Could One bad ground cause the batterie not to charge correctly?

Wont fire up off of one batterie. BUt when i Throw 2 Batteries in it and have the other one grounded in the rear end It fires right up. and Every thing is normal. But the minute i take the wire off of the second batterie it Dies...

I looked at the main ground for the batterie and it was like completely Melted. and i Swapped The old ground for a brand new one and still wont fire up without two batteries and suggjestions or something?

 

Any one know any thing lol?

 

Maybe bad battery cables? Or bad alternator not charging it?

 

Already thought alternator. put a brand new one in :P

replaced cables to

 

When you swapped the ground what guage cable did you go with? And did you just reground to that same place, or did you find a new place to ground to?

 

Start with this. Don't skip any steps or take any shortcuts.

Renix Ground Refreshing
The Renix era XJs and MJs were built with an under-engineered grounding system for the engine/transmission electronics. One problem in particular involves the multiple ground connection at the engine dipstick tube stud. A poor ground here can cause a multitude of driveabililty issues, wasted time, and wasted money replacing unnecessary components.
The components grounding at the dipstick tube stud are:
Distributor Sync Sensor, TCU main ground, TCU "Shift Point Logic", Ignition control Module, Injectors, ECU main ground which other engine sensors ground through, Oxygen sensor, Knock Sensor, Cruise Control, and Transmission Sync signal. All extremely important stuff.
The factory was aware of the issues with this ground point and addressed it by suggesting the following:
Remove the nut holding the wire terminals to the stud. Verify that the stud is indeed tightened securely into the block. Scrape any and all paint from the stud’s mounting surface where the wires will attach. Must be clean, shiny and free of any oil, grease, or paint.
Inspect the wire terminals. Check to see that none of the terminals are crimped over wire insulation instead of bare wire. Be sure the crimps are tight. It wouldn’t hurt to re-crimp them just as a matter of course. Sand and polish the wire terminals until clean and shiny on both sides. Reinstall all the wires to the stud and tighten the nut down securely.
While you’re in that general area, locate the battery negative cable which is fastened to the engine block just forward of the dipstick stud. Remove the bolt, scrape the block to bare metal, clean and polish the cable terminal, and reattach securely.
Another area where the grounding system on Renix era Jeeps was lacking is the engine to chassis ground. There is a braided cable from the back of the cylinder head that also attaches to the driver’s side of the firewall. This cable is undersized for it’s intended use and subject to corrosion and poor connections at each end.
First off, remove the cable end from the firewall using a 15mm wrench or socket. Scrape the paint off down to bare metal and clean the wire terminal. Reattach securely.
Remove the other end of the cable from the rear of the head using a 3’4" socket. Clean all the oil, paint and crud from the stud. Clean the wire terminal of the cable and reattach securely.
A suggestion regarding the braided cable:
I prefer to add a #4 Gauge cable from the firewall to a bolt on the rear of the intake manifold, either to a heat shield bolt or fuel rail bolt. A cable about 18" long with a 3/8" lug on each end works great and you can get one at any parts store already made up. Napa has them as part number 781116.
A further improvement to the grounding system can be made using a #4 cable, about 10" long with 3/8" terminals at each end. Attach one end of this cable to the negative battery bolt and the other end under the closest 10mm headed bolt on the radiator support just forward of the battery. Napa part number 781115.
　
　
If you want to upgrade your grounds and battery cables in general, contact Jon at www.kelleyswip.com. He makes an incredible cable upgrade for a very reasonable price.
　
Revised 11-28-2011

 

Alternator.
Once your jeep is on you should be able to remove the battery and have it still run, if it dies then your alternator is dying/dead.

Edit: nevermind

 

My alternator is 2 days old now lol

 

Does any one else know what would cause my alternator not to charge my batterie?

THE ALTERNATOR IS BRAND NEW BTW

 

You must have voltage from the battery via the cable between the alternaotor and battery, and with the key on, you need to have voltage from one of the two wires in the plug. I can't remember which one.

 

Oooh excitor!

 

Not a good Idea on any computer controlled vehicle.

 

That's the word I was looking for at 3:45 am!!!

 

Thank you, never knew that was lacking on the renix, I just wondered why they bundled the grounds like that.

 

That stuff drove us nuts when we were at the dealership in those days. Thankfully I made friends with some really helpful guys at JeepTech and they pointed us in the right direction. Just trying to pass on what they gave us. It works.