I have just signed up to this forum and i hope u guys can help me out. I own a 91 mustang gt. I just recently moved the battery to the trunk in order to free up some space under the hood for future modding. I grounded the negative wire to the rear of the frame and ran the positive wire threw the interior, threw the firewall and to the stock mounting location. The engine fired with no problem but after driving it for a day the car began to barely start or not start at all. This would happen after about 3-4 hours of use. i dont kno whats causing it and i would appreciate it if you guys could give me some suggestions about whats going wrong. the car is stock except for a pro 5.0 shifter, k&n in box filter, and the battery relocation kit.
Starting Problems 91 GT
- Thread starter l2ol33rt
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stangbear427
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Agreed. You may also want to run a heavier alternator feed to the battery, you may want to check your alt to see what the output actually is, and check it at the battery not the alt. What size wire did you use for the 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
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
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