OCD is kicking in... battery in hatch?

Some disadvantage to the solenoid in the rear I foresee would be if you were trying use a jumper switch to test something under hood or bump for top dead center. As others have said it will also mean running wiring from ignition all the way to the hatch. If the solenoid sticks you have to go to hatch to kill power anyway but, now you will have another wire running from the rear to the front of your car with welding capabilities. Voltage drop between solenoid and starter could be an issue especially in a no start situation where you will try cranking starter for any length of time.

If you do the battery in trunk also do the shutoff switch. Some tracks require you do that but, relocation kits don't include them.

Depending on which starter you have ( or intend to use) the solenoid could be there. ( on the starter) It is that way w/ mine and has been w/ every other aftermarket high torque starter (for a windsor) I have used in the past 10 years. so in effect, again you only need a 2 ga wire from the battery. I also have a shut off switch back there. If you have a starter that uses the stock solenoid, then you will have to run A large primary wire and the starter circuit relay wire back as well. However, if you do have a new starter that has an integral solenoid,You only need to spend an additional 19.00 for a bulkhead fitting to bring that 2 ga wire through whatever panel you choose to bring it to, to give you another attaching point for the existing primary wiring that is currently going to your existing solenoid location.



The relay runs my fan, the red 8 ga is from the alt., the big 2 ga goes to the starter. The rest of the wires that originally went to the solenoid are on the back side , along w/ the cable coming from the battery.

whats the point of having a battery with a vent tube??

foxbodymike87 said:

whats the point of having a battery with a vent tube??

Click to expand...

If the battery is sealed in a box (like you need to do for NHRA approval) it needs a vent tube to let out the vapors that escape....

I have a hatch with battery in the trunk. I used Summits relocation kit that came with a black plastic box. I mounted in behind the passenger's seat, over the axle. Vent tube runs out the passenger side of the box and through a factory hole in the floor, which also runs straight through the frame. I am going back to do a cut off switch eventually, can't run NMRA without it, but local track doesn't even check.

I have my battery in the trunk and I hate it!! I also hid the starter solenoid and wires which wasnt a big deal at all. But I've had nothing but problems with my battery in the trunk and I did everything the right way. Sure looks clean though

You probably have seen this before, but just in case you haven't, here it is....

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 1/2" 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 1/2" 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 a turn on signal 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.

The fuse & wiring in the following diagram are for a 3G alternator. The stock alternator uses a dark green fuse link wire that connects to 2 black/orange wires. Always leave them connected to the starter solenoid even if you have a 3G alternator.



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.




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
Note: The quick disconnect may have fallen victim to damage or removal by
a previous owner. However, it is still of utmost importance that the black/green
wires have a high quality ground..

Picture courtesy timewarped1972

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.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring
http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

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

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

The grounding diagram provided above is crucial. That is the ONLY proper way to ensure adequate grounding for a rear-mounted battery. Installing a single ground from the battery to the trunk body is not enough. A #1/0 ground directly to the engine block and then the body again is very important. A unibody frame is a terrible means of completing an electrical circuit. People tend to overlook grounding, and then they wonder why their EFI cars are having so many issues. Anytime I troubleshoot electrical issues, I check grounds first.