring.

There is a solution, but it will require about 40' of 18 gauge green wire.

Wire the battery to the two 1/4" posts as shown in the diagram.

The alternator requires a different approach. On the small alternator plug
there is a green wire. It is the sense lead that turns the regulator on when
the ignition switch is in the run position. Cut the green wire and solder the 40'
of green wire between the two pieces. Use some heat shrink to cover the
splices. See http://fordfuelinjection.com/?p=7 for some excellent
help on soldering & using heat shrink tubing.

Run the green wire back to the Moroso switch and cut off the excess wire.
Try to run the green wire inside the car and protect it from getting cut or
chaffed. Crimp a 18 gauge ring terminal (red is 18 gauge color code for the crimp
on terminals) on each wire. Bolt one ring terminal to each of the 3/16" studs.
Do not add the jumper between the 1/4" stud and the 3/16" stud as shown it the
Moroso diagram.

How it works:
The green wire is the ignition on sense feed to the regulator. It supplies power
to the regulator when the ignition switch is in the run position. Turn the
Moroso switch to off, and the sense voltage goes away, the voltage
regulator shuts off and the alternator quits making power.

See the following website for some help from Tmoss (diagram designer) &
Stang&2Birds (website host) for help on 88-90 wiring and lots more…

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

Diagram courtesy of Tmoss and Stang&2birds.

Wow! Jrichker... Thats some awesome info. Thanks a lot, I appreciate the help. I've been trying to figure this out for some time now.

See http://www.skycraftsurplus.com/ for the cable at a very reasonable price. Welding cable works good, it is flexible and comes in the right sizes.

JBeezy53 said:

Where's a good place to get the cables? I've looked all over the internet and they are expensive! I'll probably buy them from summit.

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I just use my local welding supply store. Make sure whatever you do you get welding cable. You can thank me later when you realize how easy it is to work with.

I just got teary-eyed... saw my old s/n with the BANNED under it

so sad