Thread: car wont start after battery relocation

bought a bnew oddessey pc545 and mounted it in my trunk with stinger 0Gauge cable and grounded it to the spare tire nut thing in the hatch. It works somewhat like it would turno the engine over but it would struggle and my batt reads 12V, but today when i went out to move it to shovel it turned over real slow and wouldnt start. Im thinking its the batt. cable being so long sucking the juice before it gets to the main harness, but im not 100% sure. Im just wondering if i should buy some racing batt. cable from pegasus because the stinger 0G is just not good for this application, or should i just move the batt. back into the engine bay with some SAE terminals? what would give me the best battery performance?

You need a better ground for some 0 gauge...I would create your own ground about 2 feet in length from the battery at a spot on the floor of the trunk...make sure it's properly sanded and drill the hole yourself. Let me know if this doesn't fix your problem.

yeah that ground is awful that you have

I agree, you want th eground wire to be as short as possible and to a thick ancor point. That spare tire nut has a crap connection to the chassis.

Brent

ok thanks for the help. I sanded the anchor and re tapped it thinking that was what everybody used, but i guess not. BTW-i put the battery in the jack bracket after i modded it to fit so the ground is only about 2 ft long and i used gold plated terminals. Can i measure the resistance of the ground to determine if it's good? Is there a certain resistance that the ground should be under? Like the MAF?

hey morgan i want you to come down...and help me do my relocate

I grounded mine to the rear strut tower bolts in my trunk. The problem I am having is where I connected the wires in the engine bay. Sometimes it will act fine until I go to actually start the car, and when I turn the key it will just click shut off like the battery is dead. If I get out and litterally just touch the wires where they have been extended in the bay it will come back on. If I don't have those wires in the perfect location it will just do that repeatedly until I find a good spot and then it will turn over fine. Sometimes if it's close - but not perfect - it will turn over real slow like that. So also try checking your connection in the engine bay.

you want to really use the biggest wire you can, with the biggest bolt you can, going as direct to the chassis as you can. And yeah, the shorter the ground wire the better. Just find some place that goes directly to the chassis, preferably an existing m14 or m16 bolt or something, sand off the contact surfaces completely, and bolt that sucker down.

OK. I see theres a goldish colored bolt with a big washer on it with a 14mm head(don't know what size that is in metric) about a foot from the spare tire nut on the hatch floor just outside the spare tire well that i think i should try. Just for fun i went out and measured my ground and its reading .2ohms. At first the reading would jump around from .1-.6 depending on where i placed the test leads, but then it stabilized at .2 on the bolt heads that secure both sides of the cable. I assume thats going to give the best reading on the bolt heads that secure it.
Is .2ohms bad?? Should i disconnect the positive lead on the batt before i measure the ground also?

I'm trying to imagine that bolt, but it sounds like it's worth a try. And, 14mm is metric

Personally I'd be shaky on 0.2 Ω. I'd look for something in the 1/100th's range. 0.02 Ω would be much better.

As for the testing spot, i'd test it at another location on the chassis. Remember, it's got to travel all the way up the car to the engine bay, and just because the bolt head thats fastening it has a good ground doesn't mean that ground is making it's way uninhibited to the chassis. Test at a variety of locations that should get the ground signal between the negative battery post. Don't extend your leads, though, only test spots that are within range of the meter's leads.